Create curved meshes without using Paths? I've been looking at tutorials on how to create a curved object and all they all use paths. I'm trying to create a curved building. How can I create a tangible 3D curved mesh that doesn't involve stacking slightly rotated objects onto one another, Like a path would do?

Sorry, this may not be pleasing to hear, but there are two ways to do this.

The hard way (manually model the object to be curved)
The easy way (it requires using a curve modifier.)

Since the first way really requires step by step or a tutorial, and is out of scope for this site, I'll give you the easy way.

Using a Curve modifier

Create your object that you want to curve, make it the length that you want it to be. Be sure it has plenty of vertical subdivisions or edge loops, the more, the merrier. (actually, just the smoother after curving.) This picture shows the mesh properly set up to be curved, notice the "up-down" lines, these are the loops I was talking about.

I know you didn't want to use curves, but Create a curve! in order to get something really nice without a lot of trouble, you need curves, and once you get used to them, they really aren't that bad.

Once you've shaped the curve just right you can re-select the mesh and add a curve modifier. isert the curve you just created under the Object parameter.

Very good! you now have a curved object: if it hangs off the edge of the curve a little, just mess with the location of the mesh.


Smooth brush destroys my mesh So i'm sculpting and, sometimes, specially after i made a big change in the surface with any other brush, the smooth brush completely destroys the geometry that was there. This only happens after i've set dynotopo and changed the mesh, and if i turn it off, it stills creates the same problem.
Every now and then if i enlarge the radius of the brush, it fixes it, but usually i have to take out any hard edge or lower a big bump that i made before and that seemed to have caused it. The weird thing is that it acts like that for the whole mesh and not just specific parts, and that sometimes it only happens when using my graphic tablet(as in the gif), but other times with both the tablet and the mouse.

It turns out, my pen tablet has the option to switch from Add to Substract, to do the opposite of what the brush was doing.
Whenever this happened was because I had it in substract mode, I didn't realize this because, in previous versions of Blender, Shift to smooth always smoothed stuff, but not anymore it seems.


2.8 Properties Tabs all disappeared and nothing I've tried from other answers works my little boy loves Blender, but the new 2.8 release just did something odd, he can't remember doing anything but the tabs that used to propagate the right-hand side panel no longer appear when clicking the model to modify it.

See picture...

Tried scrolling, there's nothing hidden, can't find anything else relevent to 2.8 so we are missing something.

Thanks very much in advance for helping a little boy and a noob father.

Thanks to all the help. I found a "Fix"? Although the video he's watching is exclusively in "Layout" tab mode at the top... simply switching to "Modelling" mode brings the editing properties all back - but I thought this was just a layout so haven't figured out why they are still gone. Certainly my boy has a lot my on-screen icons and properties now than the Blender guy in the video...

The video doesn't show this>??! See Pics (the update didn't do anything for this issue).

I spent over a day with this problem eventually taking bits from other results, putting them together, then investigating the few property tabs that I had still got I discovered that the Render tab had somehow acquired the Pin in it's top right corner. Un-pinning it brought back the rest of the property tabs.


Volume Absorption is only applied to the "top" of a mesh I am following the BlenderGuru tutorial of making a cup of coffee, but when I make the coffee liquid using volume absorption, the coffee only appears to absorb light from the top. When I adjust the view to the sideview, it still looks transparent.

Anyone know what I do wrong? Please see the image with nodes attached.

I am new to Blender, so I can't say I solve this problem (I am quite sure if the coffee cup is animated, the coffee liquid won't looks right)
, but I do discover what causes this problem.

When the scene setting is like the follow (the camera looking at the perpendicular to the light source), the side of the coffee mesh looks transparents.

I changed the scene setting like the below (the camera facing the light source)

Now the volume absorption works! the side of the coffee is now brown instead of transparent.

I am guessing this is due to how volume absorption works. If there is no light passing through the mesh to your camera (i.e. camera perpendicular to the light source), the volume absorption calculate that there is no light absorbed at all, meaning transparent. (but in real world, it should appeared darker, or something else, but not transparent).

Hope this makes sense, if you guys happens to know how to make it more realistic, please tell me. thanks!


where is the viewport shading in blender 2.8? i am trying to render my project in real time in blender 2.8 cycles but i can't change the viewport option and I can't find it  any help ?

The icons are on the bottom toolbar in the 3D View. You can't see them because the 3D View is too narrow, so they're getting cut off.
You can move the divider between the two 3D Views to the right to reveal the icons:

You can also can middle click and drag to the left on the toolbar to access the icons:


Why doesn't Volumetric follow the shape of Mesh in Eevee? So I was in the middle of making a ball-shaped smoke, but the volumetric effect didn't work following the basic shape. It remains cube in Eevee Blender 2.8; while in Cycle it works, but in Cycle it takes thousands of years for Render.

Eevee's support for volumetrics is quite limited.

From the blender manual:

  Eevee’s goal is to be an interactive render engine. Some features may not be there yet or may be impossible to implement into Eevee’s architecture without compromising performance.

Read: Eevee Render Limitations

  Volumes Objects

  Object volume shaders will affect the whole bounding box of the object. The shape of the volume must be adjusted using procedural texturing inside the shader.

What that means is that the volumetric shader will always be a cube or a cuboid.

As far as I know it is meant more for haze and atmospheric effects, so volume would be used on volumetric domains, not so much in detailed meshes made of smoke or dust.

Maybe someone that actually cares for Eevee can clarify.


Where can I get Blender test builds? I know that Blender.org provides downloads for official releases. I see on forums that people use newer versions of Blender. Where can I get newer version of Blender (nightly builds, alpha versions... etc).

GIT/Development builds:

The Buildbot:
There is a buildbot that builds from the git repo daily. You can get git (development) builds for all operating systems that blender supports here.
Compile from source:
Another option is compiling blender from source, see the wiki. While this may seem like a lot of effort, once its setup, it can be less trouble then having to continually download large files, and you can test new features minutes after they're committed.

Release candidates:

You can get past releases and current test-builds/release candidates here.

Linux:

There are some additional options for linux besides GraphicAll.org and the ones listed above.

Ubuntu:
You can use a PPA such as the irie PPA. (See this question on AskUbuntu for instructions)
Archlinux:
The blender-git package in the AUR


Superimposing Objects & Video I'm trying to add animated text banners (objects) onto an edited video via Video Sequence Editor. I've watched several tutorials on this subject, though every one I have followed has failed to work. Here is what I'm working with:

I've reduced the Opacity to make it clearer what I'd like to do. So far, adding the 'Scene' has been the closest to success. I've tried adding nodes, textured planes, etc. though none were successful. With nodes, I can for render only 'Scene' (Layer 4) or the edited video (Layers 1-3), but not both.

Blend. 2.78

I figured it out that in the render settings (with 'Scene' selected), I could set the Alpha to Transparent, then change the blend settings to Over Drop.


Where is the Feature output for the Voronoi texture node? Does anyone know how to find the Feature Output for the Voronoi texture in the shader editor? It didn't show any at all.

Feature Output determines which points are used to calculate the distance.
It's the one with F1, F2... values.
Keep in mind that Voronoi Texture node have changed somewhat between 2.8 and 2.83.


Change all metallic value with python I have a bunch of metallic materials that use the Principled BDSF, and I need to change all of them from a metallic value of 10 to a metallic value of 1. Can this be done using a script?

￼Shamelessly modified from:
Automatically change the properties of multiple materials
import bpy
for mat in bpy.data.materials:
    if not mat.use_nodes:
        mat.metallic = 1
        continue
    for n in mat.node_tree.nodes:
        if n.type == 'BSDF_PRINCIPLED':
            n.inputs["Metallic"].default_value = 1


Mesh only displays as wireframe? I'm using non destructive Boolean methods to cut into the mesh. When I duplicate the Boolean it only becomes into a wireframe. I tried deleting the modifier and also tried to convert into mesh from curve trying different options but cant get the solid mesh again.

I guess it has to do with the Bool Tool which automatically switch the display of the boolean object you're using to Wire. Go in the Properties panel > Object > Viewport Display > Display As and choose Solid (or Textured)


Snapping Bones to Bones (In Other Armature) I am trying to scale and position the bones of one armature to another. And, I was wondering if there was a way to snap the position of the bones in one armature to the position of the bones in the other?
Thank you for your time!

I was looking for the same. I saw the UE folks do this and was trying to do it without their plugin. They show it happening here... (https://www.youtube.com/watch?v=F9cTXzO8wq0&list=PLZlv_N0_O1gaxZDBH0-8A_C3OyhyLsJcE&index=4&ab_channel=UnrealEngine)
It's a bit tricky since your cursor has to be in the correct place...

In object mode, select both armatures.
Go into 'Edit mode'
Enable 'Vertex Snapping' (refer to image below to see where to find the button to open the menu. (enable rotation/scale here if you'd like to)
Select the bone head/tail that you would like to move to the other.
** Tricky Part here: Ensure your cursor is inside (or near) the source head/tail before you start transforming.
Press G to transform the position of the tail/head.
Moving close to the other armature tail/head should snap to it.

** Also note that, if you move the tail of one bone, you will likely have to move the head of it's connected bone too.


Mirrored (flipped horizontally) after rendering image or movie Everything looks great when orbiting 3D, the text on my texture boxes looks great using cycles.  But when I bake, or render a image or movie,... the image/text gets flipped horizontally.  I cannot find any help on this anywhere.  Here's hoping you'll help.
Here is a movie on vimeo showing my mirrored results...
https://vimeo.com/62238175

Maybe a UV problem.
Try to select the UV face that is flipped and press Ctrl+M to mirror, then press X or Y to select the mirror direction.


Create keyboard shortcut for an operator using python? How can I create a keyboard shortcut for a specific operator with using the python API?

Minimal add-on example using keymap_items.new() to register a new hotkey CtrlW in 3d View:
import bpy

bl_info = {
    "name": "Your Addon Name",
    "author": "Author Name",
    "version": (0, 1),
    "blender" : (2, 80, 0),
    "location": "",
    "warning": "",
    "wiki_url": "",
    "tracker_url": "",
    "category": ""
}

class OBJECT_OT_CustomOp(bpy.types.Operator):
    """Tooltip"""
    bl_idname = "object.simple_operator"
    bl_label = "Simple Object Operator"

    def execute(self, context):
        print (self.bl_idname)
        return {'FINISHED'}

addon_keymaps = []

def register():
    bpy.utils.register_class(OBJECT_OT_CustomOp)

    # Add the hotkey
    wm = bpy.context.window_manager
    kc = wm.keyconfigs.addon
    if kc:
        km = wm.keyconfigs.addon.keymaps.new(name='3D View', space_type='VIEW_3D')
        kmi = km.keymap_items.new(OBJECT_OT_CustomOp.bl_idname, type='W', value='PRESS', ctrl=True)
        addon_keymaps.append((km, kmi))

def unregister():
    bpy.utils.unregister_class(OBJECT_OT_CustomOp)

    # Remove the hotkey
    for km, kmi in addon_keymaps:
        km.keymap_items.remove(kmi)
    addon_keymaps.clear()

if __name__ == "__main__":
    register()

    # test call
    #bpy.ops.object.simple_operator()


XYZ Math Surface equations revision Is it possible to revise XYZ Math parametric equations without deleting the object and starting over?

If you're talking about reseting/applying global scale, rotation, location then you can press ctrl+A shortcut and select the needed option.


How can I fix my rotation issues of an object following a path? I have a project with an animated bird following a path. Everything was working pretty smoothly, but now when I get to a certain point on the path the rotation of the bird is messed up, and when I try to adjust the rotation it won't rotate correctly along the selected axis. I'll attach the .blend file so you can see what I mean. Any suggestions will be much appreciated!

.blend LINK:  https://www.dropbox.com/s/x8x13845d2bj5cm/bird.blend?dl=0

Simplified Bird and Circle Path.

Know that your final location and orientation is a combination of the displayed bird rotation and the effects of the Path Constraint [PC]
Choose correct origin for the bird. This might be middle of body. Perhaps near spine.
Remove all location and rotation keyframes for the bird for initial phase.  This eliminates competing animations. Fresh start.
For the initial phase your bird can start at the origin
Enable the Follow Curve option of Path Constraint [PC]
If need be choose correct initial rotation of the bird.  Typically in degrees one of 0, 90, 180, 270 in object mode on one or more axis.  You may want to keyframe this as a safe starting position at a known reserved frame number X.
Enable Fixed position in the [PC].  Set keyframes in [PC] for offset.
If the bird is always consistently tangent (lined up) to the curve you are golden.  If not allow your self one additional rotation keyframed on the aforementioned reserved frame number X.
Get the above steps to work. Archive File and consider more complex animations later.


Kind of "soft link" of objects between scenes? I want to reuse the object of one scene in another. So far, I found two possibilities, both with side effects I do not want:

Copy and paste from one scene to another. However, if I'll edit / correct the mesh in the first scene, I do not see the changes in the second scene.
Linking from one scene to another. This reflects the mesh changes, but also rotational changes. If I rotate the object in the second scene to lay it on the floor for presentational purposes, it also rotates in the first scene, where I actually want it to just stand around for modelling it.

Is there some kind of soft link which reflect mesh changes, but not rotational / position / scale ones?

You can use the 2nd method, linking your object to the other scene.

Link the object to the other scene as normal. Selecting that object (the one you want to be able to rotate but still be linked) navigate to it's 'Object' tab in the 'Properties' window and make it's object datablock a single user by clicking the '2':

Alternatively, you can press U> Object to achieve the same effect, which will make any of the selected objects a single user.

Clicking the '2' makes a copy of the transformational data for the object but leaves the mesh data, the vertices and faces etc as linked, as shown in the 'data' tab:

The '2' shows that the data is now being used by 2 distinct objects, with different transformations, whereas before it was acting as a single object, sharing both transformations and data.


How to hide the armature to do UV unwrapping? I'm new to Blender. I have made and rigged a character and want to do UV unwrapping to texture it but I don't know how to hide the armature to be able to do the next step. Please advise.

You could use one of two approaches to do this.

Layers
Object Hiding

Layers

This is what I would recommend.

Layers let you control at what level an object is "visible" much like a layer in a program like photoshop. You can enable or disable layers and move objects to different layers. To move an object to another layer you only have to use the M key by default

Simply select your Armature object(s) and hit M then you can move to any of the layers you want. The little orange dot in the layer selector shows which layer the active object is on.

You can read more about layers here and since you might be new, it is very good to understand how they make working with blender easier.

Object Hiding

If for some reason you cannot use layers, you can hide the objects you do not want to see while not moving them to another layer. You can do this by selecting the object(s) you want to hide and pressing H.

Once this is done you can no longer see / select the object from the 3d view. The object will still show up in renders.

If you want to see all the objects you have hidden, you can press Alt + H.

If you only want to unhide specific objects, you can use the outliner (the tree view in the top right) and click on the eye icon to unhide hidden objects.

You can also use other shortcuts to hide objects en masse etc. This post also details one way you can hide all objects EXCEPT the selected object

Comments:

You can use both object hiding and layers together but turning off a layer makes it get hidden from rendering.

Hiding an object but keeping its layer visible does not make hide it from rendering.


Object mode mesh different from Edit mode No modifiers, no shape keys or anything; it's just the starting cube. It's not showing insets I made.

You have hidden polygons
Press ALT + H to unhide ande then, delete all.

Good Luck


Why is mirror modifier not being applied symmetrically? I can't figure out why the mirror modifier is being applied to the face that left or right of one it should be

As far as I can tell my origin point is centered and my mesh is symmetrical.
I have not moved my origin point nor moved the mesh in object mode.

My guess that your mesh is symmetric, but the symmetry axis is rotated. for example you rotated your Mesh in object mode. I am pretty sure that you did something like that, because you presumably used the default 32 vertices number cylinder, and in that case 4 vertices must be aligned  to the coordinate axis by default, if you add your object to the center of your world, without tweeking the Add circe tool option... so it should look like this:

My hint:

Delete your extrude.

Apply Mirror.

Rotate your object (in object mode), to make the axis "cut half" the edges. Like this:

Apply rotation (Ctrl-a)

Recreate mirror modifier, and you good to go.

In the future for similar objects, you should rotate circles/cylibders like this if you wan them have symmetric handlers.The general formula for rotation for blender circle:

360/vertices_number/2 (if you use degrees. You can write it directly to the rotate property field)

(it will not work on your current object, because it is already rotated)


Add MULTIPLE actions to an armature I have made a direct interface with a Kinect2 sensor, via DLL, for MakeHuman. While recording, sensor data is buffered in an array.  Once recording has stopped, and an armature is made the active object, a button operation can transfer / re-target the data to the armature.

The problem is I cannot manage to get a single action, meaning there is one named armatureNameAction and another my name (with code & no keyframes) like this:

import bpy
from mathutils import Vector

action = bpy.data.actions.new(name = 'my name')

ob = bpy.context.object
bone = ob.pose.bones['K2-Root']
value = Vector((1, 1, 2))
bone.location = value
bone.keyframe_insert('location', frame = 1)

This can be fixed by not even creating an action & just assigning the name of armature the action like this:

import bpy
from mathutils import Vector

ob = bpy.context.object
bone = ob.pose.bones['K2-Root']
value = Vector((1, 1, 2))
bone.location = value
bone.keyframe_insert('location', frame = 1)

ob.animation_data.action.name = 'my name'

With this way, how does the person make another sensor session & add a 2nd action?

If calling key_frame_insert directly from a bone, the easy way, and it always writes to an existing action unless it needs to create it, then the answer is to just manipulate the facts on the ground.

In the simple 2nd example, you can simply assign the armature's current action to None, ob.animation_data.action = None.  These examples only have just one bone & frame though.  When I place that in the real code, there is also an empty my name.001 created. If I try adding ob.animation_data.action = actionto the first example, the same empty action is also created in real code.

Though that empty action would get removed on save / reload, it looks half-assed.  With some help from here, if you un-link the action, and rename after the new keyframes are added, you get one action every time.

import bpy
from mathutils import Vector

ob = bpy.context.object
if ob.animation_data and ob.animation_data.action:
    # save last action, so it does not get removed without user doing something
    ob.animation_data.action.use_fake_user = True

    priorAreaType = bpy.context.area.type
    bpy.context.area.type = 'DOPESHEET_EDITOR'
    bpy.context.space_data.mode = 'ACTION'
    bpy.ops.action.unlink()
    bpy.context.area.type = priorAreaType

bone = ob.pose.bones['K2-Root']
value = Vector((1, 1, 2))
bone.location = value
bone.keyframe_insert('location', frame = 1)

ob.animation_data.action.name = 'my name'


Infinite Tunnel Droste effect I've been looking at videos that create what is called Droste Effect
where an image contains smaller version of the same image and they spiral ifinitely into each other.

like Escher's Print Gallery

or

I've looked at the math behind this here but I don't know I would deform an image recursively to make it repeat itself endlessly,

There are a few videos creating this effect using a tool called Pixel Bender.

https://www.youtube.com/watch?v=CEauXI6fV2A

https://www.youtube.com/watch?v=9WHdyG9mJaI

https://www.youtube.com/watch?v=jrUFx0f_GR0

How can an image be deformed like on the reference the videos to create an infinite tunnel in blender?

here is a messy node setup that  could be turned into one  python node "I'll try to do that " :
this is the node setup

this is the node-group

the object index in the node-group should be that of the "object of interest", also the is object is unwrapped before.

finally here is a quick simple render :

*the UV and ID outputs of the node group are only added to ease hooking up more nodes sequentially


Why is it bad to Tonemap exterior scenes? Please excuse my ignorance (still trying to wrap my head around this)

First off, I have watched BlenderGuru, CG Cookie and read the BSE threads from TROY_S and others, and followed this comical thread along with going down the "rabbit hole" . I feel I have an ok understanding of this, but certain statements really confuse me.

In this post,

the OP says he would not use tonemapping for exterior scenes and keep it Linear? Why not for exterior?

how would you render a scene and keep it Linear without tonemapping? Would this be done by selecting "none" in the filmic looks?

I thought if you are using "Filmic" from Troy_S you ARE tonemapping while keeping it linear?

... Sorry the more I learn the more confused I get.

It's not.

Tonemapping is extremely common for exterior scenes, even outside the CG world. Before computers and exposure bracketing, photographers used graduated ND filters as a rudimentary way to tonemap the sky which is usually over-exposed compared to the rest of the landscape.

Tonemapping is an artistic choice, there are no rules for when you can and can't do it.


Can themes be exported and imported? If I create a theme, can I export it for import later or for distribution?

The themes are saved as an XML file under scripts/presets/interface_theme. You can manually navigate to there and grab the XML files.

Installing a theme is easier, you can use the install Theme... button in user preference panel.


Can I make character hold hands using contraints? Trying to solve a problem here. I've got two characters, each with an already animated walk cycle. I want them to be holding hands:

I tried doing by hand but the result is too jerky:

Is there some way I can constrain the child's hand to the adult's to get a smooth result?

Thanks!

This is not a perfect solution, but it meets my needs for this project.

Created an Empty
Applied an Inverse Kinematics bone constraint to the hand bones of each character.
Set the empty as the target in the bone constraint and the chain length to 3.

This snaps the hands of each character to a single location. The chain length ensures that only the arms of each character move toward the empty.


Weird line following my cursor when sculpting Why do I have this line following my cursor?

That's smooth stroke, it is intended to smooth out mouse/pen movement, you might have heard of it under a different name: lazy mouse.

Imagine it as tough your cursor is pulling the actual brush.

To disable go into sculpt mode -> tools -> stroke -> disable smooth stroke.


Character getting distorted while Parenting to bones I'm trying to teach myself how to rig for the first time and after finally getting somewhere with it, but my mesh gets distorted when I try to parent it to the bones with automatic weights. I don't know where else to go from here.

This is the mesh before Parenting.

Notice how the body and the legs are skewed and distorted.
I've removed doubles, and I've removed modifiers and still it gets distorted.

It might be due to the origin of the armature being different from the one of the model. Try setting both origins to the same point and then try it again.


Blender Denoise and Glare nodes I want to add a glare node to my render result but when I do that I can't use the denoise node, I tried to combine them with mix node but then it's only allowing to 50% of each node to take effect on the render.

I tried to save the render after denoise is applied and then open it in a new image node in blender and the connect it to glare node but it doesn't look good, looks a lot darker and I tried all the color spaces on the node and none of them gives the result that I want.

So it was a simple fix, just had to connect the denoise node to glare and then the glare to composite and now the image have a full denoise applied to it and also the glare effect that I wanted.


How do I apply a light/dark mask to a mesh? I'm not sure if this is something I should be doing in Photoshop or in Blender, but I have a file that looks like this:

It is supposed to darken or lighten the underlying color to create shading. I know how to apply transparency and normal masks, but I can't find an option for this one, and I haven't had any luck googling for it.

It is a bit difficult to understand what you are describing. I would have to assume you are using Cycles, and that you already have a mesh that is UV unwrapped to match the layout of this image.

If the above is true, you would "apply a light /dark mask"  by using a mix node set to overlay mode. You would plug your underlying surface into the top of the mix node, and plug this image into the bottom of the mix node. Overlay ensures it will lighten or darken as appropriate to your image. You would then increase the factor to get a level of mixture that you desired.

Hope that helps.


Why does rotating an object on its axes in a different order result in a different final rotation? As in the first GIF below, the result of rotating X first and Y rotating is different from rotating Y first and rotating X.
And like the second GIF, the result of rotating the Z of two objects first, then rotating X first, then rotating Y, and rotating Y first and rotating X are different.
Obviously, although the X, Y, and Z values of the object are the same, what causes the rotation result to be different depending on the rotation order? Is there a workaround?

If you go to the top middle of your screen you will see its literally called local. Change that to global and you should be rotating on the global x and y axis and z axis.
In the second gif the objects origin is at the corner of it (were the 3d cursor is) Fix this by selecting the object and right clicking then setting the origin to the geometry and it should be fixed.


Rotate texture at the middle of UV and without tiling distortion (MAX like) I need texture center to be in the middle of UV coordinates and make this possible
(gif video https://imgur.com/j24jLxi)
working in blender (gif video https://imgur.com/bZoOVEa)
this

to this

File scene with plane and texture packed
https://www.mediafire.com/file/e3vm7hn08ajo8ms/Tiling_example.blend/file

Object coordinate
Object* coordinate has 0 in the middle:

Notice how I apply a 50% scale, because Object coordinate goes from -1 to 1, so it's twice as big as UV coordinate going from 0 to 1)
Offset, then rotate
This is the worst solution. You can subtract .5 from your UV along X and Y, to make the middle have 0, and then add it back after rotating:

Notice how you could use simpler nodes instead of Mapping, like Vector Math > Add, but while we're at it...
Just use "Vector Rotate" node
And precise where is the center - the point around which you rotate:


Funny rotation differences between Quaternion wxyz and xyz Euler I am rigging my character.  The Central thigh bone has copy rotation of FK thigh control bone.  Pls refer the picture for clearer circumstances.  I hit R -> Y -> -90 to open the leg to test rig.  Then a puzzle ensues.

If I use Global orientation with Quaternion wxyz for rotation, the central thigh bone immediately misaligned.  Any minor change to rotation any attribute will realign central thigh bone with FK thigh control bone.

If I use Global orientation with XYZ Euler for rotation, the rig works fine.

I also find out that the rig works fine using any other orientation (normal, local, etc.) with Global orientation.

If I grab the FK thigh control and rotate it manually, the rig also works fine.

Window console has not shown anything funny.

What gives?
Is my file broken?
How can I fix it?

I would hate to redo all the works.

THX

I'd stick to the default setting - Euler XYZ. There may be nothing wrong with the quaternion button. Quaternion numbers are 'complex numbers' - I don't follow the concept, but they're 4D (ergo the W next to XYZ). That's probably mucking up calculations and data that were amassed and made to function in a 3D space.


How do I get a clean slate after every run of my add-on? So I have been working on an exporter as part of my Google Summer of Code project. As I am new to Blender add-on development, I was under the impression that my code would get a clean slate every time it ran, specially when the register / unregister methods were implemented.

Unfortunately my code has been exhibiting some very weird behavior! It is basically as if all the data structures are being cached by the Python interpreter, and all code is being executed several times.

As GSOC projects are open source, you can check the source itself on Github, but it is far from complete yet.

All runs of the exporter produce a debug log with some of the operations carried out. It also helps convey my problem more precisely. Here's the successful output after a run on the default scene. Now here's the incomplete output on the second run of the same scene. Even though it crashes, it is clear that all lines are basically duplicated.

For the record, I am using vscode with this add-on for development. Please let me know if any more details are needed for this question!

EDIT: Actually, my implementation was broken, but thanks for all the help given in this thread!


why N-Gons can subdivide some times and some times no? as far as i know n-gons cant be subdivide by adding edge loop but i discover that some times it can be :

i tried to make loop cut again but it doesn't done ,
i know it should good thing to cut Ngons sometimes but that make me wondering /: ?!

Going around the cube this way:

You have a continuous face loop, regardless of its ngon status, because the connecting faces just have one edge between them.

If we "unwrapped" the shape in the direction you're cutting it would look like this (I've only shown three sides)

If we went the other direction it would look something like this, with a couple extra verts:

And this is no longer a continuous face loop.  The loop cut operation will stop when it can no longer find a definite way to travel down the next face.
Looking at all the edges this cut could decide to go to:

I would say as human onlookers it's pretty clear where it should go, but programmatically (for the general case) it's probably a hard problem to solve.  The operation just stops when it can't find the next face in the loop.


How to apply a modifier in V2.9+ Why I can't apply mirror modifier?
Here's screen

Click on the top triangle to apply the modifier, or use Ctrl+A.
Remember, you need to be in Object Mode to apply modifiers.


How to disable All Face and Vertex modes when vertex painting? I know the options are available in older builds of Blender, and can be ticked in vertex paint mode, but I cannot find them in the current version. Anyone know how I can paint vertexes on specific faces only?

This option can be found beneath the 3D View. Its icon is a cube with a grid on it.


How to set glow in text object, with python? So, I want to make my text glows. Using python. Until now, I've scripted this, after reading some tutorials:

import bpy
def create():
    bpy.ops.object.text_add(location=(0, 0, 0))
    text_obj = bpy.context.object
    #'glow'
    scene = bpy.context.scene
    scene.world.light_settings.use_indirect_light = True
    scene.world.light_settings.gather_method = 'APPROXIMATE'
    scene.world.light_settings.passes = 2

    mat = makeMaterial("font", (1,1,1), 1.8)
    text_obj.active_material = mat

def makeMaterial(name, color, emit):
    mat = bpy.data.materials.new(name)
    mat.diffuse_color = color
    mat.diffuse_shader = 'LAMBERT'
    mat.diffuse_intensity = 1.0
    mat.specular_color = color
    mat.specular_shader = 'COOKTORR'
    mat.specular_intensity = 0
    mat.use_transparency = True
    #mat.raytrace_transparency.fresnel = 2
    #mat.alpha = transp
    mat.emit = emit
    return mat

if __name__ == "__main__":
    create()

Why this isn't working good?

Tks

The way you setup the scene, the glow is only noticeable if you have another object. It will not cause the 'air' around the text to glow.

Below is my test render when I run your script with a plane. I this what you want?

If you want the air around the text to glow, approximate ambient occlusion cannot give you that. You'll need to use the compositor.


Glass material rendered as dark grey I am trying to render a glass material on a cup. But it looks grey after rendering. Screenshot of the render. (https://i.stack.imgur.com/cNMEc.png)

The material details are as shown.Material details.(https://i.stack.imgur.com/H8Z84.png)

Your issue is with the render settings. By default, Eevee does not calculate Screen Space Reflections, effectively disabling translucent/transparent materials.

You have two options, change to the Cycles render engine, or stick with Eevee and enable Screen Space Reflections and Refraction


Rendering Issue - Tracked Video & 3D Object Composite When I render the scene, only the tracked video appears; the 3D objects do not render. However, the objects appear if I set my active view to rendered (Shift-Z). "Restrict Rendering" is inactive.

After rendering, this message appears:

  No Layers in Render Result

Might be an obvious one, but check your render layer setup and which layers your objects are on...

Also check your compositing node setup after rendering an image. I've had problems in the past when I accidentally moved objects to layers that were selected as a mask layer or Excluded layer.


Python: How to know how many objects are inside of the selection ? in this code

import bpy

def find_collection(context, item):
    collections = item.users_collection
    if len(collections) > 0:
        return collections[0]
    return context.scene.collection

def make_collection(collection_name, parent_collection):
    if collection_name in bpy.data.collections:
        return bpy.data.collections[collection_name]
    else:
        new_collection = bpy.data.collections.new(collection_name)
        parent_collection.children.link(new_collection)
        return new_collection

for o in bpy.context.selected_objects:
    P = bpy.context.selected_objects[4]
    P_collection = find_collection(bpy.context, P)
    new_collection = make_collection("Quick Particle 01", P_collection)
    new_collection.objects.link(P)
    P_collection.objects.unlink(P)

im trying to move the whole selection to a new collection
i only have a single little problem, for it to work, i need the number at the end of this code

    P = bpy.context.selected_objects[4]

to be the exact number of the number of objects inside of my selection -5..
so if i have 5 objects, i need [4]
if its more it dont work,if it less it doesnt work, and if its nothing witouth any braquet
like this

    P = bpy.context.selected_objects

i get an error message

so im searching to do something like that

    P = bpy.context.selected_objects[***   bpy.context.numberofselected_objects"   ***]

In Python indexing works from the beginning AND from the end.
So if you need the second to last object in a list:

somelist = [ "a" , "b" ,"c" , "d" , "e" ]
print(somelist[-2])

would print

d


How to create a animated silhouette? I am making an intro for 'The Tim Show'. The thing is I've only modeled a good head and that's mainly it.

The intro will be like shadows of a person, with a drill in a hand, etc. Look here at 1:07 on the earth. Here is an image of it:

(I do not want a globe/sphere, only on a screen)

But it will be with Blender (yes!!) and will not be on an earth. I may enhance it with some other stuff.

The thing is I don't know where to start and I need a fast solution as I am under pressure.

Thanks in advance

You can use a human mesh with a shrinkwrap modifier on a plane. Let me show you an exemple:

First if you want to use an human body you can create it with makehuman and import it in blender with all the skeleton. Then you can create the animation of your human.

After that you can add the surface where you want your silhouette to be. For the exemple I used a plane.

Now you can add the shrinkwrap modifier on your human.

Now it's time to render. I've done the render with cycle, in blender internal you have problem with the superposition of the mesh like this:

So here is the final render with cycle:

Here is the video example on youtube.

And of course it works with animation. Hope this can help you.


Blender model deformation when moving with bone I am a noob at Blender and I am beginning to learn the basics... I am attempting to rig a halo spartan for animation, and when I try and pair the helmet to the rig (rig I got online), and when I go to rotate/interact with the head bone, the Helmet deforms and the mesh gets twisted and weird... I have no idea how to fix this, I've looked everything up related to this issue but no luck... here are some screen shots and the file which I am working on... Any help is GREATLY appreciated!(I haven't rigged the visor yet)
EDIT: also the helmet has an internal head structure to it and when I move the head model with a bone(i.e rotating the head bone it or moving the rig), the inner mesh drifts and clips through the helmet model... how can I eliminate the mesh from drifting? thanks
EDIT: I have uploaded a new edit of the file which includes the model's bones that come with the model if that helps

FILE HERE:    https://drive.google.com/file/d/1pfldMmA9ICe0En3kVihqZ727_TIbnW5j/view?usp=sharing

Don't parent With Automatic Weight, because it will give influence to several bones and your helmet will bend, instead parent to > Bone: Select the helmet, shift select the armature, then switch the armature to Pose mode, you'll see that the helmet is still selected, and press ctrlP > Bone. Parent With Automatic Weight is good for organic objects, but for machines, robots, etc, use a direct parent to bone.


Cursor and Pivot point not centre of Object I have 2 objects in my scene. I'm selecting the shape which looks like a 3 pointed star and trying cursor to selected and cursor to active. But the cursor isn't right in the middle of the object from the middle section its halved non symmetric as seen in the measurements. But on the rectangle when I do cursor to selected or cursor to active the cursor is right in the centre. How can I get the cursor spot on in the centre of the 3 pointed object?
Thank you.

The object center is based on the whole area.
To find the vertical center, select only the highest and lowest vertices and snap cursor to them.
Origin is at the object's center, 3D cursor is at the 'vertical' center


How can I have an entire island move when selecting a portion of it? In the UV editor, moving an island when selecting the entire island works fine. I am trying to select a part of my island and move it to cursor (offset). Ofcourse, doing this would only move whats selected. I need the entire island to move, except have a certain part of the island be used similar to an origin, having the entire island move, but using a certain part as an origin. How can I have an entire island move when selecting a part of it? In other words, I am looking to create an origin in the UV editor (for a certain island).

Enable Proportional Editing in the UV editor, setting it to Connected and Constant. Then after selecting just move the island as close to the relevant pixel you can, ensuring the Proportional Edit is mousewheeled out (down on windows) enough to move the entire island.
If you need to be perfect, I guess move a randon, probably still-to-be-unwrapped vertex to the cursor with Snap>Selected to Cursor. The select your island, and with Proportional editing above, Change "Type of Element to Snap to" to Vertex (icon next to the Magnet). Assuming Snap during Transform is off, G to move your island, and if you hold Control, your island should snap to the vertex at the cursor when you get near.
Just remember to to move the "spare" / "cursor" vertex out again by a combination of inverting selection or some such.


Is it possible to set which material output node is used? It is possible to have more than one the Material output node. As far as I have seen, only one of them will be used. Probably the first. Can it be changed?

I often use a second simple diffuse shader to get the output of a node in the middle of the network. Kind of like a viewer node, but with a material. With a simple way to switch the active output node, it could be made lots smoother.

I bet there's no way as simple as Greg's addon, currently. If you still chasing for another possible answer, try using Add Shader, hit M to mute one to show another. (Select them both then hit M will do a quicker switch)

Personally, I would recommend Greg's addon. Whatever, if this is what you want.


How can I create a mask by baking? So I have a plane and an object, I want to create mask image: white where the object is and black where it isn't. How can I perform this? I'm searching for universal solution.

This simplest I have found is to assign separate material to them; one white emissive and one with black emissive, and then bake a texture with the Bake Type set to Emit.

You can also bake it from Diffuse if you already have black/white materials on them. You should then bake it from Color only.

Yet another way of doing this is to remove any backplanes, bake a Combined map (or any map BUT normal) and use the Alpha output of the baked texture as mask.

If you need to use the Compositing Editor to get the final image extracted from the image, you can use this setup:

Open the Compositing Editor
Add an Image node and select your baked texture
Add a View node
Connect the Image Alpha to the Color of the View node.
Open the Image Editor and select the View Node as texture
Save the image from the Image Editor.


Smooth brush is not working correcly I'm currently learning to use blender, this is my second project its a character, now my problem is that i have used the smooth brush before and already know how its supposed to work (at least without changing anything).

Now I haven't changed anything in the settings of the brushes (or at least not on purpose) here is my problem:

I'm currently sculpting some details on my character but when i try to smooth this:

It ends up like this:

Now the problem is that the smooth brush smooths some parts and others are left with little spikes that wont get smoothed out no matter what I try, I have dyntopo turned on and I already applied all modifiers to the mesh so there are no modifiers activated.

Like I said before I'm a beginner and I'm currently learning, I have tried to look online for answers but I could not find any, thanks ahead!

try this:

enable dyntopo, then in the options bar above smooth shading, enable relative detail, what relative detail does is that no matter how much zoomed in or out you are, the size of your strokes will be relative only to what you set in the size options of your brush.

next zoom very close to the part of the abdomen that you want to smooth, and smooth it with the correct sized brush, in theory, that should work.

it should also be noted that the more polygons you have in there, the more gentle the smoothing will be, you can read more here:

smooth brush is destroying my model,what is happening?[SOLVED]

sources for my claim:https://www.youtube.com/watch?v=tZnUgt659oI   [at the 14:15 minute mark]

hope it works.


How to delete face that doesn't have vertices As below, I deleted some vertices and now I have a face (with a strange, dark orange partial outline) that doesn't have any vertices. I'm unable to select the face or manipulate it in any way. How can I select it and delete it? Thank you!

As indicated in comments, the face you're trying to edit belongs to a different object than the one you're editing.

The dark-orange outline indicates that there were multiple objects selected when you edited Edit Mode. If you try selecting multiple objects, you'll see that the last one is outlined in light orange, and all the others are in dark orange. That highlighting remains on the earlier objects when you enter Edit Mode.


Some vertices stay in their position when rigged I have a model which has been rigged for all of the body parts. However, the hair (which is a seperate model from the rest, meaning it can't be a mess up from that) has a couple vertices that decide to just stay there when animating my object. Here is an example of what it is doing:

I have tried:

Weight painting the hair

Makes her hair fall from her head at end of animation

Making the model one whole mesh

Yields same results, no effect whatsoever

Sorry if this is a duplicate, the other questions' answers did no help, as seen by what I have tried.

There are only two reasons that vertices don't follow the bone you expect them to.

They aren't weighted to that bone
They are ALSO weighted to ANOTHER bone

Not only do you need to make sure that those verts are weighted to the right bone, but you need to REMOVE them from any other bones. That's literally all there is to know about bones and weights.


Render light hitting an object, but not the object itself I am creating an overlay for a video clip. In the overlay, there will be a light emitting object. I want this light to affect the subject in the video, but not the entire surface of the video clip. My plan is to model the character in the clip and then render only the light hitting that model. I've not found a way to do so. Simpler version. I have a cube and a plane. The cube emits light. I only want the light to show on the plane and not the plane itself.  I have tried for hours to no avail. Any ideas?

After reading the answers, I tried more and this is what I came up with. Pretty close.

Renders as:

Difficult to show what I'm looking for without being able to do it.

Depending on whether or not you plan on simulating the materials of the subject, perhaps a setup like this would work:


Animation rotation of an object around another boject's fixed vertices I have this landing gear bay doors that I am trying to animate with a simple rotation to open at a 90-degree angle.  The bay doors are a separate object from the plane. The pivot point is where the 3d cursor is.

However, when the rotation takes place the main vertices and edge of the landing bay doors are totally off from the ones on the plane they should rotate around.

Is it possible to make the bay door rotate around the vertices and edge between them as indicated in red in the first photo?
Thanks for the help.

Yes this is possible.
It helps to be aware of a couple of things.

You can rotate an object around one of the 3 main world axies, by pressing R and then either X, Y or Z.

You can rotate an object around one of its 3 internal axies, by pressing R and then either X, Y or Z twice. (if you tilted an object a bit the world axies and the internal axis no longer align)

In order to rotate your bay door object around the red highlighted edge, you have to place the origin (a pivot) somewhere on this edge and align this edge with one of the 6 aforementioned axis and then make this orientation it's normal state, so to say, by applying the rotation.

So select your door in the 3D viewport, rotate it in a way so the red edge is parallel to a world axis (the X-axis for instance). Then (also in the 3D viewport) go to Object > Apply > Rotation.
Lastly rotate and move it back into its place on the plane. Now if you press R and then X twice, the door should rotate around the red edge.


Change Viewport's Orbiting Axis While Sculpting I am learning how to sculpt in Blender with a Wacom tablet. I'm finding that orbiting the viewport so a plane of mesh is at an ideal angle allows comfortable and ergonomic strokes to be made with the Wacom tablet. But some planes are at such angles they are very difficult to orbit the viewport an angle to make an ergonomic sculpting stroke.

This problem would be solved if I could (on the fly) cause the viewport to rotate on a custom xyz coordinate. Additionally, it would help if I could invert the x,y,or z. axis to gain additional ergonomic angles.

How do I do this with existing features or add-on? Or how about a solution that will achieve the desired effect?

In this screenshot the middle bar of clay has a diagonal stroke going from left to right. I need to orbit the viewport so each face of each other bar of clay is perpendicular to the user to make the same kind of stroke. Making the all planes of the first and third bars of clay perpendicular to the viewer seems impossible. Therefore my question.

A workaround would be to parent a camera to an empty, as follows:

Then, in the viewport snapping settings, enable face snapping and check Align Rotation to Target.

After doing this, dragging the empty around will snap the camera perpendicular to whichever face your cursor is on.

Setting the transformation orientation to Local will allow you to transform the empty relative to its own coordinate system.

Additionally, you can enable the visibility of gizmos to be able to easily rotate the empty:


Working with lower resolution in compositor viewer? I am Compositing a 4k image and when viewing it is very slow,so I want to work only with 1k viewer not the full 4k,but still have the same resolution when final render.

Scale Node

Something I do is put a 'Scale' node (Shift+A > Distort> Scale) just after any high-res image I want to reduce, setting the scale type to 'Render Size'. This will mean that any inputs will be scaled to your output resolution, set in the Render panel.

Using this method you can then reduce the render size to 50% using the resolution percentage property in the render settings and the compositor will reflect that change (though the compositor may only update to the new resolution when the frame is recalculated).

Here, I have the scale node after a 4k image, but with the resolution percentage set to 50% I only do the compositing with a 2k image, meaning the blur node is processing less pixels and will be faster.

When you want to do the full render you can just disable the scale node with M, which 'Mutes' the node or set the resolution back to full. Other scale node types will also work, instead of 'Render Size', this is just my preferred method.

Note: It is important to put the Scale node directly after the input image/movie so all the compositing is done on the low resolution image. Having the scale node at the end of the node tree would have no effect as the scaling would be happening after all the intensive compositing of the node network is computed.

Compositor Quality

You can also set the 'Edit quality' of the compositor to 'Low' in the Performance area of the Properties menu (N) in the compositor.


What is the fastest and easiest way to add a vignette in the compositer for Cycles? Poking around to find an easy vignette effect, I constantly run into seemingly unnecessary node setups. Six or seven nodes to add a vignette? An apparently really simple effect, this seems a bit much.

For simplicity, it just has to be circular (or oblong since 16:9) vignette. Doesn't need to have fancy options, just needs to work and be simple.

I usually do something like this:

It doesn't take too long to setup (three nodes), and it's provides a high degree of control:

The aspect (or even rotation) can be controlled via the settings of the Ellipse Mask* node.
The softness can be controlled with the Blur node
The amount of influence can be controlled via the mix node factor.

For a more automated solution
You could try something like this (click for full size):

This can be grouped into a single node (and included in your startup file) with very simple controls:


Extract sequence of frames from imported MP4 - scripted? I would like to extract a sequence of images files from an imported mp4, ideally using a script. I'll then analyze the images with python to start extracting cues and other information, so they don't necessarily need to be absolute best possible quality.

For example:

frame_numbers = range(15*60*24, 30*60*24, 96)

returns 225 frame numbers between 15:00 and 30:00 at 24fps.

Can this be scripted?

If not, what is the quickest way to do this manually? (ouch!)

You can do this using the compositor.

All you need is to prepare a simple node setup where you have a Movie Clip (Input) Node connected to the Composite (Output) Node. Load your video into the movie clip node, set a few small params in the script below (namely the output folder where you'd like to save the extracted frames and the frame range), and run the script.

The script will copy the video dimensions and set up your render settings accordingly (but will not alter the output file format).

import bpy
from os.path import join

S = bpy.context.scene
n = S.node_tree

vidNode = n.nodes['Movie Clip']

# Set Render Settings dimensions according to video
S.render.resolution_percentage = 100
S.render.resolution_y          = vidNode.clip.size[1]
S.render.resolution_x          = vidNode.clip.size[0]

# Render desired frame numbers ( UPDATE THESE AS NEEDED )
start = 5
end   = 200
step  = 3
frame_numbers = range(start, end, step)

outputFolder = "C:/tmp/test"    # <=== Update this
for f in frame_numbers:
    S.frame_set( f )
    fileName = str(f) + S.render.file_extension
    S.render.filepath = join( outputFolder, fileName )
    bpy.ops.render.render( write_still = True )

Copy this to a new text file in the text editor, change the values in the outputFolder variable and the start, end and step for generating frame_numbers, and press "Run Script".

If you'd like, you can also automate the creation of the node setup and load the video to the movie clip node; there are several nice answers here in StackExchange showing how to create and manipulate nodes via python.


making an umbrella in blender I am trying to make a material for the umbrella cloth. They have a specific sheen and reflective nature almost like silk and they tend to stand out from other type of clothes. I've been trying to achieve such a look but, I am not very good at materials and no matter what I tweak, it either looking rubbishly rubberish or not like an umbrella cloth material.

Here's one with general reflective surface which looks too smooth and not umbrella like:
I used IOR of .95 for this:

I searched up that umbrella was made of nylon and it's IOR was 1.5 so I put that and, well:

The first one obviously looks better, but not close to an umbrella material but unless we view it from a reflective angle:

Please provide me insight on creating this umbrella material which looks most realistic and physically correct.

I've attached the .blend file with the hdr.

If the Sheen effect is not enough maybe you should plug an Input > Layer Weight > Fresnel in the factor of a Mix between a Glossy and a Diffuse (or a Principled BSDF). To give transparency mix with a Translucent node before the end, the fabric will only seem transparent if you face the light source. Also maybe you should use a Wave node to create a discrete polyester fabric texture (just some parallel stripes).


How can I break a mesh into pieces? I've puchased a big interior scene from a 3d marketplace.

To optimize it in Unity (using Occlusion culling), I need to break the meshes into pieces, without modifying the structure.

Is there any blender command to do this?

In Edit Mode you can mark the polygons you want to separate and press P , then Separate by Selection.

Pressing L while hovering over a mesh in Edit Mode will select connected mesh parts.


How can I manually assign individual vertex UV coordinates? I've been learning a great deal about the various sophisticated ways to assign UV coordinates in blender, including unwrapping, seams, etc.

However, sometimes for simple tests it would just be so much faster if I could just write the UV coordinates for each vertex manually. Is it possible to do this?

You can edit the uv manually in the UV/Image Editor.
After marking seams and unwrapping, open up the UV Editor.
If you check Normalized, you can select vertices and input their coordinates in the range of 0 - 1.
When you check the Keep UV and edit mode selection in sync button , the 3D View selection is the same as the UV editor selection.
You could select vertices in the 3D View and input their uv coordinates in the UV editor.
Note, that you can also use the standard select, grab, rotate and scale tools in the 2D space of the UV editor.


Where are the rigid body tool buttons in Blender 2.80? Due to changes in 3d view port interface it's hard to find tool shelf menus in Blender 2.80. I do not want a shortcut for the Rigid Body Tools -> Copy From Active button, but instead the new position in the 3d view port in 2.80. I want this because I think that keyboard shortcut may be harder to remember than a button position after a long time.

You can either press space to pull up the list of commands you can input and type in rigid body, which will give you the option to copy rigid body settings, or you can follow the instructions on the screenshot.


Difference between Write Normals and Smooth Groups option in export .obj? Hi its just a simple question, whats the difference between those two? its sound like they do something similar, but in which case should i use one over the other?
Also if i can get a good explanation of those two would be great.

(i ask this looking to make some assets from high to lowpoly and baking in xnormal, so im using auto-smooth sharp edges, etc)

Thanks!

Write Normals does what it says - it write actual normals (face corner ones, i.e. one normal per face and per vertex). This is the most powerful and precise option, since it not only allows support of sharp edges and smooth faces, but also advanced low-poly tricks used in games and architecture, like 'rounded' edges etc.

Smooth Groups are a simplified version to store some non-uniform shading, it defines groups of faces that form a smooth surface. Meaning, edges between faces of a same group are smooth, while edges between faces of different groups are sharp.

Which one to use is mostly a matter of “what is supported by target application(s)”, though I would recommend to try normals first, since they allow more possibilities.


How to load a big number of maps and assign them to variations of a material? I've created a certain number of book cover textures (with their respective roughness maps) but I really don't want to create a material for every book and then assign their respective textures manually. I'm talking of hundreds of books. There's a way to do this automatically?

Working with you having some structure setup with your naming, let's say you have an object called "book1" and you have images "book1_diffuse.png" and "book1_roughness.png" you can create a material called "book1" that uses both images and then assign the material to the object.

import bpy
from glob import glob
import os

# adjust this to point to your texture directory
# can start with // to refer to the current blend file dir
texture_dir = '//textures'

os.chdir(bpy.path.abspath(texture_dir))
diffuse_imgs = glob('*_diffuse.png')
for img in diffuse_imgs:
    mat_name = img.split('_')[0]
    mat = bpy.data.materials.new(mat_name)
    mat.use_nodes = True
    m_nodes = mat.node_tree.nodes
    m_links = mat.node_tree.links
    diff_node = m_nodes['Diffuse BSDF']

    imgnode = m_nodes.new('ShaderNodeTexImage')
    imgnode.location.x = diff_node.location.x - 200
    imgnode.location.y = diff_node.location.y
    bpy.ops.image.open(filepath=img)
    imgnode.image = bpy.data.images[img]
    m_links.new( diff_node.inputs['Color'], imgnode.outputs['Color'] )

    roughnode = m_nodes.new('ShaderNodeTexImage')
    roughnode.location.x = imgnode.location.x - 200
    roughnode.location.y = imgnode.location.y - 50
    roughimg = mat_name+'_roughness.png'
    bpy.ops.image.open(filepath=roughimg)
    roughnode.image = bpy.data.images[roughimg]
    m_links.new( diff_node.inputs['Roughness'], roughnode.outputs['Color'] )

    uvnode = m_nodes.new('ShaderNodeUVMap')
    uvnode.location.x = roughnode.location.x - 200
    uvnode.location.y = roughnode.location.y - 100
    uvnode.uv_map = 'UVMap'
    m_links.new(imgnode.inputs['Vector'], uvnode.outputs['UV'])
    m_links.new(roughnode.inputs['Vector'], uvnode.outputs['UV'])

    bpy.data.objects[mat_name].active_material = mat

You can easily expand that to include any number of image textures for each material and add in a mix and glossy node if you wanted. You can find the node types you can use listed here.

If you have a random number of book objects, you could create the materials and add them to a list as you go, then go through the list of objects and pick a random material to assign to each.


Add a transparent image on top of a material [duplicate 2] I read the answer on the link on how to add transparent images on top of materials (Add a transparent image on top of a material ). This works beautifully in v2.79b.

This technique does not seem to work in Blender 2.80 anymore (I am using the very latest Mac version from Dec 20). The transparent image is also shown on the part of the mesh, which is not UV unwrapped. Is this a bug in v2.80? Or does v2.80 require a different approach?

What is really odd is the fact, that if I open in v2.80 a file created in v2.79 created, it shows up correctly.

Thanks for any advice!
Chris

Edits: screenshots and link to blender files added

https://www.dropbox.com/s/4kh40l870lbj96x/Ninja.zip?dl=1

UPDATED
I totally misunderstood your problem in my first answer so here is an update.
Your problem wasnt the transparency obviously, but the UV map itself.
As I checked your file (ninja28) It was like having two UV maps one over each other or maybe just overlaps on the same channel. I dont know what caused this, but if you did a remapping (even by using the mapping node or unwrapping the mesh again - I did both) it should work fine.

And Here is your (edited) file:


How to render only a mist pass I have spent a long time rendering an animation that I do not want to redo. I also want to render a mist pass though. Is there a way to render only the mist pass without rendering the original images? Sorry if this is a dumb question, it's just that in all of the tutorials, they show how to render both the original image and the mist pass.

I guess you could enable the mist pass, and in the compositor, Ctrl+Shift+LMB to view the mist pass and you'll get the viewer node. Press N to open the side panel and in the Item tab there is an option to save that as an image. [the viewer node has to be selected in the last step].


Why do grey faces appear on inset faces after using the knife tool? When I use the knife tool with angle constrained on an inset face it leads to these weird grey patches appearing on the face and I don't know what they are.

Is there any way to use the knife tool on an inset face without this happening?

Before simple knife cut:

After simple knife cut (highlighted):

It looks like the inset face has some bad geometry. The right-most edge might not actually be a boundary for the face. Try deleting the face & remaking it.

If that doesn't work, breaking up the N-gon into quads might help.


Why keyframed animation of linked object is not saved? I've Objects I linked from one file to another. When I make keyframes, save, then revert, the keyframes are gone.
So I copied the Objects to a fresh project.(I used two blender windows, that's considered appending still?) Then linked to a new project and it worked.
Can anyone tell me the difference between these files?
Broken File
https://drive.google.com/file/d/15WJkl-9PXkAo9BYnJF6GqM5l9vsFl4OR/view?usp=sharing
Working File
https://drive.google.com/file/d/1gy5Eo0AJcIGgfwd-CFvrwWk1HopLAUjX/view?usp=sharing
A video to help understand.
https://drive.google.com/file/d/1QGfcNyjZzMhZYZW2YmG5dKUAsSdK8pzF/view?usp=sharing

Files differs in more aspects, but one that cause saving the keyframes is your "CRUMPLE" action saved in your "broken" file.

There is several ways to fix it:

Delete this Action in your original file before Linking or
Manually set Make Library Override by right click on item in Outliner of the file or
Go to Dope Sheet editor switch to Action editor and click on chain icon to make it local or click on X icon to delete Action

Note: When you use "Link" operator (to bring some elements from another blend file) you can't modify them. For that blender use Library Override to make it happen. Any linked element in Outliner that is linked from external directory is using "chain" icon to indicate that. To be able to manipulate with linked object you have to Add Library Override, that creates something like information layer that stores changes from original.
I have never used Library Override before so I'm not experienced here ... but for some reason Actions and Materials are kept Linked for Make Library Override Hierarchy command by default. If it is a bug or expected behaviour ... I don't know (probably in common use you don't want to modify those). Anyway as I wrote you have to delete or Override specific items manually.


Pressing Ctrl Alt 0 is not working for me I'm learning through Blender Guru's videos and he said press ctrl + alt + 0 and it's not working for me. And even when he sculpted the donut I did not quite understand how to do it. Anyone know? Maybe there is another way?
https://www.youtube.com/watch?v=ZTxBrjN1ugA&list=PLjEaoINr3zgEq0u2MzVgAaHEBt--xLB6U&index=7

Press Ctrl+Alt+Numpad 0. It's important to use the Numpad 0 not the normal 0 on the upper key row.
If you don't have a number pad you can press F3 to open a search box (or Space - depends on preferences that you have set). There, search for the command 'align active camera to view'. Ctrl+Alt+Numpad 0 is the shortcut for it and listed there, too.


remove poles from sphere? hello is it possible to remove these poles on the wireframe and somehow structure the wireframe differently? ive tried deleting faces but it still draws the looks to the pole of the modelled sphere.
my aim is to have the object in a wireframe but have it look even and smooth without drawing the viewers eye to one part of the object.
does anyone know something?

Use the "Remesh" modifier.
Play with the settings until you get the level of detail that you want.


fur of cube going through mesh I am making a simple fur softbody simulation, in which the object falls to a stair in a satisfying manner. When i play this, the fur(generated through particles) seems to go through the mesh of the stairs.
is there a way to make the hair particles collide with the mesh?
when i enable hair dynamics the cube intersects with the stairs. like this:

Yes. Hair particles do respond to the Collision physics option. However, if you have Collision on the cube already to keep hair from going through it, it’s margin may cause the hair to stick straight out despite the stairs.
As a sidenote, Rigid Body and Collision can coexist.


Do "no cached" simulations give the same result in multiple computers? If a file has no disk cache and is rendered multiple times in multiple computers.. Does the physics simulation give the same result in every computer every time? (same file and not changin' the seed)

EDIT

Rendering with GPU and then CPU on different file locations gave same result.

Rendering on sheepit renderfarm splitting the frame into 8x8 tiles and so rendering on several different computers, gave corrected and same results.

If all the properties of a physics item are the same, then yes. Physics will work the same way everytime, if there is no dynamic wind simulation in your scene or something. Its blender, not real life.


Updating a 2.7 script that uses frame_current to work with 2.8+ There's a script I find very useful that works in 2.7x that is no longer working in 2.8x, 2.9x. I want to update it to work with current Blender versions. The script takes an object and makes a duplicate of it where it would be at each frame, applying mesh deformations. It seems it stopped working because of these Python API changes that came with the new Collections system.
The script that works in 2.7x was authored by CodeManX:

import bpy

scene = bpy.context.scene
frame_current = scene.frame_current

r = range(scene.frame_start, scene.frame_end + 1)
l = len(str(len(r)))
obs = []

for f in r:
    scene.frame_set(f)

    for ob in scene.objects:
        if ob.type == 'MESH' and ob.name.startswith("model"):
            me = ob.to_mesh(scene, True, 'PREVIEW')
            new_ob = bpy.data.objects.new("%s_frame%0*i" % (ob.name, l, f), me)
            new_ob.matrix_world = ob.matrix_world.copy()
            obs.append(new_ob)

scene.frame_set(frame_current)
for ob in obs:
    scene.objects.link(ob)
scene.update()

I messaged the author of the original code last week, but it appears he is not so active on Blender SE these days, so I'm not holding my breath for a response. Besides, maybe in the process of trying to fix this I can learn more about how the API works.
According to the API changes, I replaced scene = bpy.context.scene with layer = bpy.context.view_layer and that resolved one error. But now I am trying to resolve this one:
AttributeError: 'ViewLayer' object has no attribute 'frame_current'
This page of the Blender Manual still references scene.frame_current. Is this manual page outdated? Or am I misunderstanding and we can still use scene in certain cases?
This is my work-in-progress modified script, partially fixed for 2.8+:

import bpy

layer = bpy.context.view_layer
frame_current = layer.frame_current

r = range(layer.frame_start, layer.frame_end + 1)
l = len(str(len(r)))
obs = []

for f in r:
    layer.frame_set(f)

    for ob in layer.objects:
        if ob.type == 'MESH' and ob.name.startswith("model"):
            me = ob.to_mesh(layer, True, 'PREVIEW')
            new_ob = bpy.data.objects.new("%s_frame%0*i" % (ob.name, l, f), me)
            new_ob.matrix_world = ob.matrix_world.copy()
            obs.append(new_ob)

layer.frame_set(frame_current)
for ob in obs:
    layer.objects.link(ob)
layer.update()

Any help would be greatly appreciated. And if it can explained in a general way that may apply to others having problems updating a 2.7 script, or specifically those wondering about how frame_current has changed, that would be great.
Finally, one possible hint of new syntax is in this answer where the author has crossed out frame_current = 1 and replaced it with frame_set(1) ...unfortunately my logic of trying frame_get() did not work.

Updated script.
All changes here have been well documented.
Getting the updated mesh has changed.
How do I get a mesh data-block with modifiers and shape keys applied in Blender 2.8?
Scene update has been replaced.
What is the replacement for scene.update()?
Setting the frame is still done the same.  (frame_set is not a member of ViewLayer.)
Linking object to a scene has changed.
link new object to scene with python in 2.8
View layer objects has no link method.
revised script.
import bpy
context = bpy.context
scene = context.scene
dg = context.evaluated_depsgraph_get()

frame_current = scene.frame_current

r = range(scene.frame_start, scene.frame_end + 1)
l = len(str(len(r)))
obs = []

for f in r:
    scene.frame_set(f)
    #dg = context.evaluated_depsgraph_get()
    for ob in scene.objects:
        if ob.type == 'MESH' and ob.name.startswith("Cube"):
            ev_ob = ob.evaluated_get(dg)
            me = ev_ob.data.copy()
            new_ob = bpy.data.objects.new("%s_frame%0*i" % (ob.name, l, f), me)
            new_ob.matrix_world = ob.matrix_world.copy()
            obs.append(new_ob)

scene.frame_set(frame_current)
for ob in obs:
    context.collection.objects.link(ob)
context.view_layer.update()

Note haven't tested this thoroughly, re how often to evaluate the depsgraph, uncomment #dg = context.evalua.... to see if result differs when it is evaluated on a per frame basis.


Need help with perspective matching I love this painting by Ed Ruscha, and wanted to created a 3D tribute to it.

The idea seemed simple enough, but as I set out to do it, I had a lot of trouble getting the perspective to match. I even tried to using the BLAM add-on, which got me close, but I still can't seem to get the z axis lines of a rectangular mesh to line up with the painting. See the screen shot below.

Am I missing something obvious? or could it be that this painting is somehow an illusion, and impossible realistically model in 3D?

Any advice would be greatly appreciated :)

You can align this pretty well. The picture below is a rough result but it matches somewhat accurately.

From Haunt's trick bag:

Put the camera parallel to the ground. Switch on center guides in the camera settings.

Use your image as background image for the camera and shift it so that the floor rests with the center line.

Place a cube, also parallel to the ground, with its corner on the upper front corner of the roof. Distance doesn't matter too much. Put the cube's origin on this corner.

Rotate the cube around the z axis to roughly fit the angle. you can lock y and x to prevent errors. But the cube probably won't fit right away.

This result means, the focal length is too small since distortion is too strong.

Now adjust the focal length of the camera. I did this by animating it and switching frames with the arrow key. Re-align and re-rotate the cube around z until it matches perfectly.

When cube rotation and focal length match up, parent the camera to the cube and reset the cube's rotation.

Now you can freely move and extrude along the main axes and build your scene.

To match the pillars, finish the roof and place the top of the pillars at the exact height of the roof so it touches the underside in front view. Back in Camera View, move the pillar with the Z-axis excluded: G-SHIFTZ

At last, you need to tilt your camera up so you can make the image smaller and the floor rest at the bottom of your image.


Smooth shading and colored shadows When I set the shading of a mesh to smooth, the shadows on the mesh are always black when rendered, but I need them to be blue. When I set the shading to flat the color of the shading turns out fine. Is there a way to make smooth shading not black?

The person is set on flat and the scarf is smooth. I'm using Blender Internal.

I think the most easy method is to set Ambient Color in the World tab.


How do I edit video with blender I have never edited a video in the VSE. What is the least necessary to set up for editing in the VSE? I already have 3 mp4s in the VSE but dont know where to go from here?

I am trying to make one video from 3 parts.

All you have to do is drag and drop each clip so they are right after each other in the correct order. Then make sure the length of your animation is the same as the length of the 3 clips (you can set the frames in the render tab of the properties panel). Finally, select your output format (output panel of the render tab) and render the animation. If you have nothing else in your scene it should render very quickly. If you have anything else in your scene, the VSE will override everything in your scene and the final animation will be only what is in the VSE.


How to bake object with cloth simulation and subsurf (not applied)? Having trouble using .mdd method I need to transfer Blender scene with cloth simulation to Maya and Houdini.

In addition to cloth simulation, I used subsurf (not applied), after cloth modifer. And if I apply the subsurf, the cloth simulation will change, while I need to export to Maya an object with exactly the same animation that I have now.

I have used this method to export .mdd: http://blenderartists.org/forum/showthread.php?387461-Bake-Cloth-to-game-engine

and I faced a few problems in the process. I used a simple plane with cloth sim to demonstrate them:

1) If I export .mdd of an object with a cloth simulation but WITHOUT
subsurf, and then, after export, remove the cloth simulation and
import .mdd - everything is OK, but the object increases in size:

Before importing .mdd:

After removing cloth sim and importing .mdd:

2) If I export .mdd of an object with a cloth simulation AND WITH
subsurf (not applied), and then, after export, remove only
clothsimulation and import .mdd - I get a highly distorted object.
And even if, after export, I remove them both - cloth simulation and
subsurf, and then import .mdd - the result is the same:

I exported as .mdd this model with cloth sim and subsurf (not applied):

This is what I get after removing cloth sim and importing .mdd:

And the same result, if i remove both, cloth sim and subsurf before importing .mdd:

3) And the third problem is that I can't apply subsurf to the object
with the shape keys, so even if I did not have those problems, which
I wrote above, I could not apply subsurf thereafter.

How can I fix these errors? I really need to export my work to Maya.

Thank you very much in advance!

Enable the .mdd file importer / exporter addon:

Select an object with the cloth simulation and subsurf (not applied). CTRL + A - apply rotation, scale and location. Note that if some other objects, which are parented (or vertex parented) to that object, after applying operation, they may change their position and rotation. To avoid it, unparent them (ALT + P - Clear Parent), before applying, then apply rotation, scale and position, and then parent them back.
While the object with ththe cloth simulation is selected, export the .mdd file. Export may take some time.
After  export - remove the Cloth simulation.
Unparent (ALT + P - Clear Parent).
Apply subsurf.
At this stage, I usially re-applying rotation, scale and position, just in case - (CTRL + A).
While the object is still selected - import .mdd file.

Play the animation, or select a different current frame to update the final result. Note that the shape key animation rather increases the size of the project.

Many thanks to  Mr Zak, m.ardito from blender.stackexchange.com and to Richard Marklew, benu from blenderartists.org for their help in finding solution!


Blender Game Engine - Trigger something to happen in the future I'm somewhat new to BGE.  I've read some doco and played around a bit.

What I want to do is have an action trigger an event that happens in the future.  The task I was working on was to make a button that moved inwards a little when it was clicked (pressed), but then it popped back up again some time later.

I have no trouble moving the button-block down when activated by the mouse sensor, but I'm not sure how to get the button to move back up again (i.e.: "un-press" itself) after a short time.

The common form of this problem, is how to trigger something to happen in the future?  For example: how does one make an automatic door that opens when triggered, but then closes itself a few seconds later?

So far I've looked at all sorts of logic blocks, and python programming.  I'd really like a "Delay Controller" so I can catch the sensor-action, delay for /N/ frames in the controller, then invoke the actuator/whatever.  Using this idea, I could trigger both the door opening and closing (with delay) at the same time.

The only way I can think to do this is to run a python program every frame and check on counters or the system clock, etc.  But this doesn't feel like the correct approach for BGE.

There are many ways to implement "event in future".

The basic concept is you start something that takes a while and triggers an event later.

Animation based

This is pretty common as it starts a process and it presents progress to the audience. The animation is the cause rather than the effect.

When you play the animation with the action actuator (and it does not run in an endless loop) you can measure the end with the actuator sensor.

Be aware it measures when an actuator is active, but you want to know the opposite. Also keep in mind any actuator will start deactivated that will trigger the sensor too.

Counting frames

This is also a common practice. It provides you full control when to start and when to end. Unfortunately you have to implement a continuous process to run this behavior (not really efficient).

The implementation is simple:

Define a property with a start value e.g. 0

You start the delay by setting a value above zero (e.g. 10 to measure 10 frames).

You observe this property with a property sensor. When the property is above zero you decrement it by 1 at each single frame [True Level Triggering].
When the property reaches zero the time is up and you trigger your event (e.g. by sending a message).

Automatic property

You can use a timer property. The timer property counts the seconds automatically.

You start the delay by setting a value below zero (e.g. -10 to measure 10 seconds).

You observe the timer property with a property sensor.
When the property gets above zero the time is up and you trigger your event (e.g. by sending a message).

Be aware the timer property will continue counting and never stop. You can set any value at any time (e.g. to start another delay).

Delay sensor

This is not so common as there is a small but important obstacle a lot of BGE users stumble across. You need to know how sensors work.

The delay sensor start measuring when the object gets created!

This means it is perfectly fine to measure a time frame since scene start.

It is also fine to add the object and get a delayed event after creation. This way you can establish a sort of timer, just b adding such an object.

But there is more:

The delay sensor also pops when you switch the state of the build-in state machine (from a state without the delay sensor to a state with state sensor).

You start with a state without the delay sensor.
You start measure by switching to a state with delay sensor.

You measure the delay with the delay sensor.


Rotated Gradient Blur in Compositor I have a rendered image (actually sequence of images) and want to 'fake' a depth of field in the compositor by using a blur, or a defocus. My preconceived notion was that I should produce a gradient texture and use either the blur node and a color mix to combine the unblurred and blurred versions according to a factor prescribed by the gradient texture, or use a defocus node with the Z factor prescribed by the gradient. However, this seems much harder than it should be for the following reasons:

Creating a texture for the compositor seems hard - the only way I could find to do it was switching off Cycles and into BI, creating a new texture, and then switching back.
When using a Blend texture in the defocus node, it seems very hard not to get a sharp 'edge' where the blur 'turns on'.
Most confusingly, it seems impossible to rotate a texture in the compositor. In the node editor for a material, this is trivial, but I can't see how to do it here.

Any advice regarding the above confusion, or on a better way to achieve my goal, would be greatly appreciated.

Thanks.

Instead of using a gradient you can build a mask really quickly. Use the shift drag function to extrude a feathered edge from the shape. Invert the color of the mask using the little invert icon in the mask window.


blender 2.8 : how to rotate in 2d view? I'm in Draw mode (gpencil) and set the view to TOP. I want to rotate the canvas like i ussually do on real paper. I want to do 2d rotate the canvas while i'm drawing. Right now, if i rotate the view, it will change to perspective. Does anyone know ?

Below is another way of doing it using drivers.

For canvas to have rotation option, we can use driver for 'y rotation' on an empty object and parent it with Grease-pencil object. This video shows the functionality of it but doesn't show how to do it. There are steps written in description of the video but I found it difficult to follow.

Below are steps to do make the canvas rotate and we not have to move out of the 'draw' mode and the driver would be available by pressing 'N' on keyboard.

Step 1: Create a new file using '2D Animation' workflow from the splash screen of the application.

Step 2: Go to object mode using the mode-change tool at the top-left of the screen. We can also use ctrl+tab to bring the mode-change pie menu and then drag the cursor to desired mode.

Step 3: Press Shift+A and create a new 'empty' object. we used the circle shape because the depicts a actual animation disk.

Also, rotate the circle 90 degrees on x-axis if you used a regular mesh instead of an empty.

Step 4: Press N on the keyboard to open the 'Transform' panel and then right click over the 'y rotation' to add a new driver.

Step 5: After adding the driver to 'Y rotation'. Open the 'Driver Editor' window using right clicking on 'y rotation'. Click on (X) button as shown in the second picture below and choose 'single property'.

Step 6: link the grease pencil object in driver editor under single property.

Step 7: create a custom property for the GP object with following property:
 -  Property Name = Anim Disk
 -  Property value =   0
 -  Min value =    -360
 -  Max value =    360

Step 8: Copy the data path of the created property. Paste the copied 'data path' in driver editor for the 'empty circle'

Step 9: Parent the GP object to the 'empty object'.

Now you can rotate the panel by pressing 'N' on keyboard and then changing the value of 'Anim Disk'


Radeon RX 570 not rendering correctly using Eevee [Linux (Ubuntu), AMD] Recently got my GPU setup, and after a bit of trial and error, I was able to get it to work with everything, until I decided just a bit ago to use EEVEE in blender instead of cycles; I was presented with some serious issues doing it:

I'm running Kubuntu 20.04, OpenGL v:4.5.14756 Core Profile Context 20.40, OpenCL 1.2(2.1?) AMD-APP (3180.7), on a Radeon RX 570 GPU. Drivers are Pro 20.40.
My command when installing the drivers was ./amdgpu-pro-install --pro --opencl=pal,legacy,rocm
I'm not sure how to fix this nor what is even causing it and I'd like to find out how to fix it.

Managed to fix it by manually installing the bundled packages with the term opencl-*_amd64.deb, using dpkg to correctly install their dependencies as needed. This solution from the devtalk may also work and is probably easier, but I didn't try it.


Why is the airbrush grease pencil path so weird? I am trying to add some soft shading by using airbrush, yet the brush path is so weird that there is no transparency in overlapping stroke. Is there something wrong with the setting?
Related tutorial:
(start from 16:17)
https://www.youtube.com/watch?time_continue=1038&v=kX9alavzPzc&feature=emb_logo

In the material tab change the Mode Type from Line to Dots to get stroke edges that blend properly when they overlap


Cant move objects in object mode I have no clue what i have done that i cant move the object now i was just editing stuff in edit mode, i only added a mirror modifier, but that's it. and now i cant move it on object mode - nor connect it to the body -.

I tried most questions and turning on and off most setting that i tought it would block the movement, but i have no clue how to fix this.

i have no clue what more to put here so i can post the question, ill add a blender file with the head obj so anyone can check what it is and hopefully help me find how to enable movement again.

in the 3D View Properties panel (N), all the Transforms are locked


Blender python, what design pattern the Operator class is designed I'm new to Python scripting, and is confused with the design pattern it's used so I do not quite understand how this class works, here is a code example,
class HelloWorldOperator(bpy.types.Operator):
    bl_idname = "wm.hello_world"
    bl_label = "Minimal Operator"

    def execute(self, context):
        print("Hello World")
        return {'FINISHED'}

From the execute() function, how this function is called by Blender and where this 'self' and 'context' comes from remains a mysterious, it has to be somewhere in Blender to call this function.
To sum up a bit, the user defines the real function (the function to be follow a predefined pattern, the function name pattern, the return pattern etc.), then being called by Blender, what design pattern this is?

The HelloWorldOperator derives from the bpy.types.Operator base-class.
The self variable is a Pythonic class pattern, it is similar to this in C++ like languages. The class variables declared in the class header, e.g. bl_idname and bl_lable, are shared across all instances of the class. The self dictionary contains the per-instance variables and is always the first argument in a Python class method. It is automatically supplied on method calls.
The context comes from the Blender environment and contains pointers to the active object, collection, GUI mode and other things.
Classes deriving from bpy.types.Operator are high-level functions designed to be used as GUI callback functions. As such they only return GUI status.


Can I mirror backwards? I want to mirror a building across the Y-axis, but I want the mirrored side to be flipped along the X-axis (I.E. be flipped). Is there a way to do that?

The best way to do this is to make a  linked duplicate of your original object (ALT+D) and then rotate it 180 degrees on the z axis. They will technically be separate objects, unlike  a modifier, but editing one will change the other accordingly.


How can I scale object to fit another object that shares the same shape but are diffrent size. Please teach me how to scale precisely to fit another object.

I am trying to combine two objects that are made based on the same octagon.
I want to make these two object into one connected object. I am scaling looped edge, and am trying to fit that to the other object (see GIF attached). How can I scale it precisely to fit the other object?

If this process succeeds, I can use "remove double",and can combine these two objects.

These are two objects I am trying to combine.

Process I am trying. But I cannot precisely scale to fit the other one.

I got a solution for you, but, depending on object type, it might take longer times to complete as it's not automated.

You take one of the vertices of the outer ring(the inner ones that you want to match up). Than you hold down SHIFT key and select it's corresponding vertex where you want it to be placed(on the inner ring). After than press Alt + M and choose "At Last" option. This way the vertex will be automatically placed at it's desired position and the duplicate vertices will be removed too. Now you can repeat the same process for the rest of the vertex pairs.

I hope this helps! :)


How to keep the original shape when simulating cloth? this is the original shape

after simulation

I want the skirt keep the shape rather than dropping down like this

Maybe it can be solve by Cloth Stiffness Scaling option but I really don'n know how to use it?

Try increasing Bending and Structural. To have an order of magnitude, you can check the Presets :

Silk : Bending 0.05 ; Structural 5.00
Rubber : Bending 25.00 ; Structural 15.00

Stiffness Scaling allows to control the stiffness of specific parts of the mesh. Create two vertex group (one for Struct, one for Bending), assign all your vertices to both groups, them weight-paint them.

Blue vertices will have the stiffness defined in Overall stiffness
Red vertices will have a stiffness of Overall + Max


Clone Stamp affecting opposite side of model? Relatively new to Blender! I have a textured model, and I'm trying to clean up some messy seams. (Long-term I should have placed my UV seams in less visible locations, but at this point, I'd rather use the clone stamp to fix things than repaint my entire model)

When I use the clone stamp, I set the source with the 3D cursor, but when I go to paint, the area I'm trying to paint is not affected, but instead, the opposite side is painted in unpredictable ways:

No clue why this is happening or how to fix it, the only modifier have applied is subsurf, and I can't find any mirroring options that could be affecting the clone tool. Any help is appreciated. (Using blender 2.8)

User Moonboots Had the (rather simple) answer, I had some flipped normals affecting where the clone tool was cloning!


How to create a fire/light effect in a spaceship engine I was wondering how I could create this effect in blender for an animation:

How can I make this bloom effect?

When dealing with these effects, generally you have 2 ways - create some geometry with high amount of lighting and use volumetrics for them or fake these effects with compositor.

Using volumetric materials

You should have some geometry providing actual rays of light; this may be some basic mesh which has forms of rays, or particles emitted from somewhere, forming cloud of light. Then with using volume materials you'll get desired effect.

To begin, either model basic form of rays as mesh as @PGmath suggested or create particles system on the object, which is supposed to emit light, and render those particles as volumetric halos with using Point Density texture which is what I did. See What is Point Density for more info about this feature. See Halo particles don't render in Cycles for details about texture setup (Note: accessible starting from Blender 2.76).

Add a particle system to the object, with vertex groups point it to be emitted from adjacent place (via Vertex Group rollout in particle system's settings). Set up a force field / emission direction for particles to form basic shape of the rays. You might want to disable gravity for particles to stop them falling down while being emitted.
Create several cubes which will contain particles inside. They will serve as domains for volumetric materials. I added particles coming from the floor too, for adding a bit of volumetric lighting across the scene.

Also you may want to position illuminating objects on different layers; this could improve scene allowing to:

overlay objects that illuminate scene while post-processing; this can save render times quite a bit.
control reflections / refractions if needed. See Post-processing Lightsabers in Blender for more info.

In material setup for the domains add Texture > Point Density and Shader > Emission shader which will be connected to Volume output socket of Material Output node. Set Point Density to Particle System mode and choose adjacent one. You may want to add Math node in order to control amount of final effect.

Play animation to let particles emit. After rendering and a bit of post-processing you'll get something like glow where particles are located.

Faking effect in compositor

While you will get nice result with volumetric material it's very heavy for rendering. And since you asked about animation the rendering times may be even more important. Hence it may be worth trying to fake it with post-processing (at least, part of effect). From this point of view, I think How to render lightning in Cycles is related with only exception for actual object.
In case of this scene, I used following steps:

Model the objects, apply emissive material for adjacent parts. Render the image.
In Composite nodes with keying get part of image which is going to be heavily processed. Create a mask which will control where post-processing will occur. Overlay them together.

The Post-processing group is the one used in the first way and it was used for refining the result (adding Glare, Sunbeams, vignette, desaturation of some parts of image and Lens Distortion).

Final result:

The rendering is ~ 15 times less.

There's a lot of room for improving:

if considering caustics in render it may be a bit more complicated to setup;
the result with volumetric materials lacks gradient fade out and consistence of light; result with compositing has too short rays etc.

It may depend on the actual scene requirements / limitations.