Is it possible to change the axes/part that the vortex forcefield is attracting? INITIAL SITUATION:
So I have a flock of "Birds" that are generated through a Boid Particle System,
at one point in my animation a vertex force field gets activated and the Particles get drawn to it.
My goal is to have it look like the flock of "Birds" is circling around one spot for a specific amount of time.
PROBLEM:
The Vortex Forcefield attracts the Particles at the bottom side of my model, so my "birds" look like they are flying sideways which I don't want.
QUESTION:
Is there a way to change which side of the model is attracted by the Forcefield, or is there a workaround for my problem?
Thanks in advance for your answers and best regards

Well, there is 2 ways to do this.
In the particle settings, go to rotation and uncheck dynamic. This means they all point in one direction.
But I doubt this will give you what you want, its just a quick fix.
The way I find works best is to just take your instance object, enter edit mode, and mess with the rotation and location until you find something that is decent. Rotation works better than location. For it to work, you have to be in edit mode when editing transforms.


How to get rid of garbage data in blend file I'm having a problem that by appending collections from scene to scene (or shot to shot) the blend files are inflating in size (well over 1GB already), although they contain more or less the same content. I found a ton of objects, images and materials in the blend file (Outliner>Blender File) which are not visible in the view layer nor viewport but only in the Blender file, and are often duplicates or materials and images from deleted objects or hierarchies. Purging does not get rid of them, and they are simply too many to figure out manually which ones are needed an what is garbage data. There is only 1 scene and 1 view layer in the blend file.
Is there a way with python to get rid of this unused garbage data-blocks?
Example here:

Finally I found a way do deal with this issue: Atomic Data Manager add-on for Blender by remington creative (free add-on):
https://remington.pro/software/blender/atomic/
It seems that I am not the only one who noticed that something is fishy here.


Sculpting not working I haven't found any solutions to this after searching everywhere. The sculpting just doesn't happen.
The brush is showing. But when I try to sculpt, nothing is happening (I have selected the mesh and then went to sculpting, so that's not the problem).
I have also seen that the sculpting is working on other meshes. I really don't want to start another sculpture.

Select the grab tool (G) and ensure the brush is large enough.
To sculpt properly, you need enough polygons to operate on.
If you don't have them, consider retopologizing via the remesher option in the sculpting mode and experiment with different voxel-size levels (smaller makes more polygons) of to find the outcome you want!
Don't go too low too quickly or you will lose the ability to make coarse changes to the sculpt: One's workflow should begin coarse and become fine over time when sculpting in detail-passes!


Unable to add more logic bricks I recently began experimenting with BGE (Blender Game Engine).

I’ve got a basic character, with a child containing the actual model (the top level character is simply a hidden physics body shape).

The top level character contains all my sensors, controllers and actuators for movement, looking around, etc.

I reopened blender this morning and found that I can no longer add logic bricks to my top level character.

On the “add” menu, every item from each of the options (sensor etc) is greyed out, so does nothing when clicked. I can delete existing bricks, I can disconnect and reconnect things, and the bricks themselves still work, but I cannot add any new bricks.

This is specific to this node, I can add scripts on other nodes,  but not the top level character, or sub nodes of the top level character.

Is this something I’ve managed to change when editing? Or is this some build in limit?

I never had that and I can't imagine what the cause of it could be.

As a workaround I suggest to replace the object, with another one. You can copy the logic via space copy logic bricks to selected (in a similar way you can "copy game properties").


How to rig my character's clothe I just made a hooide for my character but I don't know how to rig it in a correct way. When I rigged the hoodie, it's always clipping to the character's body. (by the way It's blender 2.79)

I can send the blend file ıf it helps to solve the problem.

Your problem is that you can see the body beneath the coat. The easiest method to make it invisible is to use a Mask modifier: Select the vertex group you want to hide, give it a name, give your object a Mask modifier, in the Vertex Group field of the modifier, select the group you've created, then use the arrow on its right to switch (<->). Now your body will be invisible.


Why is my render noisy/blotchy? I'm new to Blender and wonder why, when I render the image, the image is noisy or blotchy.

The render result is shown below.

You can see the effect clearly at the skin area.

Can someone help me resolve this issue?

It looks like denoising artifacts due to low render samples settings.
Go to render properties tab and increase the number of render samples.

The idea is to keep the render time low and the image as good as possible. More samples will increase the render time and quality.


Access elements of matrix(vectors and Euler angles) in Animation nodes using script node I would like to know to access individual elements of a matrix or matrices from Matrix/Matrix list input in the script node. Then I can perform some operations(experimentation) on those elements and then send them to output as a Matrix/Matrix list. I would like to do similar with Euler angles and Vectors. I am very new to programming and have searched this forum and coudn't find anything to do with this with regards to animation nodes.

Here are some examples for creating and decomposing each type:
Vector and Vector list
from mathutils import Vector

# create Vector
x = 1
y = 2
z = 3
new_vector = Vector((x,y,z))

# extract individual elements
x_element = new_vector.x # new_vector[0]
y_element = new_vector.y # new_vector[1]
z_element = new_vector.z # new_vector[2]

# create AN vector list
new_vector_list = Vector3DList()

# append element to vector List
new_vector_list.append(new_vector)

# get element from vector List
first_element = new_vector_list[0]

# get first element's x value
first_vector_x = new_vector_list[0].x

Euler and Euler list
from math import radians
from mathutils import Euler

# create Euler
x = radians(30)
y = radians(45)
z = radians(60)
new_euler = Euler((x,y,z)) # Euler((x,y,z),"XYZ")

# extract individual elements
x_element = new_euler.x # new_euler[0]
y_element = new_euler.y # new_euler[1]
z_element = new_euler.z # new_euler[2]

# create AN euler List
new_euler_list = EulerList()

# append element to euler List
new_euler_list.append(new_euler)

# get element from euler List
first_element = new_euler_list[0]

# get first element's x value
first_element_x = new_euler_list[0].x

Matrix and Matrix list
from mathutils import Matrix, Euler, Vector

# create matrix
location = Vector((0,0,0))
rotation = Euler((0,0,0))
scale = Vector((0,0,0))
new_matrix = AN.utils.math.composeMatrix(location, rotation, scale)

# extract location
extracted_loc = new_matrix.to_translation()

# extract rotation
extracted_rot = new_matrix.to_euler()

# extract scale
extracted_scale = new_matrix.to_scale()

# create AN matrix list
new_matrix_list = Matrix4x4List()

# append element to matrix list
new_matrix_list.append(new_matrix)

# get element from matrix list
first_element = new_matrix_list[0]

# get first element's location
first_element_location = new_matrix_list[0].to_translation()

# get first element's x location
first_element_location = new_matrix_list[0].to_translation().x

# get raw matrix element
matrix_first_element = new_matrix_list[0][0]

I suggest you to look at blender api documentation for more information.


Visible seams on tangent normal maps I'm having a small issue with visible seams on normal maps. The map was painted on Substance Painter and has no weirdness around seams. When I plug it into a Normal Map node set to Tangent Space this happens:

(it's a horse underside)

When I set the map to Blender Object Space the seams become nearly invisible, as they should be, but the shadows also looks awful.

What can be done to minimize the issue? I need to be able to use maps on tangent space. Moving the seams or hiding them under other stuff isn't always feasible.

Substance offers two options for normal maps, DirectX and OpenGl. DirectX is the default (normally set when you first setup a project). The difference between the two is that the green channel is inverted from one to the other. Blender expects normal maps in the OpenGl format.

There should be options in Substance Painter to export with the OpenGl format instead.

You may need to look at export presets to do this:
https://support.allegorithmic.com/documentation/display/SPDOC/Creating+export+presets


When I render, the color changes This is a 2D intro title animation of a couple of solid color geometric figures (rectangles, circles etc.) moving in layers on top of each other, and put the camera right overhead. They are all in purple-ish colors. When I run it with the "play animation" button, the colors are what they should be. But when I render it (ctrl + F12) to a movie, all the colors are changed to green-ish colors. It's really only the color of the figures that changes, not the entire video.

When I render each frame to a picture, there is no problem. But there are over 400 frames, so that is impractical.

As noted by @DuarteFarrajotaRamos you have a node in the compositing that is altering the result.

You have a Hue Saturation Value Node changing your color.


Can you transfer weights partially in blender? I'm trying to transfer weights from one mesh to another, but I don't want to transform all of the weights, just one in a specific area. Is there any way to do this, or will I manually have to replicate it?

You can copy the vertex group (the weights) to the selected object from the active, if they have the same geometry, then you can remove the unwanted weights easily, by selecting them and click on remove in the Vertex Groups tab.


Best way to model the top of a rook piece? I'm having problems modeling the crenels (battlements, castellated parapets) of a rook piece. The basic modeling is easy, the problem comes with subsurf modifier. I can't achieve the shape I'm looking for.

Any combination of bevel, edge loops, creases, gives me artifacts, or I lose the circular shape in the top view.

Here is the blend file, if you want: http://www.pasteall.org/blend/31339

You never want triangles on a mesh you are going to subdivide as they will result in pinching.

The images above seem to have some, introduced by the bevel tool probably.

Using a pair of edge loops to sharpen the rings, and then a pair of edge loops top and bottom per crenelation you can get close to the shape you want. But there is some blockiness when you look down from top view.

If you want a smoother circumference, you can

-select the face loop you have inset near the top and hide them. (Hiding faces will prevent edge loops from continuing past them when added.)

-Add some additional "spoke" edge loops as shown. As there is one ring hidden, the loops won't cross the entire object, creating some ngons in the inset area.

-Scale the new short edge loops up just slightly on the not z. scale the entire section above the hidden faces down about half that much to split the difference

I know, I just said don't use triangles and then here I go introducing poles in to your mesh, but they are nicely tucked away, it works and it's easy :P

http://www.pasteall.org/blend/31346

Source: I just finished watching 4 hours worth of topology videos by Jonathan Williamson, the cg cookie guy.


Simulated hair isn't affected by force fields? I have uploaded a blend file with a "Wind Blowing Hair Test" and it is my hope that perhaps someone can offer some assistance. I utilized a UV Sphere and applied a particle system along with a pair of "Force Fields - Wind" and the hair falls to the bottom of the sphere leaving the top bald while the wind force retains little movement. Any ideas would be great!

Hairtest.blend
http://www.pasteall.org/blend/29535

I noticed two issues with the wind forces, they are quite weak and they are facing the wrong direction.

The affected axis (under Falloff, next to Power) was set to -Z (in local coordinates), but the force fields have their positive Z arrows pointing towards the object.

Increase the strength and set the axis to +Z:


Blender 2.79b Grease pencil brush hotkeys not working (Windows7 ,64bit) So,while using Blender 2.79b Grease pencil brushes  (on Windows7 ,64bit) , I tried using the number (1,2,3....)default hotkeys assigned to them  and found they were not working.Then I changed the hotkeys to other unique keys so that they didn't match with other operators  still the brush hotkeys where not working.
Any solution?

Finally ,there were some old files from previous versions of blender lying in Program files directory.Deleting them and reinstalling blender worked and now grease pencil shortcuts work.


How to toggle material view mode by hotkey (similar to Alt-Z/Shift-Z) I want to be able to toggle "Material" view mode by using hotkey.
Shift + Z toggles rendered mode and Alt + Z toggles textured mode.
I want my hotkey to toggle material mode.

I tried to assign a new hotkey with the following command I copied from console window:

bpy.context.space_data.viewport_shade = 'MATERIAL'

But it didn't work.

You can add the new shortcut by :

go to User_Preferences > Input > 3D_View > 3D_view(Global) > Add_New
setup the new shortcut as follows ( ⇧ Shift + Q are just an example choose your own ) :


Make blender unaware of user/system installed add-ons I am running a customized, local install of blender from and with a script:

./blender --background --python generator-blender.py --

My customized local install of blender is prepared with add-ons that might also be present in the user/system add-on locations, which currently leads me to (e.g.) blend4web being found once as a locally installed add-on and once more as a user-installed add-on:

multiple addons with the same name:
'/home/simonrepp/AXIOM/elmyra/lib/linux/blender-2.76b-linux-glibc211-x86_6/2.76/scripts/addons/blend4web/__init__.py'
'/home/simonrepp/.config/blender/2.76/scripts/addons/blend4web/__init__.py'

How can I tell blender to ignore the user/system installed add-ons and rely solely on what is present in the local install i have set up?

In my customized, local install I needed to create an empty config/ folder inside the 2.XX/ folder (the one that contains datafiles/, python/, scripts/ already - in my case 2.67/). As soon as blender sees this folder it completely ignores any user/system add-ons (and everything else too I suppose - startup files, configuration, etc.)

I found the answer here: Need guidance for creating no dependancies between two installs of Blender


Can I import a .vrm model? I'd like to import a .vrm model. Is there any plugin that allows this?
I'd also like to know if it's possible to convert a .vrm to a .fbx or something else, however just being able to import it into blender is good enough.

if you change the extention from .vrm to .glb and open in Windows Paint 3D, you can then export it to FBX and import to Blender.


When to texture paint to paint on Mesh and when to use Photoshop to paint on 2D Texture I recently found two workflows for texturing, painting directly on the model and painting over a 2d texture file. In what situations are you supposed to use which? I have noticed that it is hard to texture seamlessly with PS when there is a cylinder with a wood texture. In this case it feels like texture painting is the way to go. Is this correct?

Or is texture painting the newer way of doing things? And 2d texturing is outdated?

The concept behind UV unwrapping is to assign to every 3D vertex a 2D coordinate.

If you are working with a flat plane, the two approaches are nearly the same (generally a 2D software is more powerful).

If you're working with a 3D object, direct painting on the 3D mesh is gratifying but generally it's difficult to get a really powerful control of what you're actually doing.

Working on 2D UV unwrapped textures is more controlled but more complex, at first.

Like many tasks, you can reach your goal in many different ways: the complete path for texturing a cylinder is:

1) create seams on the mesh, unwrap it, assign an  image texture (the seam will be visible)

2) delete seams, create new different seams and create a new UV map

3) bake the texture on a new image

4) doctor the new image in a 2D editor (seams to be doctored will be visible, don't touch image's boundries, as it would create new visible seams)

5) use the new image with the 2nd UV map

This complex procedure will assure a seamless texture in any situation, generally it can be avoided by hiding the seams in hidden places.

As you can understand there is no "better" or "old" way. It depends on your needs.

Personally, i stopped studying 3D paintings because even a simple open source software as GIMP let's me reach better results than Blender Paint capabilities.


boolean union having problem when combining cubes with same height I tried to union 2 cubes , this supposed to be very easy task, but fail at some point. (cross object on the left) So i create union of two identical box/cube , i reposition the second cube so it cross each other and it works great. But in the right side, i tried to do the same thing but this time the cubes has different size but still have the same height so their top faces will be overlapped each other.

So i select the bigger cube, add boolean , pick the smaller cube, set to 'union' and set solver to 'bmesh' ( i tried carve and doesn't give a correct result). So they looks correct, but when i applied the boolean and go to edit mode, there're some overlapped interior faces which is not what i want, i can delete the faces but what is wrong ? how to fix this ?

Thanks

edit :
note:  to reproduce the error , the smaller cube has to have same height as the big cube , so both top faces have to overlap each other.

Select the large rectangular add boolean modifier. Select the object (small rectangular). Operation as union.


How do i add faces back into my model I accidentally deleted all of the faces at some point and i can't bring them back, it looks like wire-frame mode but is not

The first place I'd check would be your Object Properties -> Viewport Display options. See if Display As is set to Wire. If so, set it to Textured or Solid.


How to cut a hole in a mesh like this without using boolean I have this mesh

I need 3 identical holes in front face. How to do this keeping good topology?

I tried to use boolean modifier, but there is terrible topology at the end and I need to apply subsurf modifier before applying boolean

P.S. I'm also used subsurf modifier

If you want big holes it can be something like that (needs one more edge though). Delete the face, create 8 vertex circle, duplicate 2 times, fill the gaps with some F:


How to split a beveled surface to two parts to use different materials Recently I asked this question and got a very nice answer:

What is the easiest way to smooth the intersection of two planes?

However, now I would like to use a different material for each face. Could anybody help me on how to do this? Written in python script would be best.

Thanks,
Mojmir.

No script here but this is a possible node setup:

to get this:


Armature with no deformation? I'm looking to create a simple animation.
Where sphere are moving and rotate

but when I'm parenting them to the bone I get deformation on them.
I tried to weight paint in blue but same result.
I tried to use the Empty group as explain in this video. : https://youtu.be/eF4CuIX40XE

What am I doing wrong ?
project here : https://drive.google.com/open?id=1tc3AgbKAzb-9KU3-iu3UngiwGwwrC2LD

Best
Z

This what I get when using "Bones" relation
I'm totally confused about this result I don't know what to do to resolve this

Here's how to set up what I think you want to set up.  (I used 2.82 Alpha, but it should work on any >=2.80).

Start with an empty scene.  Add an armature consisting of a single "Bone".  In edit mode, extrude a second "Bone.001" from the tip, and extrude a third "Bone.002" from its tip.  Switch to object mode, and add your spheres.  In wireframe, it should look like this:

Now, LMB select the bottom sphere and Shift-LMB select the armature.  Ctrl-Tab switch to Pose mode, click the bottom bone.  It should look exactly like this, with the bottom sphere as the secondary selection (dark orange) and the bottom bone in the armature selected (light blue):

Finally, Ctrl-P Set Parent to Bone.

To parent the second sphere, Ctrl-Tab back to object mode, LMB select the middle sphere, Shift-LMB select the armature, Ctrl-Tab switch to Pose mode, click the middle "Bone.001", and Ctrl-P Set Parent to Bone.

For the final sphere, Ctrl-Tab back to object mode, LMB select the top sphere, Shift-LMB select the armature, Ctrl-Tab switch to Pose mode, click the top "Bone.002", and Ctrl-P Set Parent to Bone.

You should now have each sphere parented to a single armature bone, using Bone Parenting.  In pose mode, each bone should control one sphere with no deformation of the other spheres.  Here's the blend file:


How to make node disappear It seems to make the value node disappear while connecting it to group input. I've tried different combinations and have node wrangler on but I'm not sure how to get it. I'm also unclear as to exactly what it does, that you couldn't do without the shortcut. From this video.

First they use a Node Wrangler shortcut.  They're doing a Shift +  RMB and drawing a line over the two noodles coming out of the Value node.
This command combines the two noodles into a Reroute node that splits out to its two destinations.
Then they delete the Value node and bring a new input over from the Group Input.  Essentially they've recreated the Value node as a slider on the node group.


How to edit Geometry for extrusion I'm trying to model this character's helmet as an exercise, and I've reached a snag. As you can see from the photograph, the geometry behind the gem cross straight over the helmet, but as it stands, the edges on my sphere all converge at the center, making it very difficult to get a clean extrusion. I'm currently experimenting with dissolving that center vertex and then quadding the remaining hole so I can manipulate the loops more easily, but I feel as though there must be a better way. How should I go about editing it to rectify the issue? Thank you so much!

Yeah, UV spheres aren't generally the start of great topo.  There are times when they'll work, but more often than not, they're just headaches.

Consider using what I call a cube-sphere:

I started out by subdividing my cube with 2 cuts (so I can get that center stripe), then used the "to sphere" operator (which I use rarely enough that I just call it from the spacebar search, so I don't know the hotkey.)  Give it the full factor (1.0) for the to-sphere, and you've basically shrinkwrapped your cube to the surface of a sphere.

I've got two levels of subdivision in that pic afterwards.  You can write your subdivision as you go and need more detail, but as always, it's smart to work from low detail to high detail, from big to small.  I think you'll find that a lot of your extrusions come more easily from starting with topo appropriate to what you're going to end up with.  (Of course, you can always retopo afterwards too.)


Blue lines coming out of vertices Hello,

I clicked something and these blue lines appeared. How do I hide them?
The lines are coming out of the vertices

It looks like these are the Normals of your object vertices. Display the right panel with N > Mesh Display > Normals and disable the Display Vertex button:


How to switch colors on Base Color Image Texture Node? I downloaded this Sci-Fi Drone from the internet and I want yellow and black color to switch places so that drone is mostly black with less yellow. Is that possible? Did I even correctly connected PBR textures?
Drone's color is from the Base Color Image Texture Node.
Drone and textures download link: https://www.cgtrader.com/free-3d-models/aircraft/other/sci-fi-camera-drone
Here's my Material Setup.

Any kind of help is appreciated! Thanks!
My blend file:
This is how the drone should look. It differs a little bit of mine because there's no reflection in the front part.

Material Nodes
For switching simple image you can try something like this ...

Compositor Nodes
But for your texture would be better use Compositor with some Matte nodes to extract colors more accurately (or use any other image editor that supports color selection).

Yellow-Braun

separate color by Matte node, Desaturate, Invert, ColorRamp to adjust final black color

Grey

separate color by Matte node, Invert, RGB Curves or Color Mix node to make it yellow

After that, mix them together with Alpha Over node on top of original image where are stored Blue Black and red parts of texture. Save and use as texture in material.
version 01

version 02

Notes:

To get more freedom in adjustments could be better assign material to different parts of the mesh as unique material (with the same textures). Like that you can easier to let rid of yellow lines on black surfaces just without need to mask texture since material is assign just to that part and not the others.

Anyway I highly recommend to use some image editor than node system. In Photoshop could be done with masked yellow-braun layer, and grey layer, recolored above original, just in a few minutes. Only two layers, each with just two adjustment layers. And easily adjust mask manually for some details if needed.


Making an object fall with cell fracture I'm trying to make an object fall to the ground and shatter.
The object is already fractured using the cell fracture add-on.

But in the beginning of the simulation the object is exploding to pieces.
What I want is the object falling and when it hits the ground, it should break apart.

To touch on why your object your object is exploding at the beginning of the animation, check the Collision Margin in the properties panel>physics>rigid body>rigid body tools tab.If it has been changed at all, this can affect how the simulation works.

If the collision margin sensitivity is ticked on and too high, (1 is the maximum) the fractures are literally pushing away from each other, thus the object explodes right away. Creating the effect you're looking for will take just a few steps:

Step one is of course to fracture your object, in my example .gif below I used a sphere.
Step two is to add rigid body physics. Delete the object on layer
one, and move the fractured object from layer two to layer one, or
just work on layer two. Select one fracture, go to the tool
panel>physics tab and click on add active.

Next, select all of the fractures and click on copy from active.

Now you need to add a collision object, so that the fractured
object has something to shatter against. Add a plane and go to the physics settings in the tool panel again, and click add passive.

Now, drag the fractured object to the height you want it to fall
   from, and press Alt+A, and something like this
   should happen:


Why does the sub surf modifier round off only one side? My subsurf modifier is only rounded on one side, anyone know why?

Thank you to 'Gorgious' for the answer!
"With the geometry selected in edit mode, type SHIFT + N to recalculate the normals"


Both side of the Weight Painting went to the right side I went back to work more on my project which is building a character for my game.
I made the weight painting already, but I wanted to edit my mesh, and then adjust the weight paint too if it's needed. However after editing the mesh, the weight painting went crazy on all the bones along the limbs:
The weights disappeared on the left side, while the right side of the bones has all the weights for both sides.
You can see an example of my problem on the image below: While the upArm.R bone has the weight paint for itself and for the upArm.L bone too, the upArm.L bone has no weights.
I would avoid starting over the weight painting process since I polished it a lot from time to time. Can anyone help me?
-Peter

To answer to my question if someone is stuck in the same situation:

The source of the problem:
I thought it was a bug but it's not. While editing my mesh I made a mistake: In Edit Mode, I used the Mesh/Symmetrize tool. I didn't think that it would not only mirror the position of the vertices, but their weights too! I believe using the Mirror Modifier instead would avoid this.

What's done is done, let's fix it!
In the Object Data Properties panel you can see all your Vertex Groups. They are assigned to bones by having the same name as them.

First, I made a copy of all the Vertex Groups that are inside of the right limbs. (Arm.R_copy)
Then, I erased the Vertex Groups in the left limbs. (Arm.L)
Finally, I renamed the copies, so they would assign to the left limb bones. (Arm.R_copy -> Arm.L). So far, every Vertex Group has its weights, but also the opposite side. Let's get rid of that!
Select the LEFT half of your model. The easiest way to do it is to use lasso selection with X-Ray turned on (Alt+Z). Now, go through all the RIGHT Vertex Groups and click Remove, so the unecessary weights will be removed.
Select the RIGHT half, and do the same with the LEFT Vertex Groups.

-Peter


Diffuse BSDF texture on cycles doesn't reflect the Hdri in some parts? i was creating a 3D Eye on Blender and i added a Diffuse image texture map, and it reflects an Hdri image, as you can see, the blue part of the eye doesnt reflect this (fig 1.), it's weird since it's only a single geometry with a single texture...It is possible to make it look better, like the image is reflected on all the geometry? (fig 2.)
Does anyone know what to do?
Or how can i make the Fig 1. looks like exactly the Fig 2.?

The reflection is working properly, the problem is that your eye model is not a perfect sphere. the area that is extruded inwards distorts the reflection.

To make it look like a physical eye you will need to create another sphere outside of the one you have and set it as a glass shader. then you will have the reflections you want.


Adding Custom Menu "Run Script" Button Causes Duplicate Is there a way to use the Blender Text Editor for adding a custom menu and not get a duplicate every time I click on "Run Script" to test the menu? For example, in the text editor, load the template like so:

Template -> Python -> UI Menu

Then notice every time you press "Run Script" you get another menu in your main menu bar. How can I update my menu without getting a duplicate?

I tried simply commenting out register() but then new updates don't show up.

Execute Reload Scripts F8 first before re-running the script.

I think a custom menu function is supposed to run within an addon, where register() and unregister() are run in pairs. Each script execution yields different instance of each functions, even if their name doesn't change across each execution. So unless there is a way to check existing draw functions within a class by name (which I haven't found yet), Reload Scripts or restarting Blender is the way to go.


Should I model eyelids? sort of a dumb question that I may already know the answer to, but should I model eyelids on a character that's gonna be able to blink?

I guess you have 2 main approaches:

The eyelids are parts of the face mesh. As Hikariztw said you'll animate them with bones or shapekeys. Not easy to do but for a realistic character it's the only solution.

The eyelids are part of the head object but they are separate meshes. You'll rig them to bones and make them go up and down, or rotate, or even just appear and disappear (move outside/inside the head mesh). It's not a realistic solution, so it's good for a cartoon character, and it will be much easier to animate.


Blender mesh becomes messed up after importing Alright, so I have this X wing model that was created in a separate game file, and I want to move it to a main game file with other models where I plan on making a game.  The thing is when I move it, it looks normal enough.  However, when I hit key "p" to play the game as a game render, everything on it looks messed up as far as placement goes.

So this is what it looks like after importing it into the game--as it should

But this happens after entering the game, pressing "p"

As you can tell, normal perspective is all messed up.

I am really confused as to what's going on and have played around with import settings, with no luck.  I would really appreciate it if someone could help me out.

Thanks

It figured it out. It was all in the textures and I had to delete them all and then and add them back into the game.  When you import a obj into a game sometimes the textures and materials get messed up.  I just deleted all the material slots and recreated the material and uploaded the same image to be mapped on it.


'to sphere' giving eliptical shape What is causing this effect? Same thing is happening when I try looptools -> circle.

The problem is due to the mesh having been resized without applyig the new scale and the solution is to Apply Scale. This can be achieved by selecting the object (in Object mode), pressing Ctrl-A and selecting Scale.


Proxy vs Library Override I'm after some guidance on best practice and options here.
I have a character model in blend file A, it is a collection of separate objects. There is also an armature. The various objects which make up the character are parented to the bones of the armature. This is a robot character so I don't want any mesh deforms; the parenting is sufficient.
As part of the character, there is a point light parented to one of the objects.
I don't want to join the objects because:

It is more manageable to edit separate objects
Some have modifiers which I don't want to 'apply'
They lose their parent bone, which is all set up nicely

Now let's say I want to link to the character from blend file B. I choose link, and link the collection which includes the rig and all its child objects.
Now; how should I go about animating this character? I can see two options:

Make a proxy - I can make a proxy of the rig, and great, I can animate it, however

I can't animate the light brightness
It sounds like proxies are going to be deprecated

Use a library override, however

It bring in everything as separate objects, which is unmanageable when I just want to animate the whole character and hide the implementation details

Can anyone offer any guidance here, what would be the standard or best practice way of doing this? A link to a tutorial would be a very valid answer.
Many thanks
Pete

I would use a proxy if you want to keep everything as light as possible. As for the light, you could put it in a different collection in the character file so it doesn't get linked in and then append the light so it's locally in your animation file.
Library Overrides are like an advanced proxy technique. Yes, every single object gets imported and that can be a little overwhelming at the beginning. So you could just add a new child collection in the character file where you throw all the objects in to organize the outliner a bit better. Library overrides have the huge advantage that you can still access each part on its own so you could add modifiers on them in the animation file. Another usecase would be if you're using render layers and you want to separate your character to different layers. For example: I'm working on a vfx shot with a drone that has a laser beam. Using library overrides I can put the laser beam on its own render layer and bring it back in compositing to control the intensity of it.


How can I prevent force fields from affecting hair or other particles? I want the turbulence force field to only affect my smoke sim, but it's also messing up my hair particles. I've tried setting Effector Collection to the collection the smoke simulation is in (the hair is in a different one).

EDIT: project file - https://drive.google.com/open?id=1O7bqU8FNCZyATB6S46CRcYuGLIb2OSEb

I set the effector collection to the collection the hair emitter is in and the hair stopped moving. You should set it to the collection that the hair is in instead of the collection the smoke is in.


Blender 3D Space mouse settings I’m a 3ds max user trying to migrate to Blender 2.8 but having some problems setting up my 3dconnexion SpaceMouse Pro device. The 3D mouse settings that show up in Blender (when pushing on the SpaceMouse menu button) seem to provide everything needed (at first glance) but eventually every combination of settings I try does not get me to the desired navigation behavior.

What I would like to get is a comparable behavior like in 3ds max, Side FX Houdini or 3D Coat. Those apps (and most of these apps) seem to be using a target camera and the target always moves to the tings active or selected, resulting in a form of selective orbit guided behavior.

Blender seems to provide two main options, a free floating camera behavior (having no target) or a fixed center point orbital rotation mode?

With the free mode I’m having problems keeping the objects centered in the view-port while smoothly rotating around them, however this mode allows me to move to different parts of the scene although not very smoothly (its erratic without guidance of selective target locking and reducing sensitivity makes moving slow). When I try the orbit and trackball option the behavior is comparable to a locket target camera but in this mode I cannot move to different parts of my scene (not able to zoom in to different objects and rotate around them) due to a fixed center.

I tried locking the view to the 3D cursor and then manually move the 3D cursor, this brings me a bit closer but panning sideways or up/down is not possible and eventually manually moving a rotation point is just not what I’m looking for, preferably having a target camera with auto-lock to selection behavior but camera and target are still able to move up/down or sideways withing the perpendicular viewing plane of the camera.

If someone knows right combination of settings to make this happen then pleas let me know?

(using Windows 10 pro 64bit)

PS: big shout-out to Blender developers, its unbelievable what this community have done so far.

When it gets difficult to navigate select the object you are working on and hit the "." on the num pad and it re-centers around that object.  Not perfect but makes it a little closer to usable. I'm a Solidworks user and love my 3D mouse.  Seems to work a little closer to normal but is a little slow in rotating around the object but slow is better than flying off the screen.  I'm a newbie to Blender but starting to love it.

Edit......
Attached are the settings I found to be the most like Solidworks movement. But if you start losing control hit the period on num pad after you have selected the object you are working on to get back functioning. You can play with the Free/ orbit and the Turntable but I like Free and Trackball settings for total movement.  I did have to increase the Pan and Orbit Sensitivity they were to slow.


Scale locally in blender 2.8 I know how to scale along local axis (hit x or y or z two times), but how to do it in blender 2.8? Thanks.

EDIT:
made question more accurate.

Set your Transform orientation to Local

Press S and X, Y or Z

And then 2, Enter


Setting the location of my object I have accidentally applied the location of my object in blender and my object has now zeroed out. How do i fix this?

If you know exactly what location you had your object at previously, you can go into edit mode, with your cursor on the origin, use Selection to Cursor (Keep Offset). Then, back in object mode, change the position again to the same place it was before.

If you don't know the coordinates of its original location, you could just estimate them, or you could, in edit mode, press N, and average the locations of the individual vertices to find the original position, but that would be a lot of work.


Exporting fire animation as mentioned in the title I want to export my fire animation as Collada(.dae), but this makes my smoke domain an actual cube. Any idea how to fix this since I dont want any smoke at all?
Thanks in advance

Unfortunately, i don't think that's possible to bake a particle and export it as a collada file. If i'm not mistaken you can export it as .mdd to modo, but exporting it to an external game engine or something like that is not supported


Can the full features of Blender be used with a trackpad? I'm not interested recommendations for the best hardware, but whether Blender's full functionality-- all that zooming and selecting stuff-- can be realized with only a trackpad.

On modern Mac OS X, it seems you can:

Two-finger vertical scroll to rotate along horizontal axis perpendicular to view
Two-finger "spin" to rotate around up axis
or Two-finger horizontal scroll to rotate around up axis
Two-finger pinch to zoom
or CTRL + two-finger vertical/horizontal scroll to zoom
SHIFT + two-finger vertical scroll to pan along up axis
SHIFT + two-finger vertical scroll to pan along horizontal axis perpendicular to view
RIGHT click and drag to translate selected object
CTRL click and drag to lasso select


Any blender GUI toolkit for use with Game engine? Is there any blender GUI toolkit/library (popup window + eventual window control, button, radio button, checklists, slider, enter text...) to use with blender game engine.

The purpose is to evoke, for example, a button, place it at a given coordinates, then add the appropriate sensor, controller and actuator.

There is a library called bgui that makes creating GUI for the bge much easier.

There are two locations for the documentation, the old (but better) google project wiki and the read the docs page.

In a nutshell, add the bgui script to your project with a python controller in the logic editor. Use a always sensor to trigger the script to always run.

Next you add widgets or components to bgui with a line such as this (this will add a button).

# A FrameButton widget
self.btn = bgui.FrameButton(self.frame, 'button', text='Click Me!', size=[0.3, 0.1], pos=[0, 0.4], options=bgui.BGUI_DEFAULT | bgui.BGUI_CENTERX)


Create Realistic Lips Without Sculpting Them From Scratch? so far I've gotten pretty far in my character creation process and I've managed to create everything on my character without having to sculpt anything from scratch. It's a realistic-looking character and so far he looks pretty decent with procedural shirt and pants textures, procedural leather, a procedural face pore texture, and for the wrinkles in the clothing, I didn't sculpt them from scratch. I created the wrinkles in the clothing with the Blender sewing system, then, I only sculpted out imperfections and cleaned up stuff.

I feel like after all this work I've reached a stumbling block and that's the lips on my character's face. Is there some sort of maybe combination of procedural texture + real-life texture I can use to create the lips from scratch without sculpting? I tried to take pictures of my own lips and create a sculpting brush using the anchor sculpt tool, and it ALMOST looks okay but not really (I created my own brushes for my characters' hands and they turned out pretty nice). I took the lips pictures with my 1080P Panasonic G6 camera and I'm afraid maybe the quality isn't good enough? I also tried texture painting my lips, but the quality was too poor for it to look good.

How can I create realistic lips from scratch without sculpting and without downloading someone else's lips texture from the internet? I've gotten this far without doing anything like that and I'd like to keep it that way. I'm not looking to create a 100% realistic lips texture just something that looks good enough if I angle the lights in the right places for photos and videos. Thanks in advance for any ideas.

So I actually figured out how to do it. For anyone who might be interested in my process, here goes. I realized that the picture I took of my own lips was a poor quality picture because the lighting was uneven and that caused a lot of bumpiness when I anchored the image on my character in sculpt mode. When I used a picture with even lighting, it automatically looked way better and needed a lot less clean up. To prep this photo, I used Gimp to create a high-quality image for the sculpting brush I created in Blender 2.82.

As far as settings, I used the Clay sculpt brush with the full strength of 1.00, Mapping is set to "Area Plane," Stroke method is set to "Anchored" in the remesh section, Voxel Size is set to 0.1800, and I did have to do some massive clean up for the face, but they were small details that needed to be removed. Lastly, I did need to use the "Crease" brush with "Stabilize Stroke" on with default settings. I also used the "Grab," "Snake Hook," "Nudge," and "Smooth" brushes to get the shape correct and the texture even. Since I have multiple copies of my character saved, I used the original copy of my characters' face as a reference to correct all the facial proportions after the lips texture was finished (Images used as sculpt brushes will slightly change the proportions of the character).

I sculpted to remove details that were incorrect leaving only details that looked pretty decent to me. This is by no means hyper-realistic but that's not my goal. It looks good enough for me and I'm happy with it. I still need to properly color the lips and create a gradient for all the colors, but this picture shows how it turned out. For anyone who only wants to use sculpting to remove unnecessary details without actually having to create the detailed creases of the lips from scratch, this is what worked for me. Hopefully, this helps someone.


How to make ripped/torn cloth? I want to make a simple tear in a piece of cloth (the cloth itself was made with the cloth sim) Ideally, the torn strip should hang realistically, but I don't need it to be animated.

I'm aiming for a threadbare look, as shown below, with the little bits of string fuzz around it.

I also need the torn fabric to be hanging down, not just a hole in the model/texture.

Is there a tool or add-on to do this "simply," other than manually modeling it? If I do have to make it by hand, how should I go about doing it?

I would combine the two options above, and use use the V key to rip edges in edge select mode to outline the strips that will fall. I would still suggest alpha texture to get the edge roughing and then possibly look at the stuffed animal tutorial on CGCookie, using particles for the fuzzy stuff. Of course, the cloth sim would need to be rerun or manually unfold the strips. You might add some weight to the vertex group to make them hang.


Export multi-pass .exr image sequence from cycles? Is it possible to export an image sequence (in this case a sequence of .exrs) from cycles?

For example, I have multiple sets of .exrs for different passes I want to combine into one set of .exr image sequences.

To save all the passes for each frame into a multilayer OpenEXR:

Add an Input>Image Sequence node and use that to import the OpenEXR sequence

Add an Output>File Output Node and set it to Use OpenEXR multilayer and plug the outputs of the Image sequence to it.

You still need a valid output for the render. So create a dummy file, a jpeg file will do. You can erase those later.

Then just set your frame range and render as animation (ctrl F12)

(and remember to erase the jpeg dummy files)


Center viewport key in Blender breaks the viewport I set the key layout to Maya's to work faster, everything goes great.

But when using F key (i don't remember which one is in blender, but the center viewport position and rotation to selected object).

Then everything goes wrong. I'm not able to get near the object. The position where the camera gets centered is another , far from the object. Their pivot point is where i want to look, but the vew goes away, and moving is a nightmare.

Moreover, when trying to approach the object i wanted to center on, the camera gets slower and slower (as in Maya) but I'm not able to get there...

Is there a bug or something? What do you suggest me todo, instead? but not turning to blender layout, please. :-)

I had this problem like this early on.  It's because you're in perspective instead of ortho mode and in perspective the viewport behaves differently, it never goes in close to the object you're zooming, in ortho mode this doesn't happen.  Perhaps I'm over simplifying; but it behaves as you're saying on the 'when I move closer, I don't get any closer" I don't know about Maya.  If this is the issue, simply hit the number '5' on the number keypad in Blender key layout to switch between Ortho and Perspective, you want Ortho. if User Preferences are organized the same in Maya as in Blender, this would be under user settings: Input/3D View/3D View (Global)/View Persp/Ortho if you need to change user settings for Maya, or see what they are.


Split Screen Video- My videos combined won't render with sound? I looked all over stack exchange, and I couldn't find an answer. So I'm making a video where there is two of me in the same video, by taking two separate videos and combining them. My video with sound renders individually correctly. When I combine it with the other video, combined they don't render with sound. I also did everything I could: turned on "AV-sync", turned on the audio codec, etc... and everything.

Now, I am just confused.These are the properties of the combined videos I am trying to render into one video. What am I doing wrong? Yes, the audio is turned up as well... thank you. Here is both of the videos in the VSE:

Your Audio strip is muted (your green "roasting_me.005" strip is very transparent). Just select it and hit Alt+H to unhide it. Or unhide it via the Strip menu. Then it should be rendered in your Video as your encoding settings seem to be correct.


How do I set up a complicated rig correctly for linking? (Advanced) I have recently completed a complicated rig, and within its own file it works brilliantly.  (Yay, me).

My problem comes when I Link it into another file.

Everything is Grouped, and I link its Group from the new file.

Everything gets linked in, however... apart from the base armature a lot of the wonderful additions I've given the rig no longer work, such as the Hide Menu, or the extra armatures for the damaged state.

My question is this: How do I properly set up my rig so that, when I link it, everything works?

I'll go through my process step-by-step, below.

Firstly, here's how I understand simple rigs to work when linked:

When the Amature, Mesh and extra Controllers are Grouped together the Linking process goes swimmingly:

Using the above diagrams as a basis, here's how my new rig differs:
(FYI: my actual rig is a tank, not a person).

There is an extensive Hide Menu which is used to switch on/off various controllers, meshes, damaged states, etc.

Because there is different state changes to the rig, it uses three other armatures parented to the main armature.

There is also Deformer cages over different parts of the mesh which have various controllers "hooked" to it.

So, not simple, but not SUPER advanced either.  Here's what happens when I Link this rig to a new file:

Essentially, all the parenting breaks, and my list of Proxy options balloon out, forcing me to set things individually:

The Hide Menu is the one that kills me the most because I had a terrific Location Constraint placed on each of the switches, and once the proxies have been pulled in the visibility drivers still work (which is excellent), but the Location Constraints do not (meaning that the little switch can now be dragged far from the menu)>  The Damped Track and Copy Rotation of the Hide Menu also doesn't work, which means that it won't automatically face the camera anymore.  Not to mention that all the elements (50+) need to have each of their proxies set individually, which is an unworkable solution.

Right now my Outliner of the Rig's file looks like this:

00_GUI = All the GUI elements for the Hide Menu.

00_RIG= The armature containing the entire rig elements.

STG_  = Stage elements

ZZZ_JNK = Mostly just the custom controllers for the bone shapes.

All of the Rig's elements (including the Hide Menu) are Grouped together, which is what I've been linking from the new file.

I would be very appreciative if someone could set me in the right direction in terms of setting up an advanced rig properly so that when it is linked in to a new file it works as it does in its original file.

Cheers,

Mat

Take a look at this:

Rigging question about Spline IK and having all controls on one armature

It's an example of rig structure with multiple armatures inside parented, to avoid dependency issues.

The trick is to have all the controls the animator will interact with inside one master armature, and to copy these bones with constraints to the other armatures where they do things. This way, you only need to make a proxy of this master armature when the rig is linked and everything else becomes inner workings of the rig.

This should remedy any parent breaking problems when creating proxy rigs.


Blender file from Blender 2.49 to 2.79 when rendering changes default screen layout I used Boujou and a script in Blender 2.49 then opened the file in 2.79. Now when I render, I get redirected to a different screen layout:

And my composite that adds the video background doesn't load as well in this view unless I re-open the Composite Node editor.

Is there a way to do something similar to reset the settings to a project in Blender 2.79?

This is a wild step in the dark since I haven't used 2.49 in quite a while. But there's two things you can try.

Make a new file and append the data you need from the other file with SHIFTF1. That way you should be able to isolate pretty well what is broken and what isn't.
You can disable 'Load UI' when loading the old file.


Camera position and rotation while following path I have a camera following a path, by using the "ctrl+p -> follow path" method. I noticed that during the animation, the camera position and rotation shown are constant (they are the ones the camera has at the start of the path). I actually need the camera position and orientation for every frame of the path. Is there a way to obtain that information?

You can bake the animation and clear parent to get the transform data of the camera.

Select the camera, and in Object menu select Animation>Bake Action

Then in Bake Action menu enable Visual Keying and Clear Parents.

That will bake the location and rotation of the camera for every frame into an action.


How to achieve vapor or steam effect with smoke sim? How can I achieve this effect of a plume of vapor with the smoke sim or other tool?

Result:

Basic setup:

Change Blender units to Metric.

Create Circle (Shift + A > Mesh > Circle) with 2cm Radius and Fill Type > Ngon.
Press Space and type in "Quick Smoke". Select it.
Position domain as in the picture:

Change Light Paths > Volume to 2. It will allow light go trough smoke thus it could be white.

Smoke Domain:

Change Resolution to 64. Higher resolution = more details.
Behavior > Temp to 0.4. Smoke will rise higher.
Behavior > Vorticity to 4. Smoke will have more 'wrinkles'.
Check Smoke Adaptive Domain.
Check Smoke High Resolution and change Noise Method > Strenght to 1.

Material:

Use this node setup:

You can control smoke density by changing Multiply value.

Final thoughts and .blend file:

You can play with Resolution and/or Smoke High Resolution Divisions to get more detailed smoke.

You should save your file and change Smoke Cache to OpenVDB > Float (half) it will speed up whole setup.

To play animation hit ALT + A or first Bake it under Smoke Cache.

Note that I'm using HDRI for lighting, it is packed in .blend file.


Subdividing Causes Strange Edges / Issues on Shape So I have this flat shape, and I'm trying to make it 3D. It's pretty round and has a ton of vertices. My end goal is to have the 3D shape with smooth edges.

I approached this by pressing ALT+F to fill the shape. It created a bunch of faces that don't look too clean.

Then I extruded the shape once forward, and once back (from the original shape) so that it was "3D". This is close to what I want, but I want it to have a subdivision modifier, so the edges look smooth.

I then applied a subdivision modifier, and the shape just looks awful. Bumpy and ugly.

If I do "F" instead of ALT +F, it still produces a poor result.

I've tried looking on this forum for solutions to similar issues, but so far not much has worked. I hope the images are enough to paint my issue, and give an idea of what I'm trying to achieve, any help would be appreciated.

It's not the best topology but just quick example.

First thing I've done was to delete half of the mesh and add Mirror modifier to reduce work.

Next I've created Outer Edge Loop just by extruding vertices.

In the same manner I've filled rest of the mesh with faces with some Reduction Loops, this was needed for making all of the faces quads (more on this you can find on topologyguides.com).

I haven't used any "automatic" methods, it's just extruding E and filling F with a little help from F2 add-on. It's all manual work.


Are billboard particles with animated textures possible? This seems like the kind of thing that would be easy, or at least possible, but I'm having trouble finding information on it.

As a test I've created a PNG image sequence of a sparkle, shimmer, or whatever you want to call it.

And you can imagine what this might look like on an object:

Here is my node setup in Cycles, which displays and animates on UV-mapped meshes, but so far has not worked at all with particles. It uses the black-and-white image sequence as an alpha mask.

Here's a .blend of
my material and particle settings.
The image sequence can be rendered from this .blend.

What I want is for each particle, once it is born, to start on frame 1 of the PNG sequence, and either die or stop animating at the final frame 20 (which is blank). So each sparkle would appear for a brief flash and then be gone. And I am hoping Blender is clever enough to treat each particle's image sequence as unique and beginning at a different time relative to that particle's spawning, not relative to the scene and twinkling all together in unison.

For now I want to do this in Cycles, but in the future probably in Blender Render too. So mainly this is a Cycles question, but solutions for Blender Render are also very welcome.

Thanks in advance for any help.

There are two parts to this question: making the particles face the camera, and then making the particles animated. I will address each separately.

Billboard Particles

This functionality is currently not supported in Cycles. That is not to say, however, that it is impossible.

One simple approach is to parent a plane to the center of mass of the object, set a tracking constraint to the camera, set the particle system to dupli-object, and enable parent rotation to the particles:

With this method, not all of the particles are technically facing the camera perfectly. But I have found that the camera has to be pretty close to the object for it to be noticeable, so unless you are using a fish-eye lens or are trying to get macro shots, this should be acceptable for 99% of cases. The distortion also adds a bit of randomness to the size which can sometimes be desirable.

The other approach is to create another scene which renders using the internal engine, wherein billboard particles are supported, and then link the two objects. For this to work, you will have to configure a camera in Blender internal which functions the same as the one you have in cycles. This can take some time, because each engine deals with camera settings differently. Here's a Reddit post going into more details if you wish to do this.

You could also probably develop a script or a add-on which adds functionality. Unfortunately I don't know enough about Blender add-ons to detail this approach any further.

Animated Particles

tl;dr: there's a node in Blender called Particle Info which can be used in conjunction with a sprite-sheet to animate particles using some Math.

I'm surprised that people have deemed this "impossible." It just takes a (complicated) node setup. I'm going to assume you know some basic discrete mathematics to set this up. You will need a custom mapping node, which you can either download or make yourself from this post. You will also need a Math.floor node which you can, again, either make yourself or download in this pack.

The first step is to convert your image sequence into a sprite-sheet. You can either manually do this in Photoshop or write a simple script to do this for you. This tutorial will detail how to do this with just 1 row, as seen in my example:

Note that it is perfectly possible to have more than one row, but it just takes some extra effort in the node editor.

Next, create a plane set it as a dupli-object for the emitter. This will be the master particle. UV unwrap the plane and configure it to be exactly the size of the first particle as shown here:

The only thing left is the material. As it turns out, there's a node in Blender that gives all the information necessary to create animated particles like this called the Particle Info node. I was surprised I hadn't known about this already, since it seems so useful. The two values we want are Lifetime and Age.

The approach will be different depending on how you made your sprite-sheet, so a basic knowledge of math functions will be useful. You can find many guides to dealing with spreadsheets in game design online, but I don't think its necessary.

The basic approach is to translate the uv mapping of the plane depending on how long the particle has been alive. So, for instance, right as the particle is spawned, it is on frame 1 (and has been translated 0 pixels to the right). Halfway through, it will be on whatever the middle frame is. So, if there are 16 frames in the animation, it will be on frame 8, and will have been pushed 7 tiles over.

The node gives us lifetime and age. Dividing age by lifetimes gives a ratio from 0 to 1 that corresponds to how long the particle has been alive. Multiplying by the amount of frames in the particle animation gives a number that corresponds to the amount of tiles the uv needs to be shifted to the right, plus some extra decimal information that isn't necessary (since you never want to translate the uv, say, half of a tile). You can cut this off with a Math.floor node, giving all the information necessary to make it work.

Hopefully that all makes sense. Here's my node setup (applied to the plane) for the example sparkle animation with 16 frames shown earlier:

This divides the age of the particle by the lifetime, giving a percentage of how complete the animation should be (as detailed earlier)
This multiplication corresponds to how many frames there are in the particle's animation
You have to floor this so that, for instance, you don't shift over by half of a tile
This is the amount to slide over for each tile. For me it is always the reciprocal of the amount of frames, because a value of 1 will wrap around an entire time. I recommend using the Node Wrangler add-on to mess with this node directly to figure out the right value
Simply plugging everything into the custom mapping node in the x category, because there is one row

This will ultimately give you a vector which you can use on the sprite sheet as an image texture, which you can then use in your material as normal.

My final result (with some custom scaling and some other changes in the emitter) looks like this:

Note: I sometimes worry that I'm being patronizing to those that do know math, but I also understand that a lot of artists do not know much math, so I'd like to explain the node setup rather than just handing it out and not explaining it. Please tell me if my explanation is confusing and I will be happy to clear it up!


How to make a curve smooth in the Graph Editor when you restrict the frames of the noise modifier I applied a noise modifier to the Z location of an object, but just to a certain frame range. My problem is that the z location in the Graph editor has a sharp point (making the movement of the object not smooth in the animation). I tried change the settings of the noise modifier (the phase and the offset) but it's impossible to make it fix, so I was wondering if there is another way to do it (like an interpolation or something)

In the noise modifier you can try to use the ease out option of the frame range restriction, that should blend between the noise and the rest of the animation (the value is the number of frames of the transition).
If this does not solve the problem you should upload the file.


Why texture size must be multiple of two? Why in all video tutorials people create textures with sizes like 1024x1024 or 2048x2048 or like that? I understand that this numbers related with powers of two, but why I cant use texture 800x800 for example? It will be works slower or what?

Good question.

By ensuring the texture dimensions are a power of two, the graphics pipeline can take advantage of optimizations related to efficiencies in working with powers of two. For example, it can be (and absolutely was several years back before we had dedicated GPUs and extremely clever optimizing compilers) faster to divide and multiply by powers of two. Working in powers of two also simplified operations within the pipeline, such as computation and usage of mipmaps (a number that is a power of two will always divide evenly in half, which means you don't have to deal with scenarios where you must round your mipmap dimensions up or down)

This is a quote by stackexchange user "user1430", who answered the same question here.
Hope this helped :)


Rigging a rabbit character I have a problem rigging this cartoony character in Blender, particularly the mouth and eyes, and applying shape keys.

I want create this shape for its big mouth:

and the part of the eyelid that goes down

Please answer me in plain language, because Google Translate and my English is not very good.

Thanks

Just an idea more than a real answer, but for that very special case, you should try something like that (sorry for the very quickly done rabbid..) : the trick is to have a ability to have very few points to animate and to be easily able to stay around the wanted shape.

As you can see, very few vertices :

But all rely on a capsule metaball that I have deformed a bit :

1 : the capsule shown
2 : the capsule drawn as bounding box only

Now the rabbid has some modifiers (from top to bottom) :

Subsurf : because we have few points to animate but want it to stretch smoothly
Shrinkwrap : the most important part here as this modifier allows to stay along the capsule (see below for more explanations)
Solidify : to give it some volume

For the capsule :

Add it : Shift+A then choose 'metaball' and 'capsule' (surely you can also make your own shape instead)
Give it more precision (picture below)
Then convert it to mesh, with Alt+C, then 'mesh from curve'

Now edit it a bit in order to give it the wanted shape (to say it quickly, larger on top, smaller at the base).

We want the rabbid head and face to follow the capsule shape, but not the ears or the eyes. So add a vertex group to the rabbid. Assign this group the head part only and name it 'capsule'. Then, set this vertex group in the shrinkwrap modifier as seen two images above.

Now create your shape keys as you need :

The same kind of thing could be used to allow the eyelids to follow the eyes.


how to make an operator toggle? We can use properties provided by bpy.types.Panel.layout.prop(..., toggle=True), that provides a toggle like behaviour it.

but, how to bring this toggling behaviour for buttons? There's no toggle functionality for, bpy.types.Panel.layout.row().operator(...).

An operator is not a property.

Setting the  toggle behaviour for a Boolean property's layout, changes the markup to a button look, rather than a checkbox As with the checkbox it changes  when setting from True to False or vice versa.

An operator layout is rendered as a button which calls the operator, rather than setting a property.

Code can be attached for  when a boolean property is updated.  See example here https://blender.stackexchange.com/a/147144/15543


How to create parallel edge loops I want to create a tiled floor look.
I'm hoping there is a way I can do that by making an square shaped loop of vertices inside each of these squares.

But then again that would mean I'd have to do that for every single square...

Is there an easier way to do this? please let me know.

I want something to the effect of this

Use the Inset tool (keyboard shortcut i)

Set it to individual


Phantom Faces and Normals I have a mesh that had some trouble spots where I had extruded faces into the mesh and It left some extra faces that caused dark spots when I rendered it.

I've gone through and deleted all the faces but the dark spots are still there and when I show faces normals the direction indicator is there but no face to delete.

Removing doubles will merge vertices that are close together, in your case you still have duplicate vertices that are further apart than remove duplicates is configured to merge.

You can increase the merge distance used by pressing F6 or looking at the bottom of the toolbar region.

You may also want to switch to vertex select mode to see where the extra vertices are and either delete them manually or move them closer so that remove doubles works, snapping can be used to move them to the same location for merging.


Why the same object looks different in render / solid view? Why it looks different in render / solid  view? No modifiers etc.


Rendering Environment pass without Combined pass in Cycles Using Cycles,I have a scene with Volume Scatter shader connected to World Background and an HDR image connected to the surface, Rendering the scene while checking Environment pass is giving me a nice full black image "naturally" even with Transparency enabled in the the Render > Film, so far it's understood, so I'm planning to separate the procedure, making a render for the combined pass, then another for the Environment pass with the Background shaders disconnected in order to get the Alpha. The problem is Cycles re-renders the Combined pass in the second step, even by having it disabled in the Render Layers > Passes. How come? Why is Combined pass rendering while being unchecked? In case I'm not doing anything wrong, yet this is the way it is, is there a turn around?

You can't use both volume scatter and a background in the world settings at the same time (read this post).

The workaround is creating a "domain" object around the area where you need the volume scattering. In order to be transparent, the domain will have no surface and only volume scattering.

Your HDRi world texture can then be used normally (Keep in mind that volume scatter will make things a bit darker so you might need to make your light sources and environment texture brighter).

(HDRi by Giant Cow Films)


Cell Fracture not appearing when activated I just installed the latest version of Blender v2.72 because I wanted to play around with its cell fracture addon.

I go into user preferences and check the box to activate cell fracture. Save Preferences and exit the menu.

I go into edit mode and select the cube in the scene and look for cell fracture on the left tool menu and it is not there. In all the tutorials/demos I have seen of this it has always just appeared in this menu.

Is there a step I have missed?

As GiantCowFilms said, the cell fracture addon is used in object mode:


Iterate over custom properties without searching? If I understand the way it works, accessing a property by string (data["propname"] = 0) requires the system to search for it. Iterating over all of the properties in data, comparing the id-string until the correct one is found. But what about when we are already iterating over every property?

for key in a.keys():
    a[key] = b[key]

This type of situation seems like it would be very inefficient. Especially if every access requires a search. Even if some type of hashing is automatically kicking in, it seems pretty wasteful. Is it possible to do this in a way that makes more sense? Some type of property iterator? Or any type of index or reference to the property that relates to the next one in the same structure?

If not, would it be possible to build any type of lookup table or helper utility for a situation where you need to iterate the same set of properties for many objects?

It is correct that accessing values by key using .get() on bpy.types.struct iterates through the elements. The function that gets called through the Python API is pyrna_struct_get() (bpy_rna.c). It uses IDP_GetPropertyFromGroup() (idprop.c) which in turn calls BLI_findstring(listbase.c). As the name already suggests it performs string comparisons by iterating through a list.

It should be avoided iterating over the keys and then accessing the values, both in Blender and also Python software that uses actual dictionaries as data structure. As batFINGER suggested you could use a.items() instead.

for key, value in a.items():
    # do something with either key or value
    pass


Can I have some tris in my model made up of quads? Firstly, I dont have that much experience with blender or 3d modelling. Im making a character for a unity project and would like to know if my model should only be made up of quads or is it ok to have some tris in it as well.

I only ask because I've been ending up with a few tris when I'm near to completing the model.

Also what are some ways of converting tris to quads manually.  I have used the "tris to quads" option without success.

Thanks for the help.

Unity only struggles with N-gons, which are polygons made of 5 or more vertices, so you shouldn't have problems if you have some triangles in your model.


mystery dot unknown problem hello I've been modelling a face only got from the eye brows to the mouth. around the left eye there's a dot that is visible only in object mode not in edit mode I thought it was a vert that some how got there after going to edit mode though it was not there when selecting the face the dot seems to also become selected but still not visible in edit mode when clicking on the dot in object mode it also selects the face so they must be connected somehow I have a mirror mod and a sub surf on the mesh

You don't just have a Mirror and Subsurf modifier on your mesh, you also have a Particle System. The dot you are seeing is one of the emitted particles.

To remove the particle system (as it sounds like you didn't intend to have one) first click the highlighted button below to go to the particle system settings:

Then click the minus button to remove the particle system from your object:


What is the minimum size requirement for a Fluid mesh object in a Fluid simulation? What is the minimum size requirement for a Fluid mesh object in a Fluid simulation? I've heard and read that if the mesh is too small, it may not act like fluid properly when baking. But, I don't know the exact measurements of "too small". Does anybody know?

This is dependent on resolution.

Imagine the domain as a grid of 3D pixels (volumetric pixels, or voxels). If your fluid object is smaller than a voxel, then it can't be represented properly (even if it's two voxels, that's still not good)

To fix this, you can either increase the resolution (this will increase bake time), or scale down the domain (this shouldn't increase bake time, but obviously there is less room for the fluid).

Since the resolution defines a fixed number of voxels, scaling it down will give you the same number of voxels, but they will be smaller (making the fluid object relatively larger):

There may be a hard limit of how small you can go eventually, but anything remotely reasonable should be fine.


How to bend a plane? Bend won't bend I have a subdivided plane (why I need a subdivide modifier and the primitives don't have poly count option is beyond me but I digress)
that I want to bend 90 degrees on the X axis.

I looked in google and found out (I think) how to achieve this but I get the following result below, the plane won't bend it will just rotate in the most unpredictable way. So what Am I missing?

Thank you!

EDIT -
Thanks guys for helping.
I want to bend something like the image below (side view of the pane)

I tried to to do the same in Edit mode and the plane does bend,
but no matter where I place the 3D cursor I get some weird results.
and it won't really bend they way I want. I don't understand how to control it. I tried many 3D cursors positions and starting view angles. (left, perspective, top) i just don't get it.

Thank you!

There are several way you can bend objects.

If you want to use proportional editing, you can use the following steps.

First add a subdivided plane and switch to edit mode. Activate proportional editing. I think linear falloff is the most suitable option for this task. Switch the pivot point to 3D cursor.

Place the 3D cursor where you want the bend to pivot. You can set the 3D cursor to the position of a vertex by selecting a single vertex and then SHIFT+S > Cursor to selected.

Now select the row of border vertices that will be bend. Press R to rotate, followed by the axis you want to rotate around (X, Y or Z). Adjust the radius of the proportional editing influence by using the mouse wheel.

If you want to use the Curve modifier, you have to use the following steps.

First add a subdivided plane and a path (Add > Curve > Path).

Select the path and switch to edit mode. Bend the path so that it represent the bend profile. In the screenshot I have rotated one half by 90° around the Y-axis centered in the 3D cursor.

Then switch to object mode and add a Curve modifier to the plane. Select the deformation axis. The grab the plane with G and X, Y or Z whichever is you deformation axis and move the mouse cursor until it has the desired shape. Alternatively you can do it the other way around and move the curve.

If you want to use the Simple Deform modifier, you can use the following steps.

First add a subdivided plane, then add a Simple Deform modifier to it. Change the mode to Bend and set the axis to the one you want to bend around.

Now switch to edit mode and select the vertices you want affected by the modifier. With the vertices selected go to the object data tab and create a vertex group. Assign the selected vertices.

Add the vertex group to the modifier.

Switch back to object mode and add an empty (Add > Empty > Plain Axes) and set it as Axis, Origin for the Simple Deform modifier. Rotate the empty by 90° around the axis you want to bend. Then adjust the angle in the modifier to control how large the angle of the bend is. The empty is used a center/pivot for the bend so you can adjust the position to change the radius of the bend.

The Bend tool is a bit unintuitive because depends on your angle of view, the angle between your mouse cursor position between the start and end of the operation, the distance to the 3D cursor and uses the 3D cursor as pivot.

First step is to add and plane and subdivide it. Then switch to edit mode.

Place the 3D cursor where you want the bend to pivot. You can set the 3D cursor to the position of a vertex by selecting a single vertex and then SHIFT+S > Cursor to selected. Alternatively you can switch to orthographic perspective (Toggle with Numpad 5) and view the scene from one of the sides e.g. from the top Numpad 7. Then place the 3D cursor using SHIFT and right click into 3D space.

Once you have that prepared, select the vertices in your plane that you want to affect with the bend. Switch to the perspective from which you want to bend, e.g. if you want the bend to occur along the Y-axis, align your view to the Y-axis.

Press SHIFT+W to activate the bend. Now place your mouse cursor at the distance from the 3D cursor that you want as radius for the bend. Move your mouse cursor around the 3D cursor until your reached the desired angle of bend and confirm by clicking the left mouse button.


Can't texture paint properly Every time I try to texture paint a character it messes up in some way. Ive tried multiple unwrapping methods but every time the paint will bleed over into other parts or wont paint at all and ill get seems

Right here all I did was air brushed the hand and it shot right over to the chest area. The UV islands are no where near each other. It makes it impossible to work with

https://i.imgur.com/tRx1n5r.png?1

It is difficult to tell without the actual Blender file, but in the image provided, some of your UV islands are in fact overlapping and others are quite close together.

To fix this, select all of the faces in edit mode and then, with your cursor over the UV window, hit Ctrl + P. This will automatically arrange the UV islands. In the 3D viewport window, in the tools panel (far left of the image), you can then set a margin, which you'll want to avoid this bleeding.

Additionally, you can set the bleed amount option in Texture Paint Mode to 0px, but this may cause problems later on. Especially if you want to use a subdivision surface modifier on the model.


How to add a realistic flare How do I turn the little emission sphere into a realistic flaring sun. (This piece is animated with all the planets rotating and revolving)

You can use the Fog Glow in the compositor to produce a nice glare for the bright sun as follows :

I've used two levels of the glare node which isn't ideal (as it's not the most efficient method) but it provided a simple means of filtering out the 'bright' elements of your original image (since it's a JPG is doesn't include brightness values > 1.0 - in your actual scene you could use an emission material with, say, emission strength of 20 or so - this way the threshold on a single Glare node can do the job!) to be multiplied up by the 'Divide' node (by dividing by a small value - eg, divide by 0.05 to multiply it by 20).

The final Glare node then adds the actual glare on those elements picked out by that first stage to produce something like the following :

To include this in the render pipeline my preference would be to enable the Emit pass in the Render Layer. This provides you with an additional output from the Render Layers node for the emission materials only. You then only need to use a single Glare node for the emission before adding it into the rest of your render.

You can vary the glow by adjusting the Divide node and/or the Glare node or by varying the brightness of any emissive material in the scene. If you want to exclude certain emissive materials from the 'glare' then you can use the Glare node's Threshold to filter those out - ie, setting it to, say, 5 will result in any emission at a strength of less than 5 not being subject to glare while any greater than 5 being subject to the glare.

An alternative is to apply the glow directly to the rendered Image and to rely on the emission strength to provide the glow. This makes for a simpler compositing set up but you lose the ability to easily adjust the glow effect - you would need to adjust the actual emission strength rather than being able to simply adjust the "multiplier" (Divide node in the previous example).


Limited Dissolve changes vertex positions? Carry over from a youtube video comment here
In the video, the presenter manually fills in an example with edges to make faces. A commenter suggested using Alt-F to fill and then Limited Dissolve to reduce the mesh. As this is a video on precision modeling, I was surprised to see vertex positions of the bevels and circles on a simple 10mm plane with 4 holes were changed.  Is there a way to dissolve edges without changing vertex positions?
Blend file for reference; 1 degree + 5 degree dissolves

Edit: Thanks to Robin and taking a second look, I realize now that Blender uses single precision floats instead of double... so that explains my scripts output differing. Don't use 5 degree (default?) with Limited Dissolve and you get great output.

Thanks to Robin, his script, and taking a second look, I realize now that Blender uses single precision floats instead of double. In the first python script, it is printing whatever python thinks (double precision).

Don't use 5 degree (default?) with Limited Dissolve. This lead to original vertices being deleted.
Less than 1 degree limited dissolve doesn't have this problem.


Why is the Displacement Modifier not doing anything? I'm doing the CG Cookie Tutorial on the rocket ship. I added a cube, added the triangulate modifier, added the displacement modifier, added a cloud texture to the displacement, set the displacement strength to 5.0, and yet my cube still looks like a cube.

In the tutorial he ends up with a cube resembling this:

Here are the texture settings:

Remove all modifiers from the cube and start again.
First, add a Bevel modifier. This gives supporting geometry, so when you add a Subdivision Surface modifier, the cube doesn't turn into a sphere (Try for yourself if you don't believe me).
So, add the Subdivision Surface modifier next, (this gives extra geometry to displace - I set number of subdivisions to 3 to start).
Lastly, add the Displace modifier, pick the cloud texture, set the strength to 0.5 and you should get this:

So, the order of modifiers (from top to bottom) is Bevel, Subdivision Surface, and lastly, Displace. You can control the detail of the clouds by increasing the subdivisions of the Subdivision Surface modifier.
If you need to triangulate, you can add a Triangulate modifier afterwards.
EDIT- Is this more to your liking?

If so, all I did was subdivide the cube once, then I placed a Bevel, Displace, and Triangulate modifier in the order shown. You can play with both the Bevel values as well as the Displacement Strength and Midlevel to get different shapes and sizes.
As for the colors - they are in user preferences - Theme is "GreenHorizon"


How do I make text that looks like it is made out of a ribbon? Anyone Guide me. I am a beginner of Blender, i want to make 3d image like below one, i have created 50 of this image (except 2 ribbon curve), and i used modifier tools too. Kindly give me better tuts

The base is to use a Bezier curve with a bevel object (which needs to be a curve too).

For the overall shape curve, add it by : ShiftA then choose 'curve' and 'Bezier'.

For the ribbon curve, add it the same way and flatten it : enter edit mode Tab, then scale it 0 along Y (as its shape is by default curved on Y) SY0.

Come back to object mode Tab.

At this step, you have two curves like this :

Now select the first one (overall shape curve) and assign it the second curve as bevel object (in the geometry part of the curve tab, as shown below) :

You can see that the ribbon curve is propagated along the overall shape curve.

But the ribbon is a bit large, so scale it down a bit : select the ribbon curve and scale it down S and move the mouse :

Now all is about extruding the overall shape curve.
Select it, enter edit mode, select an extremity vertex (control point) and type E and move the mouse.

Alternatively, you can also extrude with LMB holding the Ctrl key simultaneously.

Eventually, you may need to subdivide some parts. Same can be done selecting two control points and with W then subdivide :

With these basic operations, you can 'draw' your shape.

Last operations to know :

You will need to twist your curve CtrlT then move the mouse:

And you will need to adjust the ribbon size AltS then move the mouse:


Some examples of shape key sculpting vs lattice? I understand the lattice modifier is for deforming complex objects and it's actually pretty amazing.  But the more I think about it, all the fine details can be done through sculpting shape keys.  Lattice seems to have static squares which you can scale infinitely to refine your detail, but I can't think of any reason to use it over just sculpting what I want in using shape keys.
My brain is probably not seeing the big picture here...  I'm mainly just focused on characters organic stuff.  Even if I wanted a bicep to expand, I can do it better with shape keys.

Shape keys and lattice are 2 completely different things in my opinion, generally you should think about shape keys (or bones) when you want to animate small details of your mesh, and Lattice (or Mesh Deform or Surface Deform modifiers) when you want to deform the whole mesh or a large part of your mesh.
Also, lattice is particular as it deforms only the part of the mesh that it contains, here is the kind of thing that you can do with Lattice that you couldn't do with shapekeys or Mesh Deform or Surface Deform:

Here is what it would give to have a boolean object that is latticed:


Splitting disconnected vertices in different objects I know I can use Ctrl+L to select vertices connected to a given one than P to separate selected vertices and move them in another object (as explained here for example).

But, is there a shortcut to do this automagically when there is like one hundred sub objects that I would like to separate ?

In edit mode select all (A), press P to separate and select "by loose parts".

Unconnected geometry will be separated into new objects.


How can I model indentations on a surface? I'm trying to learn blender, and for fun trying to make a model of a bottle. The bottle shape is no problem, but the bottle has a special pattern in its material that needs to be cut out from it. How can i do this? I tried many different ways but nothing worked very well. I've attached an image of bottle in Blender. The pattern I want to cut out is the photo I've used as background image.

The Blender file

The secret is to model the indentations first, then use a deformer to create the twist.

Start with a cylinder with 9 sides.  Bevel (Ctrl + B) the edges and add an edge loop top and bottom, this will be the lip of the indentation.
Select the sides that will be indented.  Use polygon inset tool (I) to make them inset and indented.

Add a Simple Deform modifier.  Adjust the angle to meet the reference image.

Add a Subdivision Surface modifier and preview the result.  Apply the deformation modifier.
Select top and bottom edge loops.  Use the LoopTools Circle tool (this requires the LoopTools addon).

Extrude (E) the top and bottom faces and model the rest of the bottle.


Grass Particle System I recently watched the grass essentials video from andrew price at blender guru and he said that it would be easier to use objects of grass in a particle system rather than strands. How would you get your object and put it in a particle system?

In the particles tab go down to the "Render" section.

Then Select the option "Group" and select the group you want to use.


How to simulate a dented surface for metal I'm trying to model a conquistador helmet for a game. But I ran into a problem since I am quite new to blender. My model is too smooth, I would like it to have a dented surface (see picture below).

(My render on the left, wanted effect on the right)

I have tried to mess around with displacement and a image texture, but I could not find a imagine with the wanted effect. Is there another type of texture I could use or perhaps another method?

(My attempt to add displacement marked in red)

Any help would be greatly appreciated

First of all you should mime the glossiness of the two helmets. By examining the spreading of light near the highlites you can notice how the object on the right has sharper reflections.

Build a simple material based on a glossy shader with low roughness lit by a nice HDRI iage.

In order to get make the object less smooth we should deform its surfaces. This can be done "physically" by sculpting ridge and vallys or "faked" by altering the normal vector of the faces for example by plugging a noise texture with appropriate scale in a bump node and then in the normal socket of the shader (or wih the displace method as you already introduced).

Each face reflects light toward the camera based on its orientation. If you bend the face's normals, they will start to reflect light the way it would look if the surface was truly deformed. By examining the edges, a viewerwill probably be able to discover the trick, but at a first glance should look good enough amd will help to kee your polycount low.

A second thing to notice is that the object on the right has some little scratches that yours is missing. One of the possible way to reproduce a similar effect could be to use a texture to drive the roughness of the smooth shader.

You could have used the displace/normal method also in this case: they are some kind of surface deformations too, but as the effects has a very small scale I find taking advantage of roughness variation more appropriate.

Final step is to balance the two effect in order to get the wanted result.


Add prefix to filename on "Save Blender File" I want a prefix added to the name of the .blend file when saved through the "Save" File Browser.
Generating the prefix and new filename is no problem, but actually using the new filename is what i need help with.
So, what i want, if possible, is to "hook" into the "Save Blender File" button (or similar) to change the name of the .blend file when it is saved.
I want this to be done through a python addon.

Saving the blend file is performed by the bpy.ops.wm.save_mainfile() operator. This operator accepts a filepath which makes it easy to save the current blend file using a new filename. A simple operator can be created that calculates the new filename and then passes that to the standard file save.

While there is no easy way to alter the file menu without altering blender's bundled scripts, we can add an item to the file menu and disable the existing shortcuts so that the custom save operator will be used.

Edit: I thought this would be more complete if the user can specify a python string that calculates the prefix instead of having to alter the script. I have also included a helper function to easily include a formatted timestamp with timestamp().strftime()

bl_info = {
    "name": "Save File Prefix",
    "author": "sambler",
    "version": (1,0),
    "blender": (2, 71, 0),
    "location": "File->Save Prefixed Blendfile",
    "description": "Add a prefix to the filename before saving.",
    "warning": "Runs user specified python code",
    "wiki_url": "https://github.com/sambler/addonsByMe/blob/master/file_prefix.py",
    "tracker_url": "https://github.com/sambler/addonsByMe/issues",
    "category": "System",
}

import bpy
import os
import time, datetime

class PrefixSavePreferences(bpy.types.AddonPreferences):
    bl_idname = __name__

    prefix = bpy.props.StringProperty(name="Prefix calculation",
                    description="Python string that calculates the file prefix.",
                    default="timestamp().strftime('%Y_%m_%d_%H_%M_%S') + '_'")

    def draw(self, context):
        layout = self.layout
        col = layout.column()

        row = col.row()
        row.prop(self,"prefix")

def timestamp():
    # convienience function that is available to the user in their calculations
    return datetime.datetime.fromtimestamp(time.time())

def fn_prefix(context):
    user_preferences = context.user_preferences
    addon_prefs = user_preferences.addons[__name__].preferences
    return eval(addon_prefs.prefix)

class PrefixFileSave(bpy.types.Operator):
    """Set a filename prefix before saving the file"""
    bl_idname = "wm.save_prefix"
    bl_label = "Save Prefixed Blendfile"

    def execute(self, context):
        outname = fn_prefix(context) + bpy.path.basename(bpy.data.filepath)
        outpath = os.path.dirname(bpy.path.abspath(bpy.data.filepath))
        print(os.path.join(outpath, outname))
        return bpy.ops.wm.save_mainfile(filepath=os.path.join(outpath, outname),
                    check_existing=True)

def menu_save_prefix(self, context):
    self.layout.operator(PrefixFileSave.bl_idname, text=PrefixFileSave.bl_label,
                icon="FILE_TICK")

def register():
    bpy.utils.register_module(__name__)

    # add the menuitem to the top of the file menu
    bpy.types.INFO_MT_file.prepend(menu_save_prefix)

    wm = bpy.context.window_manager
    win_keymaps = wm.keyconfigs.user.keymaps.get('Window')
    if win_keymaps:
        # disable standard save file keymaps
        for kmi in win_keymaps.keymap_items:
            if kmi.idname == 'wm.save_mainfile':
                kmi.active = False

        # add a keymap for our save operator
        kmi = win_keymaps.keymap_items.new(PrefixFileSave.bl_idname, 'S',
                    'PRESS', ctrl=True)

def unregister():

    wm = bpy.context.window_manager
    win_keymaps = wm.keyconfigs.user.keymaps.get('Window')
    if win_keymaps:
        for kmi in win_keymaps.keymap_items:
            # re-enable standard save file
            if kmi.idname == 'wm.save_mainfile':
                kmi.active = True
            if kmi.idname == PrefixFileSave.bl_idname:
                win_keymaps.keymap_items.remove(kmi)

    bpy.types.INFO_MT_file.remove(menu_save_prefix)

    bpy.utils.unregister_module(__name__)

if __name__ == "__main__":
    register()