How to get index Slot Particle or Delete Slot Particle by Name? After applying Particle Modifier, the Particle slot still exists. As shown above, I want to delete slot "SF_Plane_P_Sphere.002", but slot "SF_Plane_P_Sphere.001" is actived.
And as far as I know to remove it, i need to know its index to be active & remove
bpy.context.object.particle_systems.active_index = 2

bpy.ops.object.particle_system_remove()

but I don't know how to get the index by its name. Or is there a way to delete it by its name ?

You can find the particle system slot index using:
index = bpy.context.object.particle_systems.find("the name you want")


Fluid Simulation problem, some frames render others don't I simulated a fruit drop into a tank (blender guru tutorial) and when preparing to render, some frames of the simulation show up on rendered view while others don't or only partly show up. Why is this?

It's not a camera cut or trimming, since in the same camera position the fluid is visible in one frame and not in the other (not completely)

It's not the visiiblity on render of the fluid sim for the same reason as above

Link to imgur album

That is a bug that I have experienced many times with fluids. It does not affect final render however, so it is not that much of a problem. Just a headache.

Not really an answer I guess, but you can be content to know that you did not cause the problem. You can send in a bug report, but that is really all you can do.


Camera casting weird shadow depending only on it's position As the title already explains I have a shadow in my render without an actual object which casts that shadow. The shadow only shows depending on where my camera is positioned and even when I disable the used lights in my scene.
Picture 1 shows how the object should look with the used lighting.
Picutre 2 shows the exact same object but I rotated the camera around it.
Picture 3 shows how that shadow increases while I rotate further around the object.
Picture 4 shows that there clearly is no other object in the way of the light and that camera itself could not cast the shadow on my object.

I think this should solve your problem: Unless there is some special reason you're using "object", "generated" is usually the best texture coordinate to use for procedural textures. Secondly, if you're using a B&W value as a normal map, it should be run through the height input of a bump node first. See below:


Texture not applying correctly in Blender So, I'm new to Blender and I started to mess around with nodes. And I tried importing a face texture to my head model and it imported it quite weirdly.

Nodes:

Face Texture:

Blender View:

If I understand your requirement correctly you want to map the face image onto one face of your object, and color the rest with a simple color where the image is transparent?
It can be done with simple UV Mapping, and using the Alpha channel to drive the mixing factor.


I'm trying to make a vertex group on one side of a model, but the selection keeps mirroring on the other side too. How do I stop this? The model I'm working on. I'm trying to prevent the selection from mirroring on the other side as well. I plan on having at least independent 5 vertex groups so that I can control the fall of the hair that I'm going to add in. Any suggestions?

The Mirror Modifier is a non-destructive action within Blender. Meaning the changes are virtual and the results do not make any permanent changes.

(This is just a UV sphere with half the vertices deleted and then a Mirror Modifier added.)

When you edit one side of the Mesh a representation of the same change is shown in the mirrored vertices.

If you want the vertices to exist independantly of the Modifier then you must click Apply.

Now the Modifier is applied any changes apply to only the selected vertices.

The same is true of Vertex groups. As the geometry only exists in one place (i.e. the left) when the Modifier is working. As soon as you apply it you can affect any of the now real vertices.


Cycles Volume Scattering totally black I have an issue with volume scattering in cycles. I modeled and textured a model in Blender Render engine and moved it to the Cycles Render engine for render, I ran into a problem with volume scattering. The final render with this option becomes impenetrable dark.

My model in cycles has default material (diffuse bsdf)
For lightning source I use a spot lamp (not sun or hemi)

CPU rendering

Computer specs:

64 bit 8 RAM

Intel(R)_Pentium(R)_CPU_G2030_@_3.00GHz

AMD Radeon R7 200 Series

The density (Volume panel in World) was set to a very high value. Setting it to 0.001 instead of 0.100, will make volume scattering be visible.


(Solved) Will 2.82 files work in 2.79? I have a question, if I model an object and I do the materials, the textures, the animations all that is possible is unimaginable on the version 2.82 of Blender, and that I want to copy / paste on the version 2.79 of Blender because I need an addon to export which is not available on version 2.8, will i have issues/error or something? sorry for my english.

Project files (.blend) created with newer versions of  Blender generally can't be opened by older versions. Blender isn't designed to be forward compatible.


Material doesnt show up in rendered view The material of certain objects in the scene doesnt show up. Also the scene is tainted dark, is this related to the sky texture as background? How do I correct this?

Material view: Mountain and beach texture is there.

Rendered view: Mountain and beach texture is not there. River tho.

Node Setup for the material of both mountain and beach.

World background set as sky texture.

When combining several outputs into some other inputs, you should remember what socket you use and how.

In your case, you don't see any textures in Rendered view because information from Color outputs couldn't be converted properly being plugged into Shader inputs.
And the blue color fullfilling everything in your case is the color of the environment texture (which is added by the Sky Texture node).

Instead you should mix colors, textures, etc using nodes designed for that, i.e. Color > MixRGB one. Its ouput is also of Color type, so you can continue adding some color information to the node tree.

In the very end, when you know you're done with color, plug the final Color output into the Color input of the Diffuse (or another one) shader. After that, you may combine shaders (add some Glossy or Transparent or adding new colors / textures with new Diffuse shaders or  whatever) with Mix Shader node, but there won't be any conversion between Color and Shader type.

You may want to look at meaning of the color of the nodes sockets for more info on different sockets' types.


How to remove a linked library in blender? I'm following a tutorial in which I built a building by linking objects (walls, floor, windows, etc.) from other files, making a proxy of the linked object, and then using linked duplicates of the proxy to build the structure.

In the most recent part of the tutorial, we were supposed to make copies of the asset files (of the building parts) so that we could rename the mesh data. Then I linked the objects from the new asset files, made a proxy of that object and then linked the object data from that proxy to all the duplicates of the old asset.

After that, I should be able to delete the .blend files for the old assets. However, it turns out there are still some users of these libraries:

When I looked around the data-blocks, I found there were objects that used the data:

The problem is, these objects don't actually exist anywhere in the scene.

Now, I think the error I made was that I deleted the original proxies without overwriting their object data. However, at this point I've already done so much work that it'd be a drag to go back and do it over again.

I know I could just leave everything as is, but I'd really like to clean up the data blocks and delete the old .blend files. How can I get rid of the datablock for the deleted objects? Or else is there a way to unlink the library?

Thanks for your help!

(I would include the .blend file, but I figure it's not very useful without the accompanying asset files, I'm not sure how to upload all those things together. If that seems important for solving the problem, then I can probably just put a .zip in my dropbox).

Okay, I figured it out!

In the outliner, I went to "Blender File" and beneath the "Current File" data, all the library files were listed. From there I could simply right-click and delete the unused library files.


snap / selection the deformation bones of my bird to the cursor does not work as expected I'm following the piero training course video tutorial and I reached the rigging stage (for who has already completed the tutorial,I'm on the  "23_piero_rigging_wing-part_1" on minute 31:00).

I'm trying to rig the wing of the bird. This is what happens to me when I do "snap / selection" the deformation bones of my bird to the cursor :

what happens to my bird

instead,this is what should happen (you will see only a little part of the full video) :

this is what should happens

Can someone tell me why ?

This seems to be an unexpected behavior.

If you select the bones in pose mode, then switch to edit mode :

If you select the bones in edit mode :


Blender can't see through glass because reflections are too hard I have this mesh

When I add glass on top of it I can't see through it when I'm at an angle.

The glass material is an extremely basic one.
How can I make it that the glass acts more naturally?(more see through less reflection)

I was able to fix it by giving the glass thickness with the solidify modifier.


Saving user preferences per project I thought it had been asked already, but I searched, couldn't find anything for Version 2.74.

Is there a way to save user preferences, like hotkeys or enabled addons, into my .blend file? I may need specific keyboard shortcuts for a certain project, so I want to save the preferences so they would load ONLY for this project when I open it, and when I press Ctrl+N - it would load the default startup settings.

One way to do that is by manipulating with startup.blend's.

(I feel Python solution probably should be somewhere here... Also this way is a little bit strange because of dealing with multiple config files)

I save user settings so the main startup.blend (default one) looks
like this:

In this .blend which will be the startup for the main
project, continue setting up new preferences. Change Grid color in 3D View so it differs from default settings, activate some addons etc. I also dropped default lamp and made deselecting everything to happen on Ctrl + Shift + Alt + A, so the startup-for-CurrentProject.blend looks like this:

Create backup of the main startup.blend (renaming it to
startup_Main.blend), save User Preferences in the opened .blend.
Open file browser, find there new generated startup.blend (how to find Blender's config file), cut it
from there and paste in work folder. Also rename this one in
something user-friendly, like startup-for-CurrentProject.blend
(for ease). Now, you'll be opening CurrentProject.blend using this
file. Also, make sure to rename the main startup_Main.blend back
to startup.blend so Blender to find exactly this one, not
something else.
Without closing Blender continue creating something or open .blend which will be the main project, I call it CurrentProject.blend. I added something so
it to differ from that bunch of startups. Saved it.

Now if creating / opening blend (or reloading default one by Ctrl + N), you'l see that default user preferences remained unchanged.
To work on your project now you should open work folder and that
    startup-for-CurrentProject.blend you've saved earlier. Press
    Ctrl + O to open saved project using these
    settings. Find CurrentProject.blend and load it.

New settings were saved including enabled addons and keyboard
shorcuts.

Now, you have two .blends in work folder -
startup-for-CurrentProject.blend and CurrentProject.blend.


Volume materials rendering weirdly I have a bunch of cylinders with a possibility of having 1 of 7 materials. The only difference between them is the transmission color however they render differently. What's causing some of them to be black?

Here's the blend file: https://www.dropbox.com/s/u1p9l6dq31d33kh/weirdVolumeMaterial.blend?dl=0

You have a few instances of overlapping faces, and some cylinders directly above other cylinders with faces touching or overlapping.

You also have a few instances of objects inside objects.

Depending on your volume material settings that can lead to artifacts, and in general Blender doesn't like it, confusing the rendering engine on how to calculate depth and render the volume materials.

Overall your scene might benefit from some optimization. Since all cylinders seem to be roughly the same shape you don't need so many unique mesh data. You could probably make them all instances of the same object and simply scale them differently in the Z axis.

This will make your workflow easir if you ever need to edit the shape of the cylinders, and also make your scene lighter and faster to render since there's less unique geometry to upload into memory.

Also make sure you apply materials by object (as opposed to by data) right next to the material name dropdown menu, so each instance can have it's own material definitions


Mirror Modifier Weights Not Working I got something rigged with the .L side of the armature and tried applying a mirror modifier in hopes that the weights would mirror and be controlled by the .R side. I've done this before in this project and it worked fine.
This time, however, I got this:

After some digging, I found out the following:

The selected bone has no control of the mesh whatsoever. The mesh doesn't even have any weights assigned for it.
The part of the mesh that is messed up has weights assigned to other bones that it doesn't need
Trying to add the weights manually doesn't make things better. In fact, it makes it get further away from the bone.
The bones are symmetrical and have the correct names and endings (.L and .R)

I can't seem to find any hint of this problem anywhere. Does anyone know what's going on and how I can fix it?

After a bit of digging when I ran into this issue again, I found out that for whatever reason, the vertex group for that particular bone didn't transfer to the mirrored mesh. As a result, the weights for the mirrored object were there, but the wrong bone was controlling it. In my case, I mirrored to the right side, and that part of the mesh was being controlled by the left side. Here's the solution I found:

Figure out what the missing vertex group(s) are in the vertex group panel. Watch for the one(s) that doesn't have a counterpart for the other side (For example: if there's a hair1.L and no hair.R, you've found one). Select the one for the side that you do have.
Use the grey arrow below the plus and minus buttons to copy the vertex group within the object and lock the original version.
Rename the copy to the bone you want to control it with (For example: hair.L_copy would be renamed to hair.R).
While the bones have control over their intended weights, they will still control the wrong side. Go ahead and fix this in weight paint mode by subtracting from anything that they don't need. Don't forget to unlock any vertex groups that you locked before.


Cannot render, because of too many faces i'm having a rookie issue. I'm trying to make a train station, which would include a train. Problem is that i can't render anything without blender crashing. This is: Blender 2.8 Eevee or Cycles (here is were i originally made the models). I also tried transfering the train in the picture to 2.79 (this changed nothing). Notice everything is set to render in 1280x720 px and with 150 samples.
I tried rendering with the subsivision modifier "on" and "off". Blender crashes every time.
On the bottom righ of the pictures below you'll see my faces count, i'm guessing its ridiculously high, but i need the detail to achieve i a photorealistic effect (hopefully).
I simply mean to get still images, nothing more. Anyone knows a possible solution?

Edit 1: I neglected to provide my laptop's specs, is not tthat grate but shouldn't be a problem (read edit 2):

Operating System
    Windows 10 Home 64-bit
CPU
    Intel Core i7 @ 2.70GHz 42 °C
    Kaby Lake-U/Y 14nm Technology
RAM
    8,00GB Single-Channel Unknown @ 1063MHz
Graphics

Intel HD Graphics 620 (HP)
4095MB NVIDIA GeForce 940MX (HP)

Storage
    931GB Western Digital WDC WD10JPVX-60JC3T0 (SATA)   30 °C
    119GB SanDisk SD8SNAT-128G-1006 (SSD)

Edit 2: I've done more before
I figure i'd check an old render i did on on blender 2.79, on this very same specs. I was able to render with no issues and the faces count was of almost 12 millions. Now i tried rendering the first picture (1.5 million faces), following the instructions left by one of the guys (lower sub-divs levels and use cycles). Still crashed. Could it be a Blender 2.8 BETA thing?

Lower your subdivision modifier from 6 to 3 (at most: 3).
Please check double geometry on all of your models (even simpler ones) There could be intersecting double faces. Enter edit mode, press F3 (to search) or Spacebar (user preferences to set spacebar to search) and while in edit mode, type "remove doubles".  You´ll get notification on how many edges were cleaned.
Also check your materials don't contain special characters, this is another reason why in the process of "pre-processing" before rendering the render crashes. Make sure spaces are appropiate (use a "." or "_" to separate numbered versions of the materials or the meshes)
6 millions of polygons shouldn´t be a big deal if you have 12GB+ of Ram. Also switch to CPU rendering only. Do not process with EEVEE. Use Cycles. /// I´ve render 15 million polys on Cycles on CPU due to the lack of processing on 12GB VRam for GPU on my Titan X card. So you may as well play safe on the Cycles CPU render part thus answering this question.

Thank you for your consideration to vote me as the answer by clicking to the left :the icon with a check mark and upvote this answer.

BFCT_Schiller


How do I reset my keyboard Shortcuts? By accident I added left mouse click as a shortcut for toggling fullscreen for the active window. That won't allow me to get back into user preferences to rechange it. Is there any other way to change keyboard shortcuts?

This shouldn't affect anything if you're clicking directly on buttons but you can use CtrlAltU to bring up your user preferences or press Space and search for it there. Next go to the Input tab and look for a button next to Window marked Restore (Blender remembers what changes you make and offers a handy way to reset only that section without messing up any other keybindings you remapped). From there you can use to set it back to the default value of whatever config preset you are using.

If you have nothing to lose you can also bring up the space menu and type load factory settings then save that as your new startup settings.


Export File Dialog in Blender 2.80 How can I get bring up a popup file browser in Blender 2.80 invoked by a button click in my addon, to define the name and location of a file to be exported?

In Blender 2.7x, I did this via the context window manager in the invoke function, but it is very possible that this hasn't been the preferred method for years, as I'm not finding useful documentation when I search for how to update this.

class MYTOOL_OT_write_data(bpy.types.Operator):
    bl_idname = "mytool.write_data"
    bl_label = "Write data file"

    directory: bpy.props.StringProperty(subtype="FILE_PATH")
    filename: bpy.props.StringProperty(subtype="FILE_NAME")

    def invoke(self, context, event):  # 2.7x method
        WindowManager = context.window_manager
        context.window_manager.FILEBROWSERect_add(self)  # <-- error here
        return{"RUNNING_MODAL"}

    def execute(self, context):
        directory = self.directory
        filename = self.filename
        # Write csv data file using normal python functionality
        return{'FINISHED'}

In Blender 2.80, I am getting the error "AttributeError: 'WindowManager' object has no attribute 'FILEBROWSERect_add'".

Thanks for your help.

UPDATED SOLUTION based on brockmann's solution below.  The trick is to use the ExportHelper util (which existed long before Blender 2.80):

from bpy_extras.io_utils import ExportHelper

class MYTOOL_OT_write_data(bpy.types.Operator, ExportHelper):
    bl_idname = "mytool.write_data"
    bl_label = "Write data file"

    filename_ext = ".csv"  # ExportHelper mixin class uses this
    def execute(self, context):
        filepath = self.filepath
        # f = open(filepath, 'w')
        # f.write(stuff)
        # f.close()
        return{'FINISHED'}

Have a look into the Templates: Templates > Python > Operator File Export. For convenience the script adds some predefined properties as well as a custom entry to the File > Export menu:

import bpy

def write_some_data(context, filepath, use_some_setting):
    print("running write_some_data...")
    f = open(filepath, 'w', encoding='utf-8')
    f.write("Hello World %s" % use_some_setting)
    f.close()

    return {'FINISHED'}

# ExportHelper is a helper class, defines filename and
# invoke() function which calls the file selector.
from bpy_extras.io_utils import ExportHelper
from bpy.props import StringProperty, BoolProperty, EnumProperty
from bpy.types import Operator

class ExportSomeData(Operator, ExportHelper):
    """This appears in the tooltip of the operator and in the generated docs"""
    bl_idname = "export_test.some_data"  # important since its how bpy.ops.import_test.some_data is constructed
    bl_label = "Export Some Data"

    # ExportHelper mixin class uses this
    filename_ext = ".txt"

    filter_glob: StringProperty(
        default="*.txt",
        options={'HIDDEN'},
        maxlen=255,  # Max internal buffer length, longer would be clamped.
    )

    # List of operator properties, the attributes will be assigned
    # to the class instance from the operator settings before calling.
    use_setting: BoolProperty(
        name="Example Boolean",
        description="Example Tooltip",
        default=True,
    )

    type: EnumProperty(
        name="Example Enum",
        description="Choose between two items",
        items=(
            ('OPT_A', "First Option", "Description one"),
            ('OPT_B', "Second Option", "Description two"),
        ),
        default='OPT_A',
    )

    def execute(self, context):
        return write_some_data(context, self.filepath, self.use_setting)

# Only needed if you want to add into a dynamic menu
def menu_func_export(self, context):
    self.layout.operator(ExportSomeData.bl_idname, text="Text Export Operator")

def register():
    bpy.utils.register_class(ExportSomeData)
    bpy.types.TOPBAR_MT_file_export.append(menu_func_export)

def unregister():
    bpy.utils.unregister_class(ExportSomeData)
    bpy.types.TOPBAR_MT_file_export.remove(menu_func_export)

if __name__ == "__main__":
    register()

    # test call
    bpy.ops.export_test.some_data('INVOKE_DEFAULT')


Beginner Guide for Efficient Modeling I'm fairly new to Blender and 3-D modeling in general.  I created my first model and was pretty proud of it.  However, when I finally thought about it and noticed it, I decided 400,000 faces may have been a few too many.  So to my question:

Does anyone have a basic set of rules and/or a guide they follow as they model that will help lead to proper technique and efficiently rendered models? Triangles vs Quads, when to (and not to) subdivide/subsurf, is there anything wrong with making a high-res version and decimating/shrinkwrapping after it's done?

Like I said, I'm a beginner so I want to make sure I'm doing things correctly and won't be forming a bunch of bad habits I will have to correct later.  So a step by step workflow, or tips on things to avoid, etc.  I've been doing a lot of research, but haven't found this type of information broken down well.  I don't necessarily need a large amount of detail - just a basic list to act as a guide of more things to research as I model.

(It is worth mentioning that most of my models will be used in a realtime application, so I am aware I have to get my polycount WAY down)

Your question is a duplicate of:

Best practices for learning Blender

You might also check:

https://www.google.com/search?client=ubuntu&channel=fs&q=blender+best+practices&ie=utf-8&oe=utf-8
https://en.wikibooks.org/wiki/Blender_3D:_Noob_to_Pro/Avoiding_Headaches_Early_On:_Good_3D_Modeling_Practices


Convert Blender Render materials to Cycles I am doing the Introduction to Camera Tracking in Blender tutorial by Blender Guru. Starting at 47:20, he does things with materials and textures in Blender Render that I don't understand (I have decided to focus my learning on the Cycles Render Engine). It ends at about 51:00. How do I create these materials in Cycles?

Here is the .blend file:

Got it! Here is my result from camera view showing only the hole:

The first thing I did was flip all normals by keying Tab to enter Edit Mode, T to toggle open/close the Toolshelf, going to Toolshelf > Shading/UVs tab > Shading dropdown and clicking Flip Normals. This ensures that the textures display properly on the inside of the tube.

Second and lastly, I modified your node setup to this:

For the Image Textures, red_rock is still on top and brown_dirty on the bottom. I did not change how the color is integrated, but they now have bump mapping for each that is averaged by a Converter > Vector Math node. The additional Separate XYZ and other top nodes add the Ambient Occlusion shadows. Separate XYZ makes the darkness align to the local Z-Axis. The Gradient Texture mostly serves to convert the z vector to a Fac: value for the ColorRamp, which decides how much black and color there is. The MixRGB's bottom color input actually decides what color appears in the tube.

Here is the .blend file:


Set image settings for each individual File Output Node, in the Python API In one scene I have two seperate FileOutputNodes and I want different color depths and file formats for each.
In the Blender GUI this is simple. You can press a FileOutputNode, then press N. Then the Properties panel shows and you can change the image settings for each node.
How do I do the same through the python API? I tried creating seperate bpy.types.ImageFormatSettings for each node, but unfortunately that attribute is read-only.

In particular, I want one node to have Open_EXR, 16-bit RGB; the other PNG 8-bit RGB.
I know I can create two seperate scenes and set the image settings for each scene, but I'd rather have one scene (because that's less code).

You can actually set the settings for each individual node.
Create your node:
file_output_node = tree.nodes.new('CompositorNodeOutputFile')

Then you can set your settings for this node by going into the format attribute. For example:
file_output_node.format.file_format = "PNG" # default is "PNG"
file_output_node.format.color_mode = "RGB"  # default is "BW"
file_output_node.format.color_depth = "16"  # default is 8
file_output_node.format.compression = 0     # default is 15


How to fix rotations on bones? so I've created this Character and was trying to give him some bones. I add the IK bone to move the legs around. For some reason as soon as it gets to a certain, point the bone starts to rotate giving weird deformations in the Hip. Another thing is that the feet are deformated all the time when I'm in pose or edit mode, I don't know why. How can I remove these deformations?

You need to correct the bone's Pole Angle (choose -90°). Also, you'll need to move the Pole Target bone so that your leg doesn't twist too much when moving.


Blender 2.80 Multiple Quick Selections in Outliner In Blender 2.8 Outliner, what is the best way to quickly select many items that are in a row and without individually clicking on each item? Shift+Left Mouse Click or CTRL-Shift+Left Mouse Click does not work.

Like in the below image, want to select quickly all items between the first and last selected.

I thought I update my post so the latest selection feature is in here as well.

Now blender allows the windows type of selection by clicking on the first item to be selected in the outline and scrolling to the last item of the selection sequence and holding Shift down and Left Click on the last item. All the object will be selected between the first and last selected items this way.

Original answer below which was the only valid way of selecting multiple items at the time of original posting but it is still a valid selection process as well:
The fastest way I found is pressing B on the keyboard for Box Select and select and drag a box, with the left mouse button, around the required items. You can add more to the selection by scrolling, if you have more to add that is not visible on the screen, and pressing B and selecting more items again.
It still can take a while if you have a 100 or so items to select but currently the fastest, unless someone knows another better way.
This may change, as 2.80 is still in beta, but currently that is how you can select consecutive objects faster in the Outliner.


OSL: Can I use a closure as an input to an OSL script? I'm experimenting with NPR materials in Cycles, in particular, half-toning and hatching. In order to make things work, I often have to bake the output of a Cycles shader to a texture map and, in a second session/pass, multiply the colors in that map with a halftone screen, put the result through a threshold, etc., and feed the result back into say, an emission shader, to render the result.

Would it be possible to write an OSL shader that would accept a closure color as input (like the Cycles 'Mix Shader' node) so I can use the output of, say, a Diffuse BSDF node as the input for further calculations? (so as not have to bake it first?) I've seen OSL scripts which contain the grammar for this, but I've never seen it used.

At least, for example, it would be nice to be able to combine the outputs of Cycles closures in other ways than the factored mix provided by the 'Mix Shader' node. Maybe multiply, subtract, and all those other modes.

Being an OSL baby, I'm afraid I might be getting the shading logic all wrong- I don't understand why I haven't seen this done in any of the OSL scripts I've seen - even if it worked, would it be an abuse of the rendering system?

When OSL is enabled in Blender all shaders are compiled using OSL.
Therefore the Add Shader and Mix Shader are very good examples of what you are looking for.

The next script is the implementation of the Mix Shader node used in Blender 1.

shader node_mix_closure(
    float Fac = 0.5,
    closure color Closure1 = 0,
    closure color Closure2 = 0,
    output closure color Closure = 0)
{
    float t = clamp(Fac, 0.0, 1.0);
    Closure = (1.0 - t) * Closure1 + t * Closure2;
}

BTW I don't see it as abuse of the render system but still be aware that OSL will not allow you to do many operations on a closure

  At present, the only type of closure supported by Open Shading
  Language is the closure color, and the only allowed operations are
  those that let you form a linear combination of closure color’s.
  Additional closure types and operations are reserved for future use.

- closure color:  unary negation
color * closure color: component-wise scaling
closure color * color: component-wise scaling
float * closure color: scaling
closure color * float: scaling
closure color + closure color: component-wise addition

Other operations are not supported. and that said there is just a little room left of things to do, what cannot be done by a set of Add Shader and Mix Shader


Unwrap Curved Flat Stripe How to unwrap this curved flat surface?

How to unwrap such mesh properly? I want to fix texture mapping on the curved part of the mesh. My plan is to make smth like river animation(U coordinate animation).

Wireframe and texture:

Thank you!

start with a shape like this and unwrap it.

then add an array modifier and a curve modifier to control the array.

Blend file here


Change the background clip after tracking - multiple clips loaded I did some motion tracking on a clip and set the clip to be the background of the render. However I then loaded another clip to use instead, did the motion tracking, clicked 'Set as Background' and looking from the camera perspective in the 3D view I see this new clip as the background. However upon rendering, the background appears to be the old clip. How can I remove this old clip so I can see the new one instead?

Thanks!

Whatever you have as background image on the 3D view is just for viewing and work on the scene, but never gets rendered.

The background for rendering is set on diferent places depending on how you are rendering.

On the node editor:

If you're not using nodes:


Shape keys: Reset part of the model or only use specific faces possible? I am currently trying to apply shape keys to a high poly model, which has got a mirror edge, but that modifier has been applied to properly apply textures on its surface.  Somehow, due to little differences on the x-axis, I got a kind of unexpected result as I copied a shape key from a topologicial mirrored shape key.  In this, I only want parts of the horse's mouth to change so that it can take the bit of its bridle properly. I don't need the rest of the unwanted changes. Is there any way I can reset or unshow those parts of the shape key results that I don't want (don't affect all the object's faces by the shape key)? If there is anyone out there having figured out a solution, who might tell me, I'd be very happy for the help.
Pictures for explaination below.
 (Basic mesh)

Enter edit mode through the broken shape key, select vertecies that you do not want to affect your basic mesh and then press 'space' and search "Blend from shape" press 'enter
Then press T and on the left you should see options down at the bottom
1-select basis (your basic shape key)
2- Blend 1
3 Turn off Add


GPU Compute (CUDA) Frequently Crashes Computer I've run into a rather irritating issue when dealing with a somewhat computationally complicated scene (attached below) that is essentially just a pile of volumetrics and lighting.

Whenever I set my project to GPU Compute mode (and set the tile settings to optimal for that), I run the risk of crashing my computer the moment I hit Render. I've Googled around for this issue, only retrieving responses for "Display Driver has stopped responding" messages and black image outputs during rendering. In my case, my displays just turn off after displaying "No Signal". It does not happen EVERY time, though, and I'm having trouble pinning down the trigger.

I've given it 5 minutes of black screen in hopes that it would come back after the scene finishes rendering (in the attached, the current settings usually wrap up after about 2 minutes on my GPU). I have also checked every optimization setting I could find in the project in hopes of alleviating this to no avail.

This has not happened yet in a simple scene. I am exceedingly new to Blender so I can only assume that I've done something terrible to my setup here. However, I would also not be averse to any sort of GPU version of Memtest that I have not tried, in case it's something hardware-related.

CPU Compute mode is not really an option for me, my aging i7 takes almost 30 hours to complete rendering at 1920x1080 (16x16 tiles, path tracing, 7 threads so I can still use the computer, 576 samples after hitting "Square Samples").

Specs:
 - Blender Version: 2.77a
 - OS: Windows 7 Ultimate x64
 - CPU: Intel i7-2600 @ 3.4Ghz
 - GPU: NVidia GeForce GTX 780 (3GB)
 - RAM: 16GB DDR3 1600

Project Files: https://dl.dropboxusercontent.com/u/39096583/Blender.zip

P.S. Thank goodness for RAID1: every time this issue happens, I get notified that the array needs to be verified and repaired. Feeling good about my choice to go with that over RAID0 or a JBOD...

It's common for this problem to be caused by running out of VRAM on your card.

One way to alleviate the problem is to reduce the tile size. Some of the things in a Blender scene can be swapped to and from the GPU on a per-tile basis. In those cases, a smaller tile size means less data on the GPU.

Other things will be the same size on the GPU regardless of which tile is being rendered, or how big the tile is. Hopefully, that overhead is small enough that reducing the tile size will help.

Cetagon's suggestions are also worth checking out.


Appending Materials Automatically I am relatively new to Blender. I come from Sketchup for modeling and Simlab Composer for rendering. In Composer there is a function to save the material palette. Then if I have a model that uses similar materials I can re-apply all of the materials in one click using the saved material file. My question is does Blender have a similar function? I figured out how to append materials, but then I have to go through and apply them. For example any material that uses nodes does not append with the nodes intact. So I have to append the node tree and then redo the material with the correct nodes. This is very tedious and time consuming. Maybe I'm doing something wrong? Thanks in advance.

I don't know if this is what you need. But in Object mode select the objects without the materials, select the object with the material and press CTRL+L then click materials. now the objects will have the same materials.


How would I create a circular brick platform? i'm new to blender, and wanted to make some assets for ue4. I want to make a platform like this .  I've tried a lot of different things, and only one has worked somewhat so far.  Here's my result .  I can't seem to get the same result as he did.  How would you suggest to get similar results, look wise and detail wise.(Each of his bricks looks different and unique, i.e scratches and size, where with my result I just made a circle extruded it and added faces) Any help would be appreciated.
Thanks!

You can use array modifiers.
1st create a nice brick.

Then add an array modifier with a relative offset of 1 on X axis. Change the count to see the effect (I used 5), but it won't be used later.

Add another array modifier with a relative offset of 1 in Y axis. The count will be used and can be adjusted as you like.

Add a curve circle. It has to be a curve, not a mesh.

Select your brick and add a curve modifier, set the "object" as your curve circle.

You can see the shape changing to semi-circular.
Now in the 1st array modifier, change the fit type to "fit curve"

This will adjust the number of bricks to fit the curve's length. Scale smoothly your brick to adjust.


Blender for Engineering: Numbering and naming objects in blender I am working on technical drawings with Blender using MeasureIt. I am following  for making blueprints of specifical parts this youtube tutorial, and it works great.
 But when I am producing "big picture" drawings where I want to show the numbering and naming of different parts -which I'll produce blueprints of-  of e.g. a motor, I have to do it in PowerPoint. But this I think is a bit shabby. I wonder if there's a way of doing it in Blender?

I'm thinkink about something in this fashion, with a legend:

That's what grease pencils are inicially for. However, I don't think there is any way to type in text although there are some addons (I never tried  this myself) and discussions.


Close A Wallsystem in archpack I have a simple question about the archipack addon.

I want to create a complex floor with several rooms etc. now I'm trying do draw the surrounding walls, but how can I close the wall system of the surrounding walls?

Only when the walls are finished with a right click will the checkbox to close under the properties window show up.


Is there a way to make comments in the node editor? I'd like to have a node like the Frame node but one that can have lots of text, not just a header. I've looked and it looks like there isn't any such capability so far, so I was wondering how easy it would be for someone to create a custom Comment node as an add-on or script (I don't know the differences between the two). I myself would love to leave detailed comments in complex node trees so that I can figure out what I was doing/what to do when I come back to them months later.

Since version 2.74, blender has has the ability to display text blocks in the node editor.See the manual.

Add a frame node, then in the properties region add the text block you want to display. (A text block is simply a file made in blender's text editor.)

The frame will display the text exactly as it is in the text editor without word wrapping, you have to add the line brakes in manually (by pressing Enter at the end of the line).
This is the easiest way to make notations in the node editor.


How to make a material switching from Wire frame material to surface material? Is it possible animating the wire frame material Changes to surface material?

I want to make a material that's first Wire & it fades to solid surface material & Vice versa.
Blender Internal Engine

I don't know if there is a better way (I don't usually use Blender Internal) but this can be done with material nodes to generate the wireframe using the UV coordinates.

To generate the wireframe we can use the default unwrap (or use UV Unwrap->Reset to reset back to default) and have the material solid if U or V is less than 0.1 or greater than 0.9 (use values closer to 0.0/1.0 for thinner lines).

To get the wireframe to slide across the mesh we can split the coordinates into the respective components and use Math nodes to generate a cutoff, keyframing the value to animate the transition. Note that I've used the X coordinate (split from the vector using the Separate RGB node (RGB translates to XYZ), combined with a fraction of Z so as to make the transition plane not coincide with the sides of the cube (or you get an ugly transition as the whole face jumps between being transparent and not transparent).

Ensure to enable Transparency in the Render Pipeline Options of the material to allow transparent materials.

This produces the following result :


Appending a Grease Pencil rig breaks it I have a simple 2D Rig created with Grease Pencil and deformed by weights/lattices, this is what it looks like:

But when I try to append it to another scene it looks like this:

I'm not sure why this is happening, the only way I have found to take it to another file is by importing the scene instead of the collection, this doesn't solve my problem though as the rig is in another scene
My guess is that it has to do something with strokes that are scene dependent and for some reason aren't dragged in along the rest of the rig while appending.
Does anyone have a clue why this happens?

The rig you uploaded has been drawn on frame 3, while if you append it on a new scene it's set on frame one. Even if you go to frame 1 in the rig file some strokes disappear.
To solve, you can open a grease pencil dope sheet editor and grab all strokes to frame one, or simply start animating from frame 3 and above.


How not to lose quality of image with brush I'm using texture material on the brush and the quality is way worse than I would like.Original

Painted with a brush

When creating your texture that you are going to paint to, increase this number. (smaller is lower resolution, larger will allow for more detail) It is a good idea to keep powers of 2, such as 1024, 2048, 4096, 8192 Etc.

In your case, when you already have an image made, you can adjust the size of your image in the tools panel of the UV/Image Editor


Is there a way to use meshes as basis for a group of smaller meshes? Is there a way to do what I mentioned in the title? For example if I have a bunch of smaller highly detailed boxes that act as bricks and one low detailed box acting as a house, is there any way to make it that this said house is replaced by an array of these bricks? I am planning to use this high poly model as a basis for textures and normal mapping for a low poly model in Unity.

This is just an aid to modeling, not a fully-automated 'fill my wall with bricks' system.
This example - X across, Y up, Z out

Make a template

My bricks are 2x1x1, so this starts with an composite offset array of 2x1 plane primitives.

Array 1: Relative Offset of 1 in X,
Array 2: Relative Offset of 1 in Y, 1/(2*Array 1 Count) in X,
Array 3: Relative Offset of 1 in Y.

(I put the X-offset in Array 2 into an expression driver, to automate it when I changed the width of the wall.)

Result:

Make a group of your bricks, correctly oriented

CtrlG Group the variants of your bricks.

Note their orientation - in the result all the duplicates will face out in the object's positive Y, across in Z, and up in X. This means that if you rotate their meshes in edit mode, that counts as more variants.

The origins of the brick objects will lie on the template.

Emit the group of bricks as a particle system from the template

I've illustrated all the settings that matter. Things to note:

The only settings are the ones shown, everything else is switched off. (No physics, etc.)
All the particles are emitted on frame 1.
The number of particles is (count array1) x count (array2) x (count array 3).
Use Modifier Stack is checked.
You can change the Render > Size setting to put some mortar between the bricks, if you render the emitter, too.

You can make copies, change the array dimensions, and fit corners....

At any stage, you can hit 'Convert' in the modifier put into the template's stack by the particle system to make all the bricks real instances. Identical bricks still share Mesh Data. If you want to edit individual bricks, go into the brick's Data tab, and click the 'number of users' section of its title bar to make the mesh data single user, so your edits don't affect multiple instances. To do that to multiple bricks at a time, hit U > 'Object and Data'

In this .blend, the driver panel is open, to show the way Array 2 is set. If you change the dimensions of the array, you will have to go in and change the number of particles to suit, though.. that can't be driven.


How to create smooth surface (skin) for a model made of beams? I need some help here.

I am interested in a model here:
https://www.cgtrader.com/3d-models/character/woman/ballerina-dancer-abstract-sculpture-6

This model is made of connected cubes and beams, but I need to use the model with smooth skin. May I ask what is the best approach to create smooth skin for this model?

Many thanks!!!

I think your best way forward is to either contact the producer of that model (they may have a version with smooth skin rather than the cubes and beams) or to reproduce a similar model and pose using a model created with a tool such as MakeHuman  or the Manuel Bastioni Lab add-on (although that looks to have been discontinued... however, there's a community supported branch available at https://github.com/animate1978/MB-Lab/wiki).


How to delete an existing menu? I want to replace an existing menu with an add-on.
You can add your own menu with "append" or "prepend", but you want to delete your existing menu and add your own menu.

If you simply empty an existing class as shown below, you can delete the existing menu, but it will continue to output errors to the console.

Delete the top bar menu

bpy.types.TOPBAR_HT_upper_bar.draw = None

bpy.types.TOPBAR_HT_upper_bar.draw expects a draw function. Here is an example for how to replace the built-in draw function with your own:

import bpy

def draw_function(self):
    self.layout.label(text="New Custom Menu")

bpy.types.TOPBAR_HT_upper_bar.draw = draw_function


Particle System interact with objects I'm currently working on a carved wooden heart lying in a field of grass using the grass essentials you can grab from Blender Guru and as you can see there is some clipping that occurs. I know how to make sure grass wont appear from under the wooden heart, that is not the issue. What I want to do is make it so that the grass around the edge of the heart is slightly bent, that you can actively see the grass is being pushed aside by the object. Is there a way to do this in the particle system? The only thing I can think of short term is to apply the particle system and just do it manually, but with so many vertices that would be an absolute pain to do.

Any help would be greatly appreciated.

The Particle Edit Mode could be quiet handy for this. The settings can be found in the left menu (shortcut T). Also there is the option to just edit the tips (see bottom toolbar).
For "real" interaction you probably need to use Hair dynamics and add a Collision component to the heart


Change object.color property of multiple objects at a time without scripting? Is it possible to change the object.color property of multiple objects at the same time without scripting?
For a lot of stuff in the properties tab, even modifiers, you can hold down ALT while toggling a certain property and all selected objects will be affected, but I can't find a way to do it for the object.color property:

I'm aware you can also use materials and just link materials, but the question is about object.color.

The ALT multiple-property editing mechanic does not work if you click directly the Color Wheel, however it does work if you're tweaking the Red, Green or Blue channels of the color.
Note that you will have to set the display to RGB instead of the default HSV beforehand. It does not matter if you press ALT when clicking on the color field, but you do have to press it when scrubbing or before inputting a value in one of the channels.
Illustration :

Also note that if you are scrubbing a channel field, the value of that channel in all the selected objects will get relatively incremented by the scrubbed value, but if they start with a different color, their color won't always match when you finish scrubbing.
Illustration :


Switch to camera from linked group I have a .blend file with my game character, including camera. Character elements are in the same group. I'm linking this group into the second file. Unfortunately I cannot switch to the linked camera properly. Is it possible to switch to camera from linked group?

Ok, I found a quite nice workaround. One can just add a Scene->Set Camera actuator to one of the objects in linked group (for now I'm adding it to my character object) and feed it with camera. If the game engine will be enabled with this group linked to the scene, linked camera will be picked. One drawback I've noticed so far is that the rendered viewport is not limited respectively to the camera boundary if you use this method.

EDIT:
Actually, if you enable game engine in camera view (it can be any camera) the viewport is limited as usual.


Save a file with filename prompt from script? I'm trying to write a simple script to save without Blender showing the confirmation popup. This works fine if the file already has a name, however, if I call bpy.ops.wm.save_mainfile() and the file has not been previously saved, Blender simply crashes/exits completely.

So is there a way to call save_mainfile() so that it behaves the same at the normal File/Save operation where it will prompt the user for a filename? (Note that calling save_as_mainfile() also crashes Blender.

Here's what I was at least hoping would work:

def execute( self, context ):
    if not bpy.data.filepath:
        bpy.ops.wm.save_mainfile( ?parameter to prompt for filename? )
    else:
        bpy.ops.wm.save_mainfile()
    self.report( { 'INFO' }, 'File saved.')
    return { 'FINISHED' }

After a bit of research, I found a solution for you.

To fix your issue, simply pass the value 'INVOKE_AREA' into save_mainfile, bpy.ops.wm.save_mainfile('INVOKE_AREA'). This will open a file selector if the file is not saved, otherwise it will bring up a prompt that confirms the user wishes to save over the file. If you want to avoid the confirm dialog, you will need to call save_mainfile without 'INVOKE AREA'.

Passing 'INVOKE AREA' defines the operator context, which allows save_mainfile to bring up the file selector.


Change background image in blender could anyone advise how to change background image in different key frames in 2d animation? I need to have one background image on the 1st frame and other images on other frames. If i change a background image on the 2nd frame then it is automatically changed on the 1st frame. It looks like i can have only one background image on all key frames or not?

Sure. Select your Background Image (Empty), go to Properties > Object Data > Image, set the Source property to Image Sequence or Movie and select your clip using the File Browser:

Manual: https://docs.blender.org/manual/en/latest/modeling/empties.html


Align image corners to video corners in Blender VSE I want to add 3 images to 3 corners of a video but I don't want to calculate the correct position every single time. Currently the bottom-left corner is the only one that works as I want, for all the other corners I need to calculate something like (video.width - image.width). Which is easy but it gets really annoying when you're adding a bunch of images with various sizes that could be easily aligned by just moving the origin from bottom-left to top-right.

Is there a way to say "align the top-right of the image with the top-right of the video" in Blender Video Sequence Editor?

I don't think there is currently a way.

It is an easy task for an addon, so I made one. You can get a copy of it from here, just save the link to disk, then in blenders preferences under addon click Install From File and select the script you just saved. Once enabled you will find a panel in the sequencer properties N with alignment options.

Currently it will align the selected strips to the top, left, bottom or right of the frame. I was just thinking that I could add align to active strip as well as centre, so it may also have those options by the time you see this.


how to Viewport mimic? I am using two viewports, one with a render display filter, one displaying solid for editing. I want the viewport of the render view to mimic the rotations of my view that I'm editing in. Is there a way to parent my views?

You can use a camera view. The perspective "camera" is not accessible.

Create a camera.
Set both views to that camera.
In the editing viewport press N to open the properties panel, then check Lock Camera to View.

When you manipulate the view in the viewport, you will not exit the camera, but change its transformation.


Can any one give me tips on how to make a certain material with nodes? My friend who is a car spray painter showed me a photo of this cool crystalized paint job. I thought it would be cool to see if I can do it in 3d. I am completely stuck and I can't find any videos or links on how to make it.

It seems you want to draw triangles going outside a point, lots of them. The basic setup is this:

By fiddling with those values you can get various shapes:

Then you can use a Voronoi texture to get random positions:

Instead of using Voronoi you might want to have a simple mathematical formula to calculate which cell you are in and where's that cell's center - then you can try some tricks like add a transparent color to the color ramp (where the black is currently), and use Alpha as a check if the pixel is "empty" - if so, draw a triangle from the nearest cell. Or you can just use that alpha to merge multiple such textures together:

You could make the stars less regular by e.g. multiplying the gradient texture by the number of triangles, and rounding it to get the triangle number, then e.g. do a modulo 2 to detect if the triangle is odd - if so, draw a black (transparent) pixel - or even better, calculate the distance to the center (the middle line) of the next triangle, so that you don't draw a black line near the center where the triangles overlap. You could also replace Voronoi with mathematically defined slopes ("Multiply Add" -> "Greater than") and allow some triangles to pass it, while some others to not pass it (and then those slopes could be other triangles). Possibilities are endless, though your node count will grow fast.


Model Loses all Vertex Color in Render I have colored my model in Vertex Paint mode, but it loses all coloring once I switch to Render. How do I go about making the color show up when I render it?

Let's say this is the object you have:

Now open up the node editor:

Add the material then, in the node editor add the Attribute node:

Change the attribute label to Col:

Then it will show up in both the material view:

And the Render View:

Hope this helps

Regards
Grimlock


Decrease Movie from 60fps to 30fps Ok guys here´s the deal, we have recorded an video interview with an client, but we forgot the camera settings on 60fps.

This started as a question but how I ended up finding the answer I think I should share since I didn´t find anything related to this subject here.

There´s a way of decreasing from 60fps to 30fps. Today if the movie file is  imported straight on VSE and use 30fps the video will be on on slow motion "off course it´s divided by two times right?".

So the first thing it´s import the file using 30fps:

Now select your movie strip and apply an Speed Control and on the setting use the values:

That´s it now your 60fps file it´s at 30fps and you can continue the editing.


How to extract the normal map of an object? I am totaly new in Blender.

How can I access the normal maps of an object in such a way to have their x, y and z values?

You can access the normal data for your mesh object via the Texture Coordinate input node. From there you can manipulate the vector data with various other vector nodes.


Vertex Group Weight Influence I'm having trouble with understanding vertex weight influence.
As you can see, I have the vertex group painted how I want it.

When binding the armature to the mesh, I used Armature Deform > With Empty Groups and assigned the vertices to the groups. Then I did the weight painting manually. A vertex with any weight, 0.000 - 1.000, is influenced 100%. I don't like this.

It seems the vertex weight is being disregarded. It seems that a vertex with any weight on it at all is 100% influenced. (note: adding a VertexWeight Mod didn't help).

Lind to .blend

The location that you have the issue is the barrier between what gets moved and what doesn't. The mesh faces in this section can easily get stretched too much with the motion of the attached pieces.

I would recommend using a curve object for the hose instead of a mesh. By giving the curve a full fill and a bevel depth and increasing the resolution you get a nice round hose.

To animate the hose you add a hook to one or more of the curve points. While in edit mode select one of the curve points and press CtrlH and select Hook to New Object. This will create an empty at the location of the curve point as well as add a hook constraint. in object mode when you move the empty the curve point will move with it.

The beauty of a curve in this scenario is it maintains the hose shape no matter how far you stretch the points from one another. Parenting the empty to your piston will keep the end of the hose in place.

while stretching the hose too far will create a noticeable distortion you may want to add more hooks to the next curve point and use a limit distance constraint so that the coiled hose picks up and follows the movement.

For the final animation you would want to animate some rotation on the empties to prevent kinks in the hose.

You can look at my simple example file here.


Whats the best way to render a 360 video in blender? So I made a 360 degree video in blender but the quality is terrible.
Does anyone know how to make my video look more HD?

Terrible in what way? You probably need to up the resolution? For 360 you need at least 4096x2048 if you are rendering equirectangular. Problem with this resolution is that it takes forever to render an animation, so a lot of optimization will be necessary to keep your render times in check.


trying to make a wavy edge I'm a beginner in blender and was looking around for learning the basics. I found some videos on youtube (https://www.youtube.com/watch?v=f5Gb1VK98Wc) (the last 10 minutes have what I'm trying to do) and at the end of one a donut is made but the icing is supposed to be wavy on the edge. so when I select the bottom layers and put the setting on random and pull down there are no waves being made. rather the entier layer is stretched down and the top half gets wavy. then when I hide the top half and only use the bottom row of vertices they still just get stretched downwards. any and all help is greatly appreciated!

Two possible scenarios:

Did you select every single vertices on the bottom ring? If so, stop. Just select one vertex when using the proportional editing tool for this. Use the scroll wheel to increase the fall off of the proportional editing tool.

Do you have the subsurface modifier enabled? If not, the random function will make it jagged.


how do you light dark areas okay so, my lighting is being weird and I have several dark spots, it doesn't matter how many lights i have or where i move them, they still persist, its also bugging me that the gloves are the exact same material as the white spots on the shoes, but are look darker.
I've tried changing the environmental lighting too, but it doesn't help

Its probably shading. In the properties>data tick a box that says "Auto Smooth" and try an angle like 30.


Hair Emitter Particles Point In Random Directions I am trying to create a grassy field following a BlenderGuru Tutorial: https://www.youtube.com/watch?v=zhYtJ_VmvXE. However, when I add the hair emitter onto my field to create the grass, instead of pointing upwards the grass particles point in random directions and I'm not sure why. Here is how it looks:

There could be many causes for this problem, from my experience:

Rotation Tab

Your Particle system has an incorrect initial orientation, although this is less likely, be sure to check which one fits best.

Children Tab

Your particle system would probably be using children if you're generating a meadow of grass, as there's a lot of grass. These settings affect the children greatly, and can lead to some very strange things happening, if used incorrectly.

More specifically to your case, it's likely a clumping error.

In such cases, clumping can cause them to bend very strangely, generally toward, or away from the clump.

Velocity

It could also be a problem with your Particle system's velocity.
The Emitter Object settings especially, can cause some pretty outlandish results when used extremely, as they affect the direction and shape of your particles, as well as their origin points, especially in the case of children.

Object Problems

I'm sure that Andrew stresses quite a bit over applying scale, rotation, and location to your models, this is very important.
It's also important to check that all of your grass models are properly lined up, all facing the right direction. Although, in your image, you seem to have Scale, Rotation, and Global disabled, so that is less likely to be a problem than their absence.


Render large 3D graphs (Millions of vertices & edges) I need to somehow render several large 3D graphs where each vertex has a position in 3D as well as edges between some of these vertices. I have an XML file with the graph structure (a list of vertices with corresponding id and position as well as a list of edges given as two vertex ids each) and wrote a script to import vertices as spheres and edges as cylinders. This is working fine for up to 100k vertices & edges but importing millions takes way too long (several days).

I am already using low-level operations, creating one sphere (with minimal segment and ring count) and copying that sphere for each vertex in the list. Only afterwards I update the scene:

# Example data:
node_dic = {0: (0,0,0), 1: (0,1,1), 2: (0,1,0), 3: (1,0,0), 4: (1,1,1)}

# Generate base sphere:
bpy.ops.object.select_all(action='DESELECT')
bpy.ops.mesh.primitive_uv_sphere_add(location=(0,0,0), segments=3, ring_count=3)
ob = bpy.context.object
ob.scale = [0.003, 0.003, 0.003]

# Copy object for each item in the dictionary:
for node_id, node_pos in node_dic.items():
    copy = ob.copy()
    copy.data = ob.data.copy()
    loc = np.array(node_pos)
    copy.name = 'node-' + str(node_id)
    generated_nodes[node_id] = copy

# Create vertex group:
group_name = "vertices"
groups = bpy.data.groups
vertex_group = groups.get(group_name, groups.new(group_name))

# Link vertices to group
for ob in list(generated_nodes.values()):
   if ob.name not in vertex_group.objects:
        vertex_group.objects.link(ob)

# Update scene with group instance:
scene = bpy.context.scene
group = bpy.data.groups[group_name]
instance = bpy.data.objects.new(group_name, None)
instance.dupli_type = 'GROUP'
instance.dupli_group = group
scene.objects.link(instance)
scene.update()

I am doing the same for the cylinders representing the edges of the graph with the additional complication that they have to be rotated properly. As mentioned before this doesn't scale.

Thus my question, is there a better way to achieve something like this? A completely different approach maybe or some optimization I am not aware of?

Okay, thanks everybody! What I ended up doing:

From the vertex & edge lists create a mesh via python api:

# Create mesh & object
mesh = bpy.data.meshes.new("mesh")
obj = bpy.data.objects.new("graph", mesh)

scene = bpy.context.scene
scene.objects.link(obj)
scene.objects.active = obj
obj.select = True

mesh = bpy.context.object.data
bm = bmesh.new()

# Example data - replace with parser
node_dic = {0: (1,0,0), 1: (0,1,0), 2: (0,0,1), 3: (1, 1, 0)}
edge_list =[(0,1), (1,2), (2,3), (3,0)]
index_map = {}

# Add vertices to object:
for node_id, node_pos in node_dic.items():
    pos = np.array(node_pos)
    v = bm.verts.new(pos)
    index_map[node_id] = v

# Add edges to object:
for edge in edge_list:
    bm.edges.new((index_map[edge[0]], index_map[edge[1]]))

bm.to_mesh(mesh)
bm.free()

This allows for very fast import of rather large graphs (several million vertices and edges). Now for visualizing the vertices as spheres or anything else use dupliverts (https://docs.blender.org/manual/en/dev/editors/3dview/object/properties/duplication/dupliverts.html) on that object.
Visualize the edges between nodes by adding a material to the object.


Problem with textures/faces Sometimes one part of my model takes strange transparency and i dont know why.
When i import model to unity it looks even more strange.

What it looks like to me is a flipped normal. When they flip, they often get that slightly darker gray color, and in Unity they will not render at all.
You can flip your normals by in the edit mode, selecting the faces that are looking odd, then at the top selecting mesh, going down to normals, and clicking flip. if all faces are selected you can recalculate them to either face inside or out at the same location.
I hope this helps you.


How to Inset + tweak Depth using numeric input I used Inset Faces I, Ctrl to tweak but I cannot use the numlock key to make it 0.1. When I do that the thickness changes, not the tweak. Is there a different way to do it, or can I use a certain shortcut that I don't know about? I cannot find any other way to do this.

To change multiple parameters for an Operator numericaly, use the Tab key:

Press I to inset
(Optional) Enter numeric value for the Thickness
Press Tab to switch over to Depth
Enter numeric value for the Depth
Confirm operator with Enter


Renaming Animation Channels with a Script I changed my armature bones and it screwed up my animation. I'd like to traverse ALL my animations and channels and change a specific channel name to the updated bone channel name. How can I do this with their API I cant find docs for traversing the animations.

This should do the trick. Obviously, you will have to fill in the complete dictionary of bone name mappings.

import bpy

d = {"oldname1":"newname1","oldname2":"newname2", }
for action in bpy.data.actions:
    #these so called action groups are the bones, ie one group contains all fcurves of one bone
    for group in action.groups:
        if group.name in d:
            oldname = group.name
            group.name = d[oldname]
            for fcurve in group.channels:
                fcurve.data_path = fcurve.data_path.replace(oldname, d[oldname])


Scale Texture with a Value-/Math-Node in my node setup I have a value node. I want this node to influence the scaling of my mapping node.

Is there a way to achieve this? Or is there a math/vector node setup I can use to manipulate the scale of my texture?

I found an answer to my question:
Possible to control a Driver from a Group Node input slider?

Because the original question here is another one, I won't delete my post. Maybe it is helpful for someone.

If you only want to scale the texture, you can use a MixRGB node set to Multiply instead of the Mapping node, as in this example:


modeling a building from one cube I wanted to build a building like the picture and what I did was putting two cubes on top of each other . I want know how this can be made from one cube I mean start from one cube and extrude or ...

Enter edit mode
Hit Ctrl-R to make a loop cut across the mesh.
Repeat in other direction
Select face and extrude it upwards(E-Z)


How to create cylinder with varying radius at different height My goal is to create a imperfect cylinder with a script, where some randomness is added to the radius of the cylinder at certain intervals. I am very new to blender unfortunately, and am lost at the approach to take.
I would imagine I would need to generate circle of vertices, connect them with edges, duplicate and extrude, move points and repeat. However, I don't have the faintest idea of the commends I would need for each step, and would appreciate any help/hints.

Bmesh script.

Here is but one of may ways could approach this.
Rib n Bridge

Make growth_segments cirlcles all with segments segments.  Each
has a radius in range (min_radius, max_radius) and the the next is
in the range of  (min_growth, max_growth) above.
A translation matrix, using the accumulative height is used to place
each successive circle.
Each circle is added with bmesh's create circle primitive. On each
iteration a "rib" is the last added segments edges of the bmesh.
Skinned by bridging each rib with its next.
Finally the first and last ribs are ngon filled with the
contextual_create operator, somewhat akin to bmesh's F
"fill" key.

import bpy
from bpy import context # for testing
import bmesh
from random import uniform
from mathutils import Matrix

segments = 16
min_radius = 0.5
max_radius = 2.0

growth_segments = 10
min_growth = 1.0
max_growth = 2.0

bm = bmesh.new()

h = 0
ribs = []
# make the circles
for i in range(growth_segments):
    bmesh.ops.create_circle(
            bm,
            segments=segments,
            radius=uniform(min_radius, max_radius),
            matrix=Matrix.Translation((0, 0, h)),
            )
    h += uniform(min_growth, max_growth)
    ribs.append(bm.edges[-segments:])

# bridge the loops
for rib, ribnext in zip(ribs, ribs[1:]):
    bmesh.ops.bridge_loops(
            bm,
            edges=rib + ribnext,
            )

# fill the ends

bmesh.ops.contextual_create(
        bm,
        geom=ribs[0] + ribs[-1],
        )

# Create object load mesh
me = bpy.data.meshes.new("RandomCyl")
bm.to_mesh(me)
ob = bpy.data.objects.new("RandomCyl", me)
context.collection.objects.link(ob)
# make selected and active
ob.select_set(True)
context.view_layer.objects.active = ob

Matrices
Have used a matrix in the create circle operator to translate to the height

Here I've extended this a bit further to give a panel beaten effect, each rib is now a random ellipse using above min max for two radii, and also rotated randomly 0 to 45 degrees in Z.
A diagonal matrix is a quick way to produce a scale matrix.
Sx = Matrix.Scale(4, 3, 'X')

is equiv of
S = Matrix.Diagonal((4, 1, 1))

Each circle is transformed by R @ T @ S (rotation, translation, scale)
    bmesh.ops.create_circle(
            bm,
            segments=segments,
            radius=1,
            matrix=(
                Matrix.Rotation(uniform(0, 0.7854), 4, 'Z') @
                Matrix.Translation((0, 0, h)) @
                Matrix.Diagonal(
                    (
                    uniform(min_radius, max_radius),
                    uniform(min_radius, max_radius),
                    1,
                    )
                ).to_4x4() # since tanslation mat is 4x4
                ),
            )

Cannot emphasize enough, the better we become at using linear algebra (vectors and matrices) the "easier" it will be to use API methods. Is also generally faster and IMO cleaner.
Spin Profile
Another way would be to make  profile edges on XZ plane and spin it around z axis to make a solid of revolution.

Equivalent of making profile shown on left, and creating mesh by spinning it with the screw modifier (default settings)
import bpy
from bpy import context # for testing
import bmesh
from random import uniform
from mathutils import Matrix
from math import radians

segments = 16
min_radius = 0.5
max_radius = 2.0

growth_segments = 10
min_growth = 1.0
max_growth = 2.0

bm = bmesh.new()

h = 0
verts = [bm.verts.new()]

for h in range(growth_segments):
    radius = uniform(min_radius, max_radius)
    verts.append(
            bm.verts.new((radius, 0, h))
            )
    h += uniform(min_growth, max_growth)

verts.append(bm.verts.new((0, 0, verts[-1].co.z)))

for edge in zip(verts, verts[1:]):
    bm.edges.new(edge)

# spin the sucker

bmesh.ops.spin(
        bm,
        geom=bm.edges[:],
        axis=(0, 0, 1), # z axis
        angle=radians(360), # 2pi one rev
        steps=segments,
        )


Can you toggle on/off the physical properties of a mesh? I want to hide an object and I also want it's physical properties to be off while it is hidden. Is this possible?

For example, if I have a cube colliding with a sphere and I want to preview the scene without the cube - is there a quick way of doing this without affecting the keyframes etc...

Thanks

In the physics tab there is an option to set the physics to "Ghost" which is a quick way to disable physics without changing any collision parameters you may have set up.

As for hiding the object, in the Outliner View find your object's listing and click the little eye icon. This disables the rendering of the object in the viewport and in the final render/game.

To make the object reappear and enable its physics again simply toggle the listed options again. :)


Removing specular intensity from all materials with internal I've ripped a model from a video game and for whatever reason whenever I import the .obj file all of the materials have an unwanted default specular intensity of 1.000 (I am using the internal Blender Render engine.)

There are thousands of materials, so is there a way to set the intensity to 0.000 for all materials without doing it manually one by one?

This seems to me to be a job for a python script but I'm unfamiliar with both python and scripting inside of blender (maybe I'm wrong about that, anyway).

Any help would be much appreciated. :)

copy the script below, add a new text block, paste, right click, run script.  The specular intensity of all materials will be set to 0.

import bpy

for m in bpy.data.materials:
    m.specular_intensity = 0.0


How do I make the light go behind the Earth? Additional info:

I'm working in the compositing section, and only there it looks like that. If i turn on rendered mode, it will look like this

If you need any more info please ask me!

The lens flare you refer to as "Light" should according to normal physics never be blocked by an obstacle. If you still want this effect tho, you should try to mask out the earth in your post processing. To do this, create a second layer in which you render your earth completely white with your background completely black. Do this, with either the emission shader or an background shader. You also need to render a layer without lens flare. Then you can use your mask and to overlay the flare less render above the one with flare using an alpha over node.


camera doesn't fit my screen? not sure how to call it so I was following the tutorial in the upper screen and I changed my cam from 1980x1080 to 1080x1080. When andrew does it the camera is fitting still in the monitor?view? whatever the term is. but when I do it it goes off-screen. How do I fix this? I don't know if it matters but I am using a 22 and 27' FHD dualscreen and I and using the bottom 27' monitor for blender

Once your camera is placed, uncheck Lock Camera To View and you can move the camera frame around within the viewport.


Multires baking requires a multires object I have an object with mirror and multires unapplied, and I want to bake it with higher details while maintaining optimization, but I get the message noted in the title of this post.

Here are my configurations:

I had the same problem. For me, the "apply base" button in the multires modifier fixed this.


Problem with subdivision modifier making a hard edge have curves between each vert I have encountered a problem while using the subdivision modifier I also have on it a mirror modifier (image below of their hierarchy if that is what's effecting the outcome)

The outcome is that there is a wave like texture/look to the asset. image blow is it without the the wire mesh on and the one below that is with it on. I have tried changing the subdivision mod to being simple but to no avail and I have tried to move the verts about to make them able to work without the weird bendy waves and again to no avail.

Thank you for reading.
Edit the fix I had found was that the creases was only marked at 98% which was the culprit to there being the wavy lines.

Looks more like the topology of your mesh needs some improvements.
Look at this two images and the way they look with a subdivision modifier because of the topology.


How to simulate static vs kinetic friction? Rigid Body simulation allows setting bounciness and friction. Is there any simple way to set friction and bounciness to match real world objects? Real world objects have different Friction Coefficients for static (non-sliding) and kinetic (sliding) contacts which Blender doesn't seem to support. In addition, Blender Rigid Body simulation is (according to name) about rigid bodies only so even though you can simulate a bouncing tennis ball by setting suitable bounciness, it's not physically correct simulation.
For example, let's say we have three 0.1 m x 1.0 m x 1.0 m objects (squashed cubes) made out of wood, steel and styrofoam. How to simulate those? In real world, steel would't easily slide over styrofoam but it would slide over wood.

Numerically, static friction (and the transition between static and dynamic friction) is extremely difficult to model, because of the abrupt jump and the directional ambiguity at the threshold between moving and non-moving.
In general, most friction force models therefore actually set the force to zero around the point of zero velocity!
Keep in mind that the the Blender physics engine is not intended for scientific or engineering purposes. It is rather meant to be comparatively simple and fast.
Therefore, you may have to use creative fakery for the feeling of physical accuracy. Maybe simulate the objects (if necessary, separately), bake their trajectories to keyframe and tweak manually. Maybe you can also achieve more impressive results with softbody simulation instead of rigid body simulation.
Or use a dedicated multibody-simulation software (there are free packages out there, like https://projectchrono.org/), but those are way more complex than blender.


Bodies missing from bones? I have a model that has an armature but the bodies of the bones are missing and there are just these points in space where the tails and heads are supposed to be and these dotted lines between them. If I move the points the rig moves but only that point instead of moving the knee and ankle like other skeletons I made.

Is there a way to create or replicate the bodies of the bones so that they interact with each other correctly and not scrunch up the model? Extruding from an existing bone has a body and works how I expect. I also am self-taught so any links to documentation will be very helpful.

This sometimes happens when importing rigs from other software.
For the bone shapes, simply select all the bones in pose mode, go in Property Editor → Bone Tab → Viewport Display panel. Hold the ⎇ Alt key while pressing the cross icon to delete the custom object from the entire selection:

Then switch to edit mode, and open the Relations Panel. Still with every bone selected, hold the ⎇ Alt key and check the Connected option. Now all your bones having a parent is forced to stay connected with it. Which means you can't move a bone off his parent, and so the bones' heads are on their parent's tail.


Rigify pose Issue Mesh Deforming on knee I have this problem with my leg rigging.

Every time I move it up with IK Leg it would bend the opposite direction which would make my character look like a Centaur. Cool but not what I'm aiming for.

Why does it do that but I think it could be because of how I created my character. I created him facing the back view. So when I added my Human meta rig, I rotated it 180 so it can face backwards.
If that's the reason why can someone please tell me how I can fix that with out starting a new Human Meta Rig?

Here's what happened when I tried to fix it by placing the knee's target in the front instead of the back.

Here's how it looks when I don't fix it.

Thanks for the support Candice babe. But I finally figured it out! Woo Hoo!

Alright so I figured out that my Z Axis in the legs were facing the wrong direction of the Original Human Meta Rig Armature.

So then I was like, That looks wrong. I fixed it but I still had an Issue.

But Then I finally figured out I had to fix the Z Axis of my Foot's Roll. Makes perfect Sense.

So all in all for those of you with this issue.
Look for your armature's Foot IK (Which should be that little bone sticking out from the back of your foot) Find that, click it and press N to open your Window.
Next! Scroll to the top in that window and find Roll.
Change the Z Roll till it's pointing Downwards/Backwards and Bam! You got it fixed.

Tip: Now if you want to make a Horseman Just make your Roll face towards the front or   The Opposite Direction.


How can I get the Solidify modifier to apply after a texture displacement? I'm working on the center cup part of a daffodil, and this is my current setup. I have textures that are mapped such that they displace the geometry the way I want it. I then have a Solidify modifier to prevent the mesh from being "single-sided". This is the result:

However, the problem I'm having is that the textures seems to displace the geometry after the Solidify modifier has been applied, but I want the textures to displace the geometry before the Solidify modifier. I know there's a Displace modifier, but that doesn't give me the fine-tuning control I need and have within the Texture panel. As the textures displace according to the normal, the result is that the edge is thick when I want it to have the same thickness as the rest.

How can I force the Solidify modifier to take place last? Is there another way to achieve the same result?

Displace Modifier

Using this modifier before Solidify is the easiest option.

Since you seem to have tried this, I'll include the blend file for you to inspect.


Having problem with rigify Can anyone tell me how to append a character rigged with rigify properly from one blend file to another, cause I tried to append it and it's not working properly.

In object mode:

Select your armature and its child objects (you can right-click the armature in the outliner and choose "select hierarchy).
Hit CtrlG to create a group of your selection, give it the name you want via F6 (like "character" or whatever's making sense).
Save the file.

Open the file where you need to append your character, hit ShiftF1, navigate to your character's .blend file, go in its group folder and select your character's group.

It should work this way.
The last thing to do: since all the "WGT" objects are imported in the same layer as your character's rig and model and overlapping your rig, I suggest you use the outliner, select all "WGT" objects, and move them to another layer.


FBX not showing current version of mesh I updated my mesh on an animated armature. When I export as FBX none of my changes appear to have been made. When I drag the blend file itself into Unity, the mesh appears perfect. I need to use FBX in Unity however due to diffusing materials, but the FBX is showing the old mesh. I've saved this FBX as a new file, not replacing the old. Any direction on what could be wrong? Thanks

I had accidentally changed the mesh in a custom shape key rather than on the basis shape key - meaning the head enlarged when she blinked! I needed her head to be enlarged for every animation. For future reference, if you want to edit the mesh for all animations (shape keys), ensure you have basis shape key selected in object mode, then go into edit mode. As I had already made the mistake of editing another shape key, I just deleted it, edited the basis key as I should have done, and recreated the blinking shape key.


How do I achieve a particle trail effect? So I was attempting at the "Houdini Trail Effect" in Blender as shown:

but got stumped with the whole particle system.

I managed to create the following through trial and error with the Vortex on each pole, and added Forces to the Emitter (Sphere)

& then this was the result:

I am wondering if anyone knew how to create the Swirly Trails in the Emitter, then maybe convert to spline afterwards? I  know the Ivy Generator is the closest thing but it relies on the Origin Point and etc. I'm not sure if Forces would affect Ivy, but who knows.

Anybody that has a clue, it would be greatly appreciated! I will try again but I doubt I will find a workaround with the Trails.
Thanks!

I think it can be done.

Unfortunately it requires skill.

In this example I used a sphere emitter
and a slightly smaller sphere that had collision physics enables, dynamic painting as a canvas, and a negative strength force field to attract the particles.

The slightly larger emitting sphere isnt rendered, and the render starts after the particles were alive for about 100 frames and had enough time to settle and get going.

So the emitter would drop all the particles and the colliding sphere would attract them and get dynamically painted on its surface.

to make the particles move on the surface, I made three vortex forces. Although in your example it looks like there are six, plus two forces(one on top one on bottom)

I also saw that your example had lots of compositing done ontop of it so I attempted a transition to a bokeh blur...
Have next to zero experience with compositing atm.

Here is the file
But you will need to re-bake the canvas for dynamic painting and set the timeline to start at frame 1.

P.S. temporarily make the particle scale(in particle panel) super tiny before dynamic painting or else you will get super wide paint marks.


How to make water treatment device hatch? I have to draw a water treatment hatch, but since I'm not an expert in Blender  I'm asking for some help drawing it. Or do you know a tutorial where someone has made that kind of hatch already...

I need to model only RED COLORED part- I know how to model the BLACK PART...

This is not your final object but it's a way to get the basic shape:

Put your image as a background image.
In Front Ortho, create a plane, rotate it on the X axis, apply rotation, center it, mirror it on X and Z axis to make a symmetrical 2D copy of the blueprint.
Switch to Right Ortho and extrude a bit.
Select some of the vertical bars and extrude again.
Create a UV sphere that follows the shape of the object.
Boolean the 2 objects with the Intersect option.
You have your basic mesh. Dissolve some edges, merge some vertices...
Add some edge loops to sharp the edges. The knife tool will be helpful.


Weird shadow behavior on mesh I have some weird shadows on my objects. More specific it changes when the angle of view has changed. You can see in the first image the middle cushion is lightened and in the second image is darkened. In the middle view is the same as the others but the problem appears on the sides of the couch. I had checked already the normals (face orientation), double vertices, double faces, I don't have any modifier, smooth shading in the entire object is on, the material is simple as you can see in the fourth image, I have turned off the ambient occlusion, the size is close to normal size of a couch, I have only a point lamp (power 1000w size 1m). In the last image, you can see the appearance of the object in edit mode in render view.
I have windows 10 64 - blender 2.82
I can't get what it causes this issue.

[2

Thanks in advance

Wrong color space for the normal map
First of all you have some object with the normal pointing inside the surface, you can enable the Face Orientation overlay to spot them. I suggest to fix them by recalculating the normals.
Your node setup would be correct if you were using a common Normal Map you can find around the web. Your normal map has been baked with different settings, as you can easily spot by comparing the shades of blue between yours (on the left) and another normal map made from a professionist.
Your is simply baked in another color space. You should ask the person who did it which one exactly is, but if you switch to sRGB instead of Non-Color, all seems fine, so we can assume sRGB is the one.

Here's some normal map from the web: your nuance is clearly lighter.

Solution:
Change this parameter.


White and Chrome ball in material preview mode I'm using Blender 2.9.
How do I display white/chrome balls in Material preview mode?

Be sure to have the HDRI Preview checkbox checked in the Viewport Overlays menu.


Is there an easy way to make a tree in Blender? Is there an easy way to make a tree in Blender? I'd like to have branches that have smaller branches that branch off, but I don't want to go through all the trouble of modeling each branch by converting curves to mesh, then joining them, then turning them back into curves. Any suggestions?

Make a Tree with the "Sapling" Addon

If you want to make a tree in Blender, you can use the built-in addon named "Sapling".

To enable it:

Info header -> File -> User Preferences

Then:

In the search box, type Sapling
Check the checkbox at the right hand side of the addon
If you want to always have Sapling in your Add menu, then click on the Save User Settings button at the bottom of the screen:

To add a tree to your scene:
SHIFTA -> Curve -> Add Tree

Adjust all the settings:

Since quite a lot of the settings are not labeled in any obvious way, I recommend studying
tutorials on Sapling.

NOTE: You MUST set all the settings the way you want them to be before you do ANYTHING else, otherwise they cannot be changed and the tree will stay that way (i.e. it's parameters are not changeable after it is first created.)

Sapling is very versatile and can create many, many types of trees and bushes. Here are some samples:


Wrong loop cuts position offered by blender by default I'm making the arms of my bird, and I need to place some loop cuts in a specific area to match the topology of the arm with that of the body.

The problem is that Blender offers to place the loop cuts in totally wrong places! Can you explain how I can place them where I want?

I attached 2 screenshots:

Or, if Blender offers the chance to correctly place the loop cut, I can't use it because it breaks the mesh, like here:

...and here: (it seems it creates a series of vertices under the existing ones without care about the actual topology):

Since I haven't been able to make people understand what I mean, I am trying again by attaching 3 new pictures to the post.

On the first picture you can see that there are 3 starting loopcuts. The circled one is correctly attached to the end of the arm while the other ones aren't.

On the second picture you can see that at the end of the arm, there is the need to make two loop cuts that should be attached to those you have seen on the previous picture.

on the third picture you can see the loop cut proposed by Blender; that's not right for my needs.

So, how can I make the right loopcuts without too much effort? Thanks. Also, I've attached the .blend file of the bird:

The loop cuts not going all the way around would be the result of the loop cut running into a face that has more or less than 4 sides; an n-gon.

To make a loop cut go in the direction you want, make sure to place your cursor on an edge perpendicular to the direction of the loopcut (cursor is where 3D Cursor is):

These are the basic principles for all loop cut making.


How do I remove doubled faces? Merge by Distance isn't behaving properly I keep running into this problem. I have tried to rebuild this mesh three times now... I'm building a flat mesh on the X + Y Axis only using extrusion Ctrl + E, Shift + Zetc. When I finish I keep getting doubled faces, indicated by the different shading on the affected faces. (I'll attach screengrabs). What is the best way to fix this?

I have tried Clean Up > Merge by Distance, but it removes loads of faces entirely, not just the doubles, and then bizarrely I can't add the face back by selecting the vertices and pressing F. If I select all the affected vertices and delete faces it deletes both faces.

Help in this matter would be greatly appreciated, thank you.

Revisiting this for continuity. And answering my own question. I continued to have this issue, with doubled faces and inconsistent 'shading' on the faces on further mesh builds, using Extraction E to build a flat (2D) mesh.

There were two problems: Duplicate vertices and Normals direction of the faces.

Because it was a simple mesh I was able to remove the doubled vertices manually. But it can also be solved using the command from the 'Mesh' Drop down: Clean Up > Merge by Distance. Although this doesn't always seem to behave perfectly and may still require some manual work.

This didn't always result in accurately recalculating the normals either. One can recalculate normals from the same Menu 'Mesh' > Normals > Flip, Recalculate, Rotate etc. But to do individual faces they need to be manually selected I believe.

To choose individual faces use Face Select mode 3 and Recalculate or Flip only selected faces.

In all of this I wasn't able to figure out why Blender sometimes (seemingly randomly) flips the normals or duplicates vertices, but with a little diligence they can be adjusted as one is building the mesh.

I hope that helps someone who is encountering a similar problem in their early days getting their head round Blender.


How to project UVs from one object to another? How to project UVs form the big object to the small one to display part of the image that is behind it as shown in the snapshot below.

Here is more convenient way to do so:
You need UV mapped object as source and another object with the same texture but any mesh data with assigned UV map as target.
For target add DataTransfer modifier, select source object, enable Face Corner Data transfer as Nearest Face Interpolated and below click UVs as face corner data layers to transfer.

The result quality depends on target mesh density.


Why are these tiles appearing in my final rendered image? I'm rendering an animation (as an .exr image sequence) and some images have these tiles appear on the final render.
It somehow only happens on surfaces that are closer to the camera.
It looks like Blender is somehow calculating adjacent tiles differently in certain areas.

You can see them on this image as the faint, slightly darker squares. The distribution of these boxes in random every render-iteration.

Has anyone had the same problem? I've tried turning denoising off, changing the tile sizes, changing the sampling or changing the light paths etc., nothing helped.

Figured out the cause thanks to @Rich Sedman, so I guess this is a temporary "solution", as it doesn't really solve the problem, just finds a way around it.

The tiles appear in the render due to CPU and GPU handling the output differently for some reason. Deactivating the CPU in the CUDA settings not only solved the issue but also gave me 30 seconds faster render times per frame.

Not sure if that's an issue of the current 2.8 release candidate or just something that comes with combining two pieces of hardware for the same process. (Maybe my Geforce GTX 1080 ti doesn't work well with my AMD Ryzen 7 2700X?)


How do the AV-sync, Frame Dropping and No sync in Timeline work? How do the AV-sync, Frame Dropping and No Sync options in Timeline work when working with audio and video?

They come in help when the animation is too heavy to handle realtime reproduction, affecting only the 3D viewport, not the renders.

No sync means that every frame in the viewport is showed as soon as possible, and a number in the upper left corner of the 3D view tells you the frame rate actually being reproduced: if white everything is OK (I.E. 24 FPS - default), if Red is slower (Maybe 4.67 FPS).

Frame Dropping means that the FPS is always the choosen one (24 - default), and blender jumps from a frame to another trying to remain in sync, actually not displaying (dropping) all the frames between.

AV Sync is used in combination with the VSE, assuring corrispondence between the 3D frame and the VSE frame.


"Extrude poly ribbon" (ctrl+click) not working for me So I've been following this blender tutorial and have just created a head using Dyntopo.  I am now learning how to finish it with retopo.  I started out by turning on snap during transform (snap element: edges, snap target: active), and positioned a small plane the head.  The tutorial then went on to explain how to "extrude a poly ribbon" by selecting an edge of the plane and extruding it by pressing control and clicking, as shown below:

When I try to do this, however, it does not seem to work.  It just outlines the head in orange, as shown:

What should I try doing differently to make this work for me? If it matters, I am using a mac.

Mac: If the answers above don't work for you, try: ⎈ Ctrl⌘ Cmd LMB

In order for ⎈ Ctrl⌘ Cmd LMB to work, you must have "Emulate 3 Button Mouse" checked.

To do this: File > User Preferences > Input tab > check Emulate 3 Button Mouse box