text:
How to add palm leaves to animated sapling tree
I'm trying to use the Sapling add-on to create and animate a palm tree with a certain large palm leaf. Creating the base palm tree is pretty straightforward after using the downward curves for the main branches.
I thought I could use the branches as the larger leaf stems then have the individual leaves come off those branches/stems.  The problem is getting these specific palm leaves right.  I don't think I can use the Sapling add-on for the individual leaves because the leaves have to be offset from both sides of the branches (or leaf stems).  So I'm trying to model the larger palm leaf and add it to the animated tree using the existing armature for the branches.  But I don't know if I can add my larger leaves to the existing armature.
Any ideas would be hugely appreciated.  Spent hours on this already.
Many thanks!

Load a reference image of what you are trying to do with the leaf arrangement...  This is of interest to me, too...

By the way, the way we do this now is SpeedTree... but there must be a solution....

Thanks, @rcgauer.  The sapling add-on seems to have gotten me (almost) where I need to be as far as the trunk branch structure - including the animation.  Just would need to mess with the trunk shape.  I have not looked very closely at the SpeedTree product due to the price tag.  But if you look at the models, the coconut palm and date palm have the types of leaves I'm going for.  Just can't figure out how to get these with sapling.  Thanks for taking a look.

Here's what I've got from a bit of playing with the sapling addon. It's not too detailed but it accomplishes having the leaves on both sides of the branch. The key setting here is under the "leaves" settings, set the "Leaf Rotation" to 180 degrees. This makes every alternate leaf appear on the opposite side of the branch.


text:
How to make moving strip?
How do I animate a strip so that it looks like it's being drawn over time, as though it were produced by actual writing?
I can't find a direct way to make it. For now I am using a surrogate method - make an array of planes and add it to a curve path, then animate the array count.

I don't know if it will suit your needs, but you can take a look at the new animation tools with the grease pencil? Demo here: http://www.cgmeetup.net/home/blender-2-73-new-grease-pencil-tools/ and doc here: http://wiki.blender.org/index.php/Doc:2.6/Manual/3D_interaction/Sketching/Layers_and_Animation

You can use a curve to do this. in order to make it into a tube you need to set the fill to full and raise the bevel depth and resolution. You can then animate the start value to control the end of the strip. If you need to scale up or down the ends, select a point on you curve and use Alt-S.
To animate, the start value hover over the input box and it I to add a keyframe. The navigate to the other end of your animate, set the value down/up then hit I again to add another keyframe. Keyframes can be remved with Alt-I.

The green lines in this gif were created using this technique in blender
Single image with settings
Green squiggles file:

That is what I need, thank you very much! I want also to make strip that has not only round shape but square too.

If this helped you please mark it as accepted. Could you elaborate on what this square shape would looklike? Have you tried turning the bevel resolution to 0?

Imagine the strip (or belt - English is not my matherlanguige) that was broken. In place where it was broken should be square (or poligone).

Setting it to 0 should work, it will have four edges, you may need to set it to hard shading to make it appear square.

source: Stack Exchange

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/

sort: votes


text:
How to merge all identical materials into one?
I have made some trees to make a forest and each tree has its own file. Now I have appended them into one file and now I have like 40 unnecessary materials which are completely the same and each is assigned to a few objects, so that I would have to switch materials for about 200 objects to get rid of them. Is there some other way to merge the identical materials into a single material?

Select all the objects that share the same material. Using Select->Select Pattern may be a quick way to do that.
⎈ CtrlL -> Material will set the same material for each object.

authors: Артик Казорио

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


text:
How to make Sapling addon settings reappear?
The menu for settings disappears when I click on another menu. How do I make it visual again?
When modeling trees with the Sapling add-on, if I click Undo the settings disappear for the Sapling add-on.

This is standard behavior. You can not edit any settings after editing, moving, deselecting, etc. anything in the scene without the editing menu being removed.
More information

well cool and all but say we ctrl-Z, why is it still not showing up then????

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


text:
How can I customize the Render Button in the Render GUI to execute a custom script
I am trying to customize the blender GUI so that I can customize the Render button in the GUI to call a customer script as opposed to the default option.
I would like to know if there is a way to achieve the same and would appreciate if someone can point me to the pointers for the same.

The easiest way is to right click on the render button (or any UI item) and select Edit Source. You will see a message in the info header to 'See properties_render.py in the text editor'. Simply change one of your windows to a text editor and select the properties_render.py from the text block list. You will find the cursor located on the line used for the UI item you selected.
If you search the blender python api documentation for UILayout you will find the operator function used there takes the operator name as the first argument. So you would change "render.render" to the name of the operator you want to use.
Remember to save the edited text block back to the text file. Also this file will be replaced with each blender upgrade so creating an addon may be a wiser choice for something you plan to keep using.


text:
Emission Object is in front of every other object

Hello. I have 2 objects here, the dark cube is a diffuse black color, the white cube is an emission. I have these objects in different layers and have set the render layers up, so I can blur the white cube only.
I try to add these 2 render layers together and the cube is always in front of the black cube. I tried using the less than math node, but using it prevents me from blurring the emission cube.
I would love to know what I am doing wrong here. Any help would be greatly appreciated.

Can you show your node setup?

To help others I suggest you change your title to something more general such as .... Layers and Compositor Problem

Hi, yes I have been using the Alpha Over Node, but I am wondering why it is doing this now, when it has never done it before. It is very strange.

I can not add any more pictures, it keeps telling me that I do not have enough of something. Rather odd.

Please consider using the [alpha over node].
For transparency in Cycles render use Panel Film Transparent.

[ Alpha over node ] respects transparency alpha.  In your example opaque black cube would be opaque over all parts of the blurred white cube.
Alpha is transparency and its effects are only visible by compositing two or more layers.
In the image above the white emission cube in layer 2 is blurred.  The sphere and yellow emission cube are in layer 1.  Yellow emission is to increase legibility of explanation.
Two render layer specifications use different visual scene layers in the image below. (Layers and Scenes have some difficult terminology in Blender which could be improved)

3D Views with object visibility in layers in the image below.

Note the checkered background for transparency. Using [object index] is a complement or replacement to layers.


text:
Is it possible to enable render transparency for only certain renderlayers?
I am currently rendering a scene that because of polycount issues I have to render on three different renderlayers. However I would like to disable the render transparency for one of those renderlayers. Is this possible?

A possible way is to split objects into several scenes, and in those render layers select which scene it's added from. One scene will use Film > Transparent while another one will not.

You can do this by assigning objects into different layers and setting render setting to transparent in the Scene setup property page.

Like the "environment" setting?


text:
Unknown Syntax Error in Code
So, I am following a tutorial on CGCookie, and it is using Python code to create an audio visualizer in Blender. Now, I've always been a coding geek, but I don't actually know Python. I've taken a few shots at it but overall, I don't know Python, however, I can read and understand the code because I know basic programming concepts. Now, I'm following this tutorial as closely as I can (the tutorial does not provide code to copy and paste) and I am getting a syntax error. As far as I can tell, there is no syntax error. The line of code (specified by the error message) appears perfect. This line of code is supposed to set the 3D cursor to the active object's origin. Here's the catch: if I run that exact same line of code in the console, it executes just fine.
So here's the error message I get:
File "C:\Me\Blender\Blender Projects\audio visualisation.blend\AudioVisualizer", line 17
bpy.context.scene.cursor_location = bpy.context.active_object.location
   ^
SyntaxError: invalid syntax
location: <unknown location>:-1

It tells me to look in the console for error message, but the console doesn't output anything.
Here's my overall code:

Thanks!

EDIT: Alright. I've tried all the examples and all the procedures that have been suggested by you guys, but it keeps feeding me errors. According to the console, one of the problems it is spitting out is in C:\Program Files\Blender Foundation\Blender\2.74\scripts\modules\bpy\ops.py. This makes me think there is a bug in the API that is causing one of the many errors.
EDIT: Here are the error messages I get for my code.
Original Code:
Error:   File "C:\Gannon\Blender\Blender Projects\audio visualisation.blend\Audi
o Visualizer", line 35
    bpy.ops.graph.sound_bake(filepath="C:\Gannon\Blender\Sounds\Music\Batty McFa
dden.mp3", low=i*step high=i*step+step

                         ^
SyntaxError: invalid syntax

gandalf3's Code and zeffii's Code are essentially the same with alternative formatting which changes the line numbers where the error occurs.
Error: Unsupported audio format

Traceback (most recent call last):
  File "C:\Gannon\Blender\Blender Projects\audio visualisation.blend\Audio Visua
lizer", line 42, in <module>
  File "C:\Gannon\Blender\Blender Projects\audio visualisation.blend\Audio Visua
lizer", line 35, in spiral
  File "C:\Program Files\Blender Foundation\Blender\2.74\scripts\modules\bpy\ops
.py", line 189, in __call__
    ret = op_call(self.idname_py(), None, kw)
RuntimeError: Error: Unsupported audio format

@zeffii it really doesn't look any different. I've tried everything that you and gandalf3 has suggested, so that's basically what it looks like now.

@zeffii Right. I still get many error messages.

error messages? paste them or screenshot them .. or download / install a latest version of Blender from https://builder.blender.org/download/

@zeffii how do you copy error messages to your clipboard?

in windows, http://www.howtogeek.com/howto/windows-vista/copy-to-the-clipboard-from-the-windows-command-prompt/

@zeffii Done. I added the messages.

make sure you have that mp3 file

This looks like a path issue. I'll extend my answer with an example of how to test if your path to the music file is valid, (and therefore giving Blender's bake code a chance to do something with it)

You got pretty close TheMinecraftMan757, i've seen many people struggle with that tutorial over the last 3 or 4 years. I think even some of the function calls have been changed.
as Gandalf points out:

to scale_apply() on line 24 should be transform_apply(scale=True)

At the time the tutorial was written, the function call was scale_apply(), but it was changed to a more general apply function that can apply not just scale, but rotation and location. You would never have figured that out in a million years without a bit of googling or more familiarity with bpy.
here's my minimized interpretation of that code.
import bpy

rows = 5
columns = 5

def spiral(X, Y):
    scn = bpy.context.scene  # an alias, lets you use scn shorthand
    x = y = 0
    dx = 0
    dy = -1
    for i in range(max(X, Y)**2):
        if (-X/2 < x <= X/2) and (-Y/2 < y <= Y/2):
            bpy.ops.mesh.primitive_cube_add(location = (x, y, 1))
            obj = bpy.context.active_object

            scn.cursor_location = obj.location
            scn.cursor_location.z -= 1
            bpy.ops.object.origin_set(type="ORIGIN_CURSOR")
            obj.scale = (0.5, 0.5, 7)

            bpy.ops.object.transform_apply(scale=True)
            bpy.ops.anim.keyframe_insert_menu(type='Scaling')

            action = obj.animation_data.action
            action.fcurves[0].lock = True
            action.fcurves[1].lock = True

            bpy.context.area.type = 'GRAPH_EDITOR'

            step = 20000 / (rows * columns)
            fp = r"C:\Gannon\Blender\Sounds\Music\Batty McFadden.mp3"
            bpy.ops.graph.sound_bake(filepath=fp, low=i*step, high=i*step+step)
            action.fcurves[2].lock = True

        if x == y or (x < 0 and x == -y) or (x > 0 and x == 1-y):
            dx, dy = -dy, dx
        x, y = x+dx, y+dy

spiral(rows, columns)

If you don't set the path to a valid one, then you can get errors like
RuntimeError: Error: Unsupported audio format

remarks:

On windows use r'C:\your\file\destination.mp3', the r turns the quoted string that follows it into a raw string literal, this is perfect for filepaths.
On linux you should really know how to compose a path, but if you're new to it, it might be something like: '/homes/your_user_name/music/some_tune.mp3'
This code can take a long time to bake each graph. Even with a 5*5 grid, it will bake the entire graph 25 times. Here's a version which places a print statement just before it starts baking each iteration, you will need to have the terminal/cmd-prompt open before running the command.

a simple script to test your mp3 filepath, but it is really worth your time to read the python docs about paths
import os

# on windows, string prefix r is used to avoid the need for double backslashes
# filepath = 'C:\\Gannon\\Blender\\Sounds\\Music\\Batty McFadden.mp3'
filepath = r'C:\Gannon\Blender\Sounds\Music\Batty McFadden.mp3'

# on POSIX systems (linux, osx)
# filepath = '/home/zeffii/cookoo_22may_2011.mp3'

found = os.path.exists(filepath)
if found:
    print('yes, this file was found')
else:
    print('nope, the path does not exist')

Hey! It actually works! I used your testing script and found that it wouldn't accept the file path. I tried putting it in a completely different folder, and that actually did work! I am kind of wondering if the original file location was somehow restricted. I don't know. Anyway, you fixed it! Thank you @zeffii!

it's OK, paths have tripped up many coders. onwards!

Oftentimes mysterious syntax errors result from something above where the actual error is raised. In this case the syntax error in question is caused by a missing paren on the line above:

In addition to this missing paren you have a few other typos:

+ instead of _ on line 22

scale_apply() on line 24 should be transform_apply(scale=True).

Missing a comma and closing paren on line 35

Here's the fixed code:
import bpy

rows = 5
columns = 5

r = 0
c = 0

def spiral(X, Y):
    x = y = 0
    dx = 0
    dy = -1
    for i in range(max(X, Y)**2):
        if (-X/2 < x <= X/2) and (-Y/2 < y <= Y/2):
            bpy.ops.mesh.primitive_cube_add(location = (x, y, 1))
            bpy.context.scene.cursor_location = bpy.context.active_object.location
            bpy.context.scene.cursor_location.z -= 1
            bpy.ops.object.origin_set(type="ORIGIN_CURSOR")

            bpy.context.active_object.scale.x = 0.5
            bpy.context.active_object.scale.y = 0.5
            bpy.context.active_object.scale.z = 7
            bpy.ops.object.transform_apply(scale=True)

            bpy.ops.anim.keyframe_insert_menu(type='Scaling')

            bpy.context.active_object.animation_data.action.fcurves[0].lock = True

            bpy.context.active_object.animation_data.action.fcurves[1].lock = True

            bpy.context.area.type = 'GRAPH_EDITOR'

            step = 20000/ (rows*columns)
            bpy.ops.graph.sound_bake(filepath="C:\Gannon\Blender\Sounds\Music\Batty McFadden.mp3", low=i*step, high=i*step+step)
            bpy.context.active_object.animation_data.action.fcurves[2].lock = True

        if x == y or (x < 0 and x == -y) or (x > 0 and x == 1-y):
            dx, dy = -dy, dx
        x, y = x+dx, y+dy

spiral(rows, columns)

that's a valid filepath on windows??

@zeffii What's wrong with it? It looks alright to me, but I don't know all the nuances of windows file paths. I'm on linux, so I can't test it.. (works fine when I point it at a sound file here though)

using r"c:\..\...\...\" is better or forward slashes, which are now universal

interesting if it does work :)

@zeffii Hm.. Is the drive letter case sensitive? I always thought they were upper case.. (and what's the r for?)

Thanks! There is, however, one more problem. It still won't run. Have you tested it with Blender 2.74? Do you have Windows 8 like I do? Blender won't define what the problem is or anything, so can anybody revise it again?

I've tested it here on linux (blender 2.74) and it works fine. Perhaps it's a problem with the path as @zeffii suggests? Try looking in the console (info panel > window > show console) to see if there is an error message  there.

i meant r"C:\...\...\..." sorry.  the r makes it a raw string literal https://docs.python.org/3.4/reference/lexical_analysis.html#string-and-bytes-literals

the drive letter is not case sensitive for windows.  Most console stuff isn't, passwords are the only exception that I'm aware of.


text:
How do I randomize the movement of trees made with the sapling generator?
I've made a couple trees/bushes with the Sapling add-on and then distributed them over a landscape with a hair particle system. The original trees have a "swaying in the wind" animation and when they get duplicated through the particle system, although the size and rotation of the trees is randomized, their animation remains fairly homogenous: they all sway in the same directions at the same rate.
Is there a way to randomize this through the particle system, or do I need to make multiple source trees with different animations attached to them?
I still want them to look like they are being affected by the same environment/wind but as it is now it's too synchronized. I've already given the different tree types and bushes different wind speeds and amounts of "gust variation" through the sapling generator options, but this doesn't seem to be effective enough.

If you need the forest to look more realistic, you would need more animations! One animation for all the trees is simply not enough.
My suggestions:

Add at least 3-4 different animations.
Make trees swap their animations randomly (e.g. tree1 runs animation1 then animation3...)
Don't randomise the rotation because that would look fake (wind blows generally in one direction)
Also be careful with the different wind speed as if you overdo this you might get unrealistic results.
You can simulate the wind 'gust' by starting the animations on all trees (seed points) which are at a certain position (say in X) and delay the animations of the other trees based on their Y position.
To make this even more effective you can actually simulate the wind by creating a huge box or a sphere(s) and animating them, passing through the forest in a certain way. This would be a non-renderable object which would trigger the wind animations on your trees. This could be even further enhanced if you increase the wind speed based on the proximity of the tree to the sphere centre, for example.
Also don't forget that even if you nail the whole wind animation, if you only have one tree model (despite different scale/rotation), it just wont work. You need more variation, only then you can play with randomness.

Animate your tree using shape keys. Remember that the verts move more or less straight to the target so you may have to do some tweaking. Doesn't take a lot of movement unless your wind is very strong. Set the minimum to -1 to get a full range. Once your shape key is made, set a key at mid position. Open your graph editor and with the shape key selected apply noise to it. Adjust the wave length to slow it down and adjust the intensity so it doesn't go beyond -1 or +1. Apply different shape keys for forward/backward and left/right with a different noise modifier for each that will give you a random looking movement. They still will all move the same unless you duplicate the tree and change the paramenters. The more trees you have the less they all appear to move together.

authors: Андрей Крючков


text:
Scripting help for Audio Visualizer Tutorial
So I was watching a tutorial and following along with how to make this audio visualizer:
http://cgcookie.com/archive/building-an-audio-visualizer-in-python/
This is what the portion of the script in the video that I am having problems with looks like. It's on line 32:

This is my entire script so far (Up to the point in the video shown in the picture):
import bpy

rows = 5
columns = 5

r = 0
c = 0

for i in range(0, rows*columns):
    if c == columns:
        r += 1
        c = 0

bpy.ops.mesh.primitive_cube_add(location =(r*2, c*2, 0))
bpy.context.scene.cursor_location = bpy.context.active_object.location
bpy.context.scene.cursor_location.z -= 1
bpy.ops.object.origin_set(type='ORIGIN_CURSOR')
####
bpy.context.active_object.scale.x = 0.5
bpy.context.active_object.scale.y = 0.5
bpy.context.active_object.scale.z = 5
bpy.ops.object.transform_apply(scale=True)

bpy.ops.anim.keyframe_insert_menu(type ='Scaling')
bpy.context.active_object.animation_data.action.fcurves[0],lock = true
bpy.context.active_object.animation_data.action.fcurves[1],lock = true

bpy.context.area.type = 'GRAPH_EDITOR'

step = 20000/ (rows*columns)
bpy.ops.graph.sound_bake(filepath="/Users/USER/Desktop/14 Federation.m4a", low=i*step, high=i*step + step)

bpy.context.active_object.animation_data.action.fcurves[2],lock = true

c += 1

I can see that in the video the part with step = 20000 and the part with bpy.ops.graph.sound_bake(...) are on the same line, but when I do that, it gives me syntax errors.
As of now, this script tells me that it has failed and then tells me to look in the python console. In addition, it only creates one of the cubes that the script is supposed to make a 5x5 grid of. It also unlocks all of the scale parameters and changes nothing for the graph editor for the one cube that it creates.
Strangely enough, removing the entire portion starting with bpy.context.area.type = 'GRAPH_EDITOR' to bpy.context.active_object.animation_data... causes the full grid of 25 cubes to appear.

it's either the formatting of your post or the script is broken / incomplete? The for loop does nothing as it is, shouldn't all subsequent lines be indented?

You can find several answers with complete code for this visualizer at http://blender.stackexchange.com/questions/30751/unknown-syntax-error-in-code with further explanations about API changes that broke the original tutorial code.

It is only creating one cube because your for loop is wrong.  In python the indentation is very important.  Note that in the code below, all functions for object creation have been indented to become part of the for loop, so that it is run 25 times, rather than once.
for i in range(0, rows*columns):
    if c == columns:
        r += 1
        c = 0

    bpy.ops.mesh.primitive_cube_add(location =(r*2, c*2, 0))
    c += 1
    bpy.context.scene.cursor_location = bpy.context.active_object.location
    bpy.context.scene.cursor_location.z -= 1
    bpy.ops.object.origin_set(type='ORIGIN_CURSOR')
####
    bpy.context.active_object.scale.x = 0.5
    bpy.context.active_object.scale.y = 0.5
    bpy.context.active_object.scale.z = 5
    bpy.ops.object.transform_apply(scale=True)

    bpy.ops.anim.keyframe_insert_menu(type ='Scaling')
    bpy.context.active_object.animation_data.action.fcurves[0].lock = True
    bpy.context.active_object.animation_data.action.fcurves[1].lock = True

The other errors were since you used bpy.context.active_object.animation_data.action.fcurves[0],lock = True instead of bpy.context.active_object.animation_data.action.fcurves[0].lock = True.  That should be it, just pay very close attention to detail when copying code.  It's helpful if you can find tutorials that include working code, and then modify it yourself, that way you know what changes break it.

Here's a full code sample that should work. It uses the spiral iteration technique in the tutorial.
import bpy

rows = 3
columns = 3

def spiral(X, Y):
    scn = bpy.context.scene
    x = y = 0
    dx = 0
    dy = -1
    for i in range(max(X, Y)**2):
        if (-X/2 < x <= X/2) and (-Y/2 < y <= Y/2):
            bpy.ops.mesh.primitive_cube_add(location = (x, y, 1))
            obj = bpy.context.active_object

            scn.cursor_location = obj.location
            scn.cursor_location.z -= 1
            bpy.ops.object.origin_set(type="ORIGIN_CURSOR")
            obj.scale = (0.5, 0.5, 7)

            bpy.ops.object.transform_apply(scale=True)
            bpy.ops.anim.keyframe_insert_menu(type='Scaling')

            action = obj.animation_data.action
            action.fcurves[0].lock = True
            action.fcurves[1].lock = True

            bpy.context.area.type = 'GRAPH_EDITOR'

            step = 20000 / (rows * columns)
            fp = r"C:\Folder\Anotherfolder\Cool song.mp3"
            bpy.ops.graph.sound_bake(filepath=fp, low=i*step, high=i*step+step)
            action.fcurves[2].lock = True

        if x == y or (x < 0 and x == -y) or (x > 0 and x == 1-y):
            dx, dy = -dy, dx
        x, y = x+dx, y+dy

spiral(rows, columns)

I hope that helps!


text:
How do I import a custom icon set in the theme options?
I'm trying to load a custom icon set, however Blender will not load it despite the fact that it's a modified version of the original SVG.

See related. Can I use a custom Splash screen?

Currently, you can't.
In 2.67 there is a button in the theme preferences, but since this is non-functional its been removed for 2.68.
Note that you can of course build your own blender from source with modified icons and fonts but this is outside the scope of stack-exchange.

Agreed. At most OP can refer to Can I use a custom Splash screen? or How to build and submit Mac builds to Graphicall?


text:
Realistic aerodynamic simulation in Blender
Is it possible to use Blender to simulate realistic wind forces that take into account the aerodynamic properties of objects in the model?
My use case: I modeled a windmill and want to use Blender to simulate that windmill rotating in the wind, taking into account the shape of each of the blades of the windmill, etc.
I can also see this being useful for a number of other cases: flags blowing in the wind, tumbleweed or trash blowing across the ground, trees bending in the wind, etc.
Can any of Blender's physics simulation engines (either built-in or from addons) handle this?

https://www.blender.org/manual/physics/force_fields.html

If you're using Cycles or Blender Render, you can set your scene up with Wind Force Fields. Each object that you want affected must have appropriate physics set up, the extent of that conversation being too long to have here. In short, your verdant growth and flags would use cloth simulation and your wind mill would have to use rigid body simulation. It is best read about at the link I provided.

I found this  on the manual, https://www.blender.org/manual/physics/soft_body/exterior_forces.html#aerodynamics but applies to soft bodies..? maybe if your mill blades sails can be done as softbodies..?
But realistic aerodynamic is really though, i think, there's turbulence also to be taken into account...

If you're using the BGE, you can easily simulate cloth by subidividing your target cloth objects and using softbody physics. Play with the settings for optimal effect, but I set my margin to .03, iterations to 5 and threshold to 0.
For your windmill in the BGE, you'll most likely rely on python. You could set the force of your wind to be applied to your cloth objects in script form, and use this same value to apply rotation to windmill screws. Force Field physics utilizes the particle system, which doesn't seem to have as much support in the BGE as Render/Cycles.

For this please use Houdini, it can simulate air-fields. Blender's simulation is not realistic by any means and it's all fake just for the looks. Air-fields are not supported, force-fields won't take airflow into account. If you'd like physically correct data you would have to use very expensive dedicated software, not even Houdini will help you.

Related: http://blender.stackexchange.com/q/1970/599

Also somewhat related: http://blender.stackexchange.com/q/5577/599


text:
How to align multiple wave textures?
When creating wood textures in Blender, I often use the Cycles 'Wave' procedural texture (the equivalent of the Blender-Internal 'Wood' texture). I can use it to create what appears to be very realistic wood grain.
However, I run into a problem whenever I'm modeling wood blocks with sharply cut edges. Real wood would have a different cross-sectional type of grain on each side, depending on how it was cut (for example, in the image below, one side would have a 'ring' structured texture, and the other two would each have a different 'band' texture). Moreover, if you look at any one of the individual dark bands, you'll see that they 'align' with each other across the three faces.

Is it possible to make three different procedural textures that align with each other in this way? If that isn't possible, is there any way to produce a similar effect using other techniques?

can you provide a sample picture of real wood which displays the output you are looking for? I don't understand "real wood would have a different cross-sectional type of grain on each side". The wave procedural texture is very much like real wood grain, it just lacks the "knots" often present in real wood. To control the grain, you need to control the direction of the wave.

thank you very much ! it helps a lot

A very flexible way to make the texture is to make it from scratch with the nodes, not relying on the built-in, a bit limited wave texture. Using some math nodes and adjusting the value results in a pretty nice wood texture.

Here the two vector inputs define a line that passes through both (the core of the three), and the distance from that to the object surface is calculated inside the distance node.

The surface positions are distorted a bit by adding a bit of noise to them, the distance calculation is done per the equation here.
Using modulo makes the distance from the surface to the line a looping range of values from 0 to the distance between the waves in the wood. Multiplying that by the inverse of the distance brings the range to 0 - 1, which can then be mapped into a nice gradient using a map range node. That can be used to multiply or mix the color value to achieve the final result.
See also:

http://www.minimaexpresion.es/?p=690&lang=en
http://materialw.wordpress.com/materials/wood-material/
http://blenderartists.org/forum/showthread.php?246113-A-fine-procedural-wood-material-for-Cycles
http://shiny-dynamics.blogspot.fr/2012/04/wood-texture-for-blender.html
http://en.wikibooks.org/wiki/Blender_3D:_Noob_to_Pro/Procedural_Textures
http://wiki.blender.org/index.php/Doc:2.6/Manual/Textures/Types/Procedural/Wood
http://www.blendswap.com/blends/view/52626 (mirror of previous link)

In order to make this practically useful, this needs to be changed to use object-space positions to define the core line, so the wood-core-lines don't move around when the object is translated or rotated. This can be done by computing the distance to "texture coordinate->object" instead of geometry->position

If you can use generated coordinates, there shouldn't be a need for multiple textures. Just adjust the mapping to place and distort the grain to your liking.

I know this is an old question, but it's very simple to solve.  The wave texture is taking an input vector that uses all three axes (X, Y, and Z).  A sphere is basically x, y, and z, equally in all directions.  If you eliminate the Z axis, it becomes a cylinder because it's just x and y along a constant z.  If that doesn't make sense, here's a super simple node network that just removes Z, and you'll see it gets you on your way to what you want.

Play with the colors and distortion values, as well as the scaling coordinates, and you should arrive at a decent basic wood.
You probably want to use Object coordinates rather than Generated, because Object coordinates make the shader as if your objects are carved from a solid piece.  Generated coordinates are like painting on the surface.
If you want to dive into an advanced network of nodes for wood, I have several blog posts that go into great detail of how I create a realistic wood shader: my blog


text:
Ctrl+A in rigging?
I am currently in pose mode trying to fix an issue, but something just made me curious: What does CtrlA do in pose mode? I have the following screenshot:

What does each of these options do? Any help is appreciated, thanks!

I mainly want to know what the second one does, I sort of know what the first one does but im not sure.

The second option will apply the current transformations after all constraints have acted upon the bone (ie IK constraint, limit rotations, track to, etc). This can be a way of "applying" bone constraints.
I'm fairly certain the bone will remain as is until you move keyframes or refresh the screen. If you apply the keyframe the constraints probably will reactivate so it may produce undesired behaviour.

authors: Владимир Тим


text:
Light spectrum dispersion effect in Blender?
I'm trying to achieve the effect where a beam of light sent through a prism or other refractive object, separates out into the light spectrum. (See image below)

This effect is especially useful to have when modeling gemstones, since the 'sparkle' of colors produced by this effect adds a lot of realism to the model.
It does not seem possible to get Cycles to produce this effect, since Cycles handles each ray of light as only a single, one-colored ray. Is there any way to coax Cycles (or any other render engine) into treating light as a full spectrum? Is this kind of treatment of light even possible in Blender?

I was about to ask this question myself, after looking all over for good techniques to get this effect.. :D

There's a new Add-on "Prism" which should help you achieve exactly this effect.

It is fake-able to some extent in cycles, see some of these results:
http://www.blendernation.com/2012/04/05/cycles-diamond-dispersion/
http://www.blendernation.com/2012/09/04/cycles-dispersion-glass-shader/
One technique I know of is to use multiple Glass shaders with different IOR values
A quick setup:

Low sample result:

(Not that great, but the closest method I know of..)
Luxrender is an open source unbiased bi-directional rendering engine with blender integration (and GPU rendering support via OpenCL) and is capable of this.
Some examples:
http://mitsuma.deviantart.com/art/LuxRender-Prism-198927185
https://www.youtube.com/watch?feature=player_detailpage&v=kIX5WL07Uss#t=15s
Luxrender (technically SmallLuxGPU, an early version of luxrender with GPU support)
https://www.youtube.com/watch?feature=player_detailpage&v=jk-N4f9ze4k#t=82s
Yafaray is another open source render engine with blender integration that supports both biased and unbiased techniques, and also seems to handle this well.
http://www.youtube.com/watch?v=RVHYMq8NEEs

Just a note, since Cycles' caustics are still not very good, if you use that Cycles material setup in a low-light setting you end up needing about 10,000 samples to see anything reasonable. I ended up going with Luxrender for that reason, and I've gotten great results, thank you!

LuxRender and its associated website has since moved to https://luxcorerender.org/ and the old links in this post now lead to a random shop.

@ch4rl1e97 thanks for the heads up!

Do you suggest any lights paths/rendering configuration to avoid noise? With high value of max bounces and 1000 samples is still noisy.

@Iván unfortunately this is just an uphill battle for pure-forward path tracing, leaning on denoising and trying to make light sources larger are probably the two most fruitful things, outside of using an engine that supports bidirectional or metropolis sampling (e.g. luxcorerender). noisy at 1000 samples doesn't surprise me, in my experiments with caustics in cycles i usually have to do closer to 10000

Cycles only shoots rays from the camera:

(source: blender.org)
For dispersion, support for bidirectional path tracing needs to be added. This is currently considered a low priority. There has been a community effort to get an additional developer to implement it.

Having myself written a unidirectional forward pathtracer supporting dispersion, I can say that requiring BDPT is incorrect.

I know this is old, but there's now a White Noise Texture added with 2.81. It generates a random value based on the input. So if you put something like Geometry > Position or a texture coordinate (as long as it's different depending on where the ray lands on it) it will be noisy at first (some pixels white/some black/some in between) because each iteration it actually samples ramdom trajectory within each pixel's cell.
All this is to say, you can actually use the white noise to randomize the IOR and the color. And because it's fully deterministic PRNG (same input = same output), if it generates 0.68274, it will use that number for the IOR & the hue of the color, effectively mimicking the property of certain wavelength refracted at certain degrees. Just make sure it's the same white noise node to randomize both.
All that bidirectional path tracing does is seemingly just randomize the wavelength and use that to determine the refraction IOR. It wasn't possible to randomize something per ray before, but now it actually is and you can, in fact, approximate dispersion very well in RGB. Bidirectional would just be slightly more accurate-looking.

I'm curious about your method, and I'd like to see this answer developed some more if you have the time. :)

This sounds interesting, but from what I'm reading in the answer I have no idea how to setup a material for this method...

I know this is a bit late, but I've finally elaborated on this here:

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


text:
How to add a new Text Editor template?
In Blender's built-in Text Editor, there's a Templates menu at the bottom with a bunch of pre-built templates for scripting addons. However, I have created a few new templates myself that I use frequently. Is there any way for me to add my templates to this menu?

In [version_number]/scripts subfolder of your Blender installation, or in any additional path(s) for scripts you've set in User Preferences, there's a folder templates_py (and one for osl too). Just put the templates there; in the menu, each _ in the file name will be converted into a space and each beginning letter of a word capitalized.

Very trivial note ;), the beginning letter gets uppercased and also the first letter that comes after a number.

Ha! Never realized the number-prefix bits :D

The Templates > Python menu item is getting quite long now.
1. x_templates
repository link
Here's an add-on that adds an extra sub-menu called x_templates to the Templates list, and dynamically creates sub-sub-menus

To make menu items all you have to do is add folders and files into the add-on's folder. The add-on does the rest.

Each of these folders (except the __pycache__ folder) contains some number of .py files.

2. Using self.path_menu
Add your own folder along side the existing folders.

self.path_menu(fullpath, "text.open", {"internal: True})
like this
bl_info = {
    "name": "Extra Templates",
    "author": "you",
    "version": (0, 1),
    "blender": (2, 7, 6),
    "category": "Text Editor"
}

import bpy

class TEXT_MT_templates_my_py(bpy.types.Menu):
    bl_label = "My Python"
    bl_idname = "OBJECT_MT_custom_py_menu"

    def draw(self, context):
        self.path_menu(
            bpy.utils.script_paths("templates_my_py"),
            "text.open",
            {"internal": True},
        )

def draw_item(self, context):
    layout = self.layout
    layout.menu(TEXT_MT_templates_my_py.bl_idname)

def register():
    bpy.utils.register_module(__name__)
    bpy.types.TEXT_MT_templates.append(draw_item)

def unregister():
    bpy.utils.unregister_module(__name__)
    bpy.types.TEXT_MT_templates.remove(draw_item)

if __name__ == "__main__":
    register()


text:
Is the Blender GUI package available for other programs?
I really love the look of Blender's built-in GUI, and would potentially like to use these tools in some of my other Python applications. As I understand it, Blender created all of these tools from scratch, instead of inheriting them from one of the other standard GUI packages (wxPython, Tkinter, qt, etc).
Do these tools exist as a stand-alone package that I could use, either in addition to or instead of other packages (preferably something as simple as import blender_gui)?
For example, how could I use Blender's Node Editor setup in another Python application?

Short answer: no
...at least nobody has split off Blender's user interface from the application so that it can be used separately, and doing this isn't trivial.

Even if such a task were undertaken, keeping the code-bases in sync would be a challenge, so I think there is not much interest to do this. Besides, there are many UI toolkits out there.
There is GHOST (General Handy Operating System Toolkit), which can be used outside of Blender, but it's very low level, only providing window access, mouse, keyboard, ndof and tablet events from X11/MS-Windows/OS X.
It doesn't actually draw anything; buttons or text, for example, are handled by Blender's own code. So likely GHOST isn't what you want.
Rather then using GHOST you're better off using a general purpose library such as SDL, Allegro, GLFW, or SFML. Some of these libraries have Python wrappers; for example, PyGame is a popular SDL wrapper.
And, as for UI toolkits, there are too many to mention here; there are enough resources online.
See: Q What are the best cross platform widget toolkits?

On the other hand, nothing is stopping your from making a fork of Blenders UI for your own purposes, its just likely you'll end up having to spend time refactoring code out for your own use where you might better spend time working on the application its self.

Thanks for the answer! I'm a pretty heavy user of wxPython for application GUI, I was just wondering if I could port over some of Blender's features easily (especially the node editor). It appears the answer is sadly no.

No. You cannot use Blender's GUI package in other programs outside of Blender.
Blender Graphical User Interface package is solely designed to be used with Blender on various platforms. Blender also has a custom window manager. And the UI widgets in Blender are tightly coupled with Blender's Data API (RNA/ID properties)
Most other user interface toolkits have their own runtime and are created for generic use, hence contain lots of functionality that either conflicts with Blender Design Goals, or adds unnecessary size to Blender package (hence increasing download size)
Some of the design goals of Blender user interface as stated in the Wiki

The Blender user interface is based on 3 main principles:

Non Overlapping: The UI permits you to view all relevant options and tools at a glance without pushing or dragging windows around.
Non Blocking: Tools and interface options do not block the user from any other parts of Blender. Blender doesn't pop up requesters that require the user to fill in data before things execute.
Non Modal: User input should remain as consistent and predictable as possible without changing commonly used methods (mouse, keyboard) on the fly.

However, Blender 2.5 permits multiple windows for multi-screen setup. It is an exception to the Non overlapping rule.

As satishgoda says, No. Blender uses its own windowing wrapper to provide OpenGL window access - called GHOST. I won't get into too much detail as satishgoda's answer pretty much sums it up.
However, while it might not be exactly what you have in mind, you can definitely use this toolkit to draw your own shapes/interfaces as Blender's entire interface is drawn in OpenGL. (src)


text:
Objects other than leaves with Sapling addon?
The Sapling addon does an excellent job of modeling the shape of the trunk, branches, and leaves of a variety of trees, and can be used to quickly produce realistic trees in my models. However, real trees often also have flowers, berries, pine cones, buds, etc which I would like to include sometimes.
Is it possible to add these objects using the Sapling addon? If not, would it be possible to configure a particle system to add these objects onto the tree-object created by the addon?

How about randomly selecting some of the leaves, separating them and scaling them to match the size of whatever object?

@CharlesL With the Sapling addon, the leaves aren't individually selectable (the leaves are all a single object, and the trunk/branches is a single object--this speeds up modeling/rendering times immensely)

you could do it in edit mode after generating the tree.

1) When creating the tree with Sapling, choose 'Rectanglular' for the leaves' shape because it will allow you to create a UV map. Also, make sure to select the appropriate leaves distribution.

2) Select your leaves and enter Edit mode.
3) Open an Image/UV Editor window and Activate the "keep UV and Edit mode in sync" option in the UV editor window
4) In the 3D View, select 2 vertices that are on the branch side, they will appear orange in the UV Editor.
5) In UV Window, with the box selection, select all those "branch vertices" which are actually above each other.

7) Subdivide once, you get the vertices that are directly on the branches, select them as well in UV Window and separate with P in the 3D View.

8) A new object is created with only vertices, put a particle system on it with emission per verts. Done :)

Really useful to replace default leaves with nice 3D leaves as well :)
An example. I made the new leaves and fruit using that method (The branches are the default one, ugly but it's not the point) :

Really good idea! +1 from me.

Someone down-voted. Could he be constructive and say why ? It's the method all professional I know use, so it maybe good to learn them a better way of doing it :)

There really isn't a reason. Your answer is great. Don't let it get to you :)

Or you may try to simply put a particle system onto
the leaves without any hassle, when you need only random
fruits on it, but no precise control over their position.
Emit from faces with low amont, experiment with velocity
and rotation, render with object or group. For still
particel systems I usually use - 1 start 1 end.
See the example. I did not take the time to make
it photorealistic. It came to my mind, you may
control the fruits position with vertex groups.

Make sapling - select leaves in object mode
Select vertices/faces in edit mode- assign to vertex group
Create particle system - hair with the object/group you like - use selected vertices for density (under the vertex group tab)

This way you have full control over the placement of the objects (like blooms on the sunny side of trees) or the apples to the south.

Create your tree with rectangular faces, parent your object to the leaves object and enable Duplication Faces:

Perhaps someone could elaborate on a way to instance a group of objects instead of just a single one?


text:
How can I convert a hair-particle system into 3D, editable objects?
Is it possible to 'apply' a particle system so that it becomes workable 3d objects instead of being hair or emitter objects? If that's possible, then I should hypothetically be able to apply another hair-particle system to those objects, right?
I want to use this to make realistic feathers, if possible. The first hair system would be the shafts of the feathers, and the second would be the barbs.

why apply? just add another layer of particles.

I like the question, but maybe we could find a better use case?

@iKlsR How do you apply a second layer of particles? Is there any way you can do it that lets you comb, etc the second layer without at the same time adjusting the positioning of the first layer?

@Gwenn I don't work that much with particles but if you click the + and add a particle system to a mesh, you can click it again and add another one on the same mesh.

@iKlsR As far as I can tell, that still only adds another particle system to the original mesh, not the existing particle system. I'm trying to create a branching structure of sorts, which requires the new particles to come off of the first ones.

@Gwenn, I only fully understood the question after I had edited it (the title and content were off), you will have to work more with the answer below.

In the modifier panel click the convert button.

That should do the trick.
Two things to note:

If you're using an object, the objects will be linked when converted.
The original emitter will continue to emit particles. Make sure to either delete the emitter, or delete the particle system.

By the way, CGCookie has a tutorial (archive) on creating a feather if you're interested.

This alone doesn't quite solve the problem. It works to apply the modifier system, but still treats the entire particle system as a single object. However, the system can be separated into individual objects using the methods outlined in http://blender.stackexchange.com/questions/109/array-modifier-to-create-indivudally-manipulatable-objects. Thanks!

I might be running a newer version of Blender (2.77) but I don't have the problem @Gwenn described. When I hit convert it converts every object into an individual object in the scene. Also the original emitter is automatically deleted so I didn't have to go back and do that either.

You could also use Make Duplicates Real (in blender 2.8: Make Instances Real) Shift-Ctrl-A accessible in Object Menu → Apply (or Ctrl-A)
This way I created a forest from a single tree with an hair particle system.

When I was trying to create hair from particles, this is what I did:
First, create the scalp by selecting faces on a 3D character's head.  Select Shift+D to Duplicate those faces, then type "P" and Click on "Selection" to separate those duped faces to make its own object.
Then (I'm think this was an addon) click on Object>QUick Effects>Quick Fur.  From here, you can look at the Particles tab (wherever you have it set up in the interface), and select the number of parent hairs, their length, and how many children you want those parent hairs to spawn (ok...that sounds disturbing.)  From here, once the hairs become visible, you can switch from Object Mode to Particle Mode, and style your hair particles as you wish.
When happy with final style, go back to Object Mode, click on the Modifiers (Wrench) tab, and select "Convert".  This will convert the particles of hair into a mesh...but it doesn't stop there.  You actually have to convert the "mesh" into "Curves".  Object>Convert to>Curves From Mesh/Text.   Once this is done, deselect everything, and add a bezier circle (Add>Curve>Bezier Circle) to the canvas. (Be sure to translate the circle away from your build so that you can easily select and manipulate it).  Switch to the Curves Tab.  Select your hair, and then click on the eye-dropper in the Bevel Object button.  This will now add geometry to your hair curves, and those curves are influenced by the size and shape of the Bezier Circle.  Reduce the Bezier circle  so that the individual hairs reduce in witdh to something to your liking.  Now, while still in Edit Mode, type A to select all the hair curves, then type P and click on Separate.  This will duplicate those curves, but those duplications will now be separated from the Scalp Mesh.  The hair sources that are still on the Scalp Mesh are STILL in Particle mode.  You can then delete the Scalp Mesh, (or move it to another layer) leaving only the hair curves.
Once that is done, Select Object>Convert To>Mesh from Curve/Meta/Surf/Text.  Now your hair has become an mesh that you can export as a .obj.   HEADS UP (no pun intended):  This is extremely dense in terms of face count, and I do believe that when you do the conversion from Curves to Mesh, it does so in quads...so this may be about as low poly as you can get. You can use the Decimate modifier to try and reduce the face count, but there will be a lower limit, so the reduction might not be so much as to greatly effect a reduction in memory.  Caveat Emptor!
I hope this helps. :)


text:
How to make a model cast shadows onto the world texture/background?
In most of my models, I usually end up setting a world background using an HDRI image of some kind or another. This has always been really useful for lighting in general or as a background for my final render.
But what if I want my model to look like it is interacting or touching part of the background? For example, in the image below that I found, the modeled objects look like they're part of the scene, and even appear to cast shadows on the ground. How can I do this?

Can you accept the cycles answer instead of my BI one so it gets seen first, thanks.

One quick way to achieve this using Blender Internal is to select the plane and add a new material, in the material settings under shadow, enable Shadows Only.

Next, you can optionally enable transparency, use Z Transparency and use the alpha slider to control the strength/darkness of the shadow.

To further enhance this and add to the realism, you can enable Ambient Occlusion and use a blend sky (for simple renders). It is also worth noting that the shadow you get is dependent on the type of lamp and world settings you use in some cases, in the image below I am using a sun lamp with ray shadow enabled and I also have Environment lighting turned on, this softens the shadow and its harder to control but gives a nicer subtle effect.

Here I am using a sun lamp and a point lamp with Environment lighting off, with this setup, I can easier adjust the opacity of the shadow with the transparency setting.

Finally, in a case like you describe above, just render the scene without the sky (untick sky under the scene tab), align the camera as best as you can to the angle of the background, render and use an Alpha Over node to join the render and the background together. Here is a quick example I did in a few minutes.

With HDR lighting and some tweaking, this can look really good. It's a bit tricky depending on how you want to use it and at times it will take a good amount of tweaking to get it to look 'right' but this is a sure way to go about it, the ground plane still catches the shadow but it is invisible.

iKlsR is right. Shadow-only textures will do the trick. Adding a floor will do wonders. If you want shadows to have additional play with other things in the scene -- e.g. people and buildings -- then camera mapping will go a long way. Andrew Price explains it flawlessly in his Camera Mapping tutorial and again in Part 2 (an updated one).

And shadow only textures simply can't be done (as of 2.77) in cycles. That means cycles is... Better, right..?

@philipyassin huh?

@iKlsR http://blender.stackexchange.com/questions/58342/3d-scene-in-vse-hide-an-object-keeping-the-shadow

Updated link to version 2 of the camera mapping tutorial: https://www.blenderguru.com/tutorials/camera-mapping-tutorial-v2

CYCLES ENGINE
Shadow Catcher
Starting from version 2.79 any mesh object can be set as Shadow Catcher.
Select object (like a Plane) and check this option.

2.79 located in Properties Editor > Object > Cycles Settings
2.8+ located in  Properties Editor > Object > Visibility

Issue of current Shadow Catcher
Shadow Catcher can receive only shadows (limits are nicely summarised in this DevTalk) So I will keep Shader method, that can be used to "catch" also emission, indirect light or reflection that gives more sense in term of merging CG into image. Comparison ...
Example of Shadow Catcher issues -/- comparison with Shader solution ... see ground that doesnt catch emmisive rays and metal sphere reflects white plane ...

Edit 2021-05-05 Finaly movement :) Emmisive rays are calculated, but reflections and other mentioned above is still missing. So here is the shader solution for now ...

Shader for HDRi Environment

This material for ground plane object can also receive lights, indirect light or reflection.

This material gives you precise feedback if the HDR image lights correctly. If not, ground plane will be brighter or darker (or will tend to be a different colour tone) depending on image color deformation.

Material for ground (plane) is Diffuse shader with assigned Environmetal (Equirectangular) HDRi texture. The same texture used for World. The trick here is to use "Reflection" texture coordinates with negative Z value (-1). For smaller color differences between found and environment use RGB node.

As enhancement you can sync HDRi rotation. Just right-click on Z Rotation of World's Mapping node, choose Copy as New Driver and Paste Driver here in object ground material's Z Rotation (value becomes violet). Now when you change orientation in World material it will be copied to ground material too.
Showcase https://vimeo.com/159234378
For more examples and tests check out this Blenderartists thread.

Lighting by HDRi
is another topic, so just a quick tips. Use this World node-tree ...

Update for 2.9x (increased Divide node to move Mix node slider smoother).
Basic Color Correction

adjust Factor of the first Mix node (should be enough)

Shadows
If lighting seems to be ok, but shadows are still too sharp/soft the best way is to fix the HDRi image manually in some image editor supporting 32-bit images, select pixels in place of sun and decrease/increase exposure.
To affect shadows directly in blender you can try to add Multiply (Math) node before Divide (Math) node and adjust node-tree in this order:

first adjust value of Multiply (Math) node to affect shadows
change color of second Mix node to merge environment exposure
under Render properties > Color Management increase Exposure to bring general light appearance back
in case ground tint color doesn't match - add RGB Curve node to correct tint manually

Extreme example

Rendering – Be sure "Multiple Importance" is enabled in World Properties panel (value like 840), it should be checked by default.

Shader for Backplate (2D image)
In case you want to merge your CG with the backplate, simply use "Window" texture coordinates for shadow / light receiver. This material doesn't have a geometry limitation. In this example, a plane is used also, but it can be any shape. Scene is lit only by a sun with strength that brings ground image to background colours. Both previously mentioned benefits (shadow/light receiver and in this case general feedback of correct lighting) works here too. Disadvantage of backplate (compared to equirectangular HDRi image) is lighting inaccuracy and missing reflections.
Note: the same node tree is used for the world.

Note:
There exists OSL shader QUIP and QUIPCam for this purpose that gives you the ability to have a bit of movement in the environment too. But OSL isn't supported for GPU calculation and takes quite a lot of time to get a clean render.

Thank you for this answer. Your example was very userful for me :)

I'm gonna sound very stupid, I'm afraid. I read the whole BE thread, watched the videos several times, and I can't, for the life of me, figure out where this "HDRI" image texture file comes from.

OK, so no one is going to tell me where is this HDRi image file, or why do I need it just to hide the shadow receiving plane in my video? Come on, tell me, this unreproducible answer is a joke, right?

Awesome! Blender needs to figure this out. It's got to get a better way to catch shadows.

@yPhil The "HDRi" in question is the same as the world's environment texture. If you don't have an environment texture you will have to use a different method to hide the plane.

I don't see how the method described in "Shadow / Light Receiver ___ HDRi" could produce the right result even with a good HDRi map. The ground gets lit twice by the same sun: once when the image is taken, and again when the sun in the HDRi map lights up the diffuse ground plane.

I'll probably get myself defrocked for this because what I'm offering is more an alternative to shadowing because it's so easy to achieve and is completely independent of Blender's lighting restrictions, quirks etc.
The method is kindergarten level, crude even, but it works!

It's entirely flexible and has the added advantage of being able to
assume any shape a storyline demands. It can even move independently of its 'master', take on a life of its own!
Shadows -
The system uses a 2D alpha layered plane textured with the shadow movie or a still frame when no animation is involved.  This is laid at the actor's or object's 'feet' and parented to the same empty that's propelling it forward. (for stability)
It can just as easily be placed on a wall, or bent half between!
Shadow movies can be blurred in the VSE when a sharply defined version isn't desirable, the plane textured with that instead.
They are also rendered using OpenGL and with no lighting.  (Black on transparent)
A shadow is photographed/filmed as with any movie, capturing the actor's movements, but holding it (the actor) stationary.  I find it easier to either duplicate the Blend file and do the shadow in that, or create a new scene and copy paste (append) the actor into it, animation and all.  In the shadow Blend file all lighting is removed so you end up with a black figure doing its thing on an alpha layered background.
The examples above were rendered using OpenGL as png files, one for each frame and with the "RGBA" button pressed for the alpha layer.
I'd recommend setting up a fixed camera for this.  It will give you somewhere stable to come back to, should the need arise.
The cam is usually placed at a position that gives the best results for the job. This isn't necessarily from where the scenario's lighting originates.
More often it can be at its 'compass' direction only, and at a height and angle to suit.  In the Plant example, the shadow sequence was taken from about mid plant height and perpendicular to them.
The walking sequence was taken from directly behind and with the forward motion disabled.  i.e. animated but stationary.  Whatever 'stretching' is needed for the shadow's projection, is achieved by scaling the plane in that axis.  Keyframes can rescale as necessary.
The craft taking off was just a still alpha layered 'photograph' to get its basic shape from the sun's angle.  (It was not intended for this particular background photo)
The shadow plane was parented to the craft.
When the craft takes off and rotates, so too does the plane, so its Z height has to be held at its original setting.  To add realism the width of the plane was scaled down with a keyframe or two to more accurately reflect the sun's projection angle.
Where more complex distortions might be required, shape keys can be called upon.  (See the EDIT below)
-=================-
EDIT 10th Aug 2022
EDIT  10th Aug 2022 -
Added a fourth clip above...
The last video shrink-wraps the shadow plane so it follows 'terrain'.  (the hump in the floor)
It also encounters a wall and behaves accordingly.  For that, a duplicate of the plane was added and placed vertically under the floor.  It's ascent is tweaked to match 1st.


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UV Mapping Plane Single Side
I have applied an image to a plane in blender using UV Mapping however I want the image only on one side of the plane not both. I am not sure where the setting is for this.

This is the default or norm in Blender to have the texture appear on both sides. There is no setting to change this. This also doesn't need to be changed often as usually only one side of a model is showing.
The way I go around this to have the material appear only on one side is to use material nodes and have the base material on one side and a transparent material on the other.
It is a bit tricky if you don't have any experience with material nodes but just follow the node layout and it should work.
Just unwrap and texture as normal and setup your material and then add a second one, enable Transparency, set the Alpha to 0 and turn off the specularity.
As you can see below, both planes have textures but only one shows up when rendered. That is because I have added a transparent material to it along with the normal material and used the Geometry node to pass the materials to the different sides. One of the planes is on one side and the other is rotated 180 degrees around to the other side.

Here is the node setup for the material. (larger image here)

Can u explain how i add nodes and get it to how u have it

@BDGapps select the material and open the Node editor. Switch it to material and tick Use nodes. You add the different node types the same way you add meshes with the Shift + A menu.

"This also doesn't need to be changed often as usually only one side of a model is showing." Depending on the camera angle to the object, both sides can face, especially if the cube for instance has the top face cut out.

I do not believe that single-sided texture mapping is supported in Blender out of the box. But consider this tutorial as a possible way to accomplish that: http://www.blendernerd.com/double-sided-materials/

Quick and dirty: Make your image textured object 0 depth. So you have only a plane with an image on it. Create a second object with the real dimension and move the plane to the side you want the texture to. Join both.

To the best of my knowledge, Blender does not have a built-in setting for one-sided UV mapping. However, you can trick Blender into thinking that your plane has two distinct sides, which you can then UV unwrap independently.
To do this, add a Solidify modifier, set the 'Thickness' value to 0, and hit 'Apply'. Now, when you go to UV unwrap, you will have two sides to map, one of which you can set to an image and leave the other blank by arranging them in the UV/Image Editor.


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How to have a nice visual join between two colliding meshes?
I don't know if the answer is in the modeling, texturing or even the compositing part but my aim is to be able to achieve a nice visual look between two meshes (like in the render shown below).
The picture is a snowman scene and one of the worse parts of the render is the joint between the ground and the snowman.
When looking at it, it is pretty obvious that both snowman and ground are two separate objects and that is because when I tried modeling the ground as an extension of the snowman, the textures wouldn't apply properly and the overall look was even worse than the current result.
This is only one example out of many other situations in witch I get this kind of issues.
I'm interested in knowing what solutions could be found to that problem.

A first glance tells me that the crystal's light doesn't project shadows... You may have to turn on Ray shadow button in the light properties, and see if it look better.

IMO, modeling them as one mesh would be the best way to go.. or at least the snowman's body. You just need some seams in the right place.

Beautiful crystals!

i have the same problem posted in http://blender.stackexchange.com/questions/4922/how-to-integrate-knoll-to-soil. A blending of two textures is not sufficient for me. For me it would be more interesting to integrate the bump of the ground to upper object. Additional i want to add some partialy dirt on the stones, like washed out through rain. Similar effects could be intresting for snowman, e.g. some snow on stones, but using the bump map of stones as well. But how can we realize this in blender?

In 3D modeling this is often quite difficult.

You could make them the same mesh and join the geometry, then use a vertex-group or vertex-colours to blend between 2 materials (most obvious solution, check on tutorials for blending between materials).

You could cheat...

add grass (particle systems), pebbles, rocks etc - this is what happens in real life isn't it? It will likely increase your render times but hide the join.
you could apply alpha to the lower part of the mesh that meets the ground so you don't see a sharp change.
You could add a strip of faces which sits just above the join and blends between the 2 surfaces (with alpha on both sides so you don't see any hard edges), I don't recommend this but it can be made to work, you just have to be careful that lighting is ok and its not casting shadows on the faces below it.
You could render them on different layers and composite them, alpha blending parts of the lower mesh. (I don't recommend this but adding for completeness)

Wow Thanks a lot, these are all great ideas witch I haven't tough of (except for the adding grass, rock, etc... but my computer wasn't powerful enough) ^^' anyways thanks once more.

Procedural texture should handle strange surfaces like that very well. Image based textures need proper UV unwrapping.

use these two modifiers: Boolean (Union) + Remesh
The old way of doing it would have been to model them together by hand,
Having softer light around those areas makes them a lot less visible. That is to say you need light bounding around, Cycles does that by default.


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Split a mesh with a plane
I'm trying to split a mesh into two pieces along a plane like in this video, using Blender 2.62.
The closest I can come to splitting a mesh into two pieces along a plane is this:

Add a plane
Grab and move the plane to where I want the cut an existing mesh
Select the plane, then (and) the mesh
Apply a Boolean modifier

This indeed splits the mesh in two, but it tosses out one of the new pieces (intersection, difference, and union all do this, but they differ in which of the two pieces get lost). Is there any way that I can fix this problem with the Boolean modifier or another way for me to split my mesh?
My goal is to eventually write a script which splits an object into many equally-spaced slices along a given axis.

For the bit about them disappearing when you use a modifier, this is fairly simple enough, just duplicate the object and change the modifier Operation on one of them to Difference and on the other, set it to Intersect and target them at the same object that you want to use and split the other.
You should now have two separate objects and still be able to modify them via their unique boolean modifier, when you are satisfied, simply apply the modifier and separate them.
In the image below, I have two separate objects but each has a boolean modifier with the same target which is the plane (I have set its draw type to Bounds so the objects can be seen easier). I have also applied the boolean modifier to the top piece so I am able to separate it from the rest of the object.

Could you explain this please: "target them at the same object that you want to use and split the other."?


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Increase Cloud Evolution Speed?
I am trying out the Cloud Generator AddOn that comes with Blender 2.67.
I have created a a single cloud and selected the CloudPointDensity texture.
Under Turbulence I have changed Influence from Static to Global Time.
This causes the cloud to evolve and change shape as time passes. However, I would like to change the speed of this evolution and I can not find anyway to accomplish this. I have tried Time Remapping and increasing the FPS of the scene. None of these attempts produces any other result other than the default evolution speed.
Is this possible with Blender? Or does this border on feature request?
Thanks

I'm going to look at this later today. Modifying Time would have been my first guess, but now i read that you tried that already.. Been thinking about this question for a few days already.. We didn't forget about you! ;)

Have you tried changing the frame rate?

Just wanted to chime in: I played around for a bit with turbulence today. Still no solution.

Global time is basically just the frame number. As far as I know, Blender can't render in between frames, so there isn't a way to slow down global time.
(I may be wrong about that though. Maybe turbulence is computed as a current_frame / total_frames? In that case, you could try increasing/decreasing the number of frames. I don't have time to do a test case, at the moment.)
Instead, you should use "particle age" for the influence. To modify slow down the turbulence, you'll need to select the particles option when you first generate the cloud. This will let you edit the particle system associated with the point cloud texture. Longer particle lifetime = slower; shorter particle lifetime = faster.
See the Blender Wiki for the Point Density Texture
Edit:
Oh, you could also just render it at slow speed, then speed it up using a "speed control" effect in the video sequencer. 'Tis a hack, but may suit your situation.


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How to animate vertex color of an object?
Is it possible to animate the vertex color of an object?

perhaps you could clarify on the basis of what you would like to animate it. A morph between two color layers, or something more procedural.

two possibilities:

or to morph between two vertex colors layer in time
or to change , in same vertex color layer, the colors in time

please update your question with more details.

Cycles
In Cycles Render, it's rather easy. Create your two Color Layers and animate the MixRGB's Fac: value.

I'm not familiar enough with Blender Internal to find a suitable answer for that engine. Luckily, brecht provided an answer
Blender Internal

A similar setup works for Blender Internal, using two Geometry nodes for the vertex color, a Mix node to mix them and a Material node to plug the color into.

@brecht I tried and failed miserably, can you show a .blend?

http://www.pasteall.org/blend/22120

@brecht Thank you! I see, the viewport BI render doesn't seem to update (without switching from Render Preview to Texture Preview and back again), but a f12 regular render works fine.

manipulating Color Layer directly with Python as a function of frame number
We can animate a color_layer vertex by vertex procedurally with frame_change_pre handler, docs for which are here. This assumes that there is a vertex color map called  'Col', and that you know how to render Vertex Colors
import bpy
import random

obj = bpy.data.objects["Cube"]
mesh = obj.data

color_layer = mesh.vertex_colors["Col"]

def set_vcols(frame):
    i = 0
    for poly in mesh.polygons:
        for idx in poly.loop_indices:
            r = 0.5
            g = 255 / (frame % 255)
            b = random.random()
            color_layer.data[i].color = r,g,b
            i += 1

def my_handler(scene):
    frame = scene.frame_current
    set_vcols(frame)

bpy.app.handlers.frame_change_pre.append(my_handler)

If you go this route, while developing it might seem that your code is not being executed as you hoped, run the below code from console, then rerun your script:
purge the event list:
f_change = bpy.app.handlers.frame_change_pre
del f_change[0:len(f_change)]

Thanks but I'm not sure what can i make with this code.
What are the steps to use this script?
I have creat a cube, asign to it a vertex colors named "Col", run the script, but nothing appears

I now how to render the vertex color, i want to animate this propertie:
example: all vertex are red at 0s and all are greens at 1s

a gradual change ?

yes exactly a gradual change

Blender internal, but if there is a technique juste for cycle,
i want to know too for my knoledge


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How can I properly import Blender meshes on keyshot without geometry issues?
I can properly visualize this mesh on Blender (fig.1) but seems something goes wrong when importing to keyshot (fig.2).
It is like the boolean cuts get filled with some geometry. What kind of issues is this?
Thank you all

This is probably caused by ngons. Try to triangulate the model before export (or in the exporter, if it has such an option).

Triangulate works perfectly, thank you!

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


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How to establish the best texture resolution?
What are the benefits of a 4k texture compared to a 2k? Sometimes I use very large textures, weighing down the work, but without perceiving the benefit.
How can i choose which resolution fits my job best?
Thanks

In addition to cegaton's answer below, it also depends on the purpose of your textures. If you model for render purposes or rt render engines like game engines makes a huge difference.

@cegaton - can do, going to take a while...


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Led light through material
How can I get this glow like effect?
This is my model with two reference images. I wanted to recreate some bright touch keys like the ones with a soft glowing led that seems to pass through the material with a sort of transparency, but I can't get a realistic effect. I'm using just an emission node but it is not enough to achive that sort of subscattered appearance. Can someone help?
Thanks

You could try a variation on this (rather wonderful)  answer

It is not a bad question, but 'Led light through material' is a really poorly formed title. I think the question would benefit greatly if it had a normal title. I would recommend trying to define what you are asking clearly and shortly and form it as a question in the title. Something like "How can I recreate the soft glow effect on LED segment displays realistically using Cycles?" could work. At least try to do that with your future questions. It's just clearer, easier for everyone and you will most likely get better answers faster.

Thanks @MartinZ for pointing this out, I'll keep it in mind for future questions. I wanted to be concise, but since English is not my mother tongue I did not realize that I could not be interpreted the right way.

You need to do that in post. The compositor to be precise.
In the passes you need to enable the emission pass
In the compositor you can now see

Image
Alpha
Depth
Emission

You add a glare node and set it to fog glow and plug the emission in the color inout, play with the settings till it matches the reference
Now you need a mix Color, plug the glare node in the top and the image node in the bottom.
Set the mix node to add
Now you can play with the values, the higher the add factor the more it will shine and look like it's scattering in the material and coming out glowing.
But rigth now it's not what you want, you want a scattering look. You need to add an object index value to the object and use this as a mask in the mix color node to only add the glow effect where the object is, this will make it seem like it goes throu the object and not throu the air too.
Note that this is the efficient variation. You can use subsurface scattering but it will pump your render times into infinity and beyond

Thank you very much, it seems to me the most appropriate way.

In addition to enabling 'Glare' in the compositor, you should put some kind of material on top of the emmission. This could be transmission or something similar. Why? Because no lights IRL are a solid block of light - they at least have glass or (in this case) plastic on top.


text:
Need advices on the topology of this mesh
how can I improve the topology of this mesh?
It's just an exercise to improve my topology management.

If your render is OK you can keep it as it is, there must be simpler topologies like this one:

Yes, the render has no problem, my intent was to maximize efficiency with a topology as clean as possible. Thanks for the pictures, I will go for it

For hard surface modeling I wouldn't worry about keeping the faces as quads. I know some people will try to beat it in your head to keep it all quads, but if you have a non-deforming, flat face that is clean as an ngon, on a hard surface model it's fine. The key words are flat and non-deforming.


text:
How can I find a mesh's position when affected by a constraint?
So basically, I have a mesh that is moving via a constraint. However, because it is a constraint movement, I can't find the position of the mesh. So, is there any way I can find the current position of a mesh, even when affected by a constraint? (I mean like in numerical form)

Presuming you can see the model in object mode, Select it and press SH-S, choose "Cursor to selected".  The 3D cursor will jump to the model's origin point.  Press N and you can read off the 3D cursor's location.
If you want to store this within the Blender file, ADD an Empty.  It will appear at that location and it's own location readings at right will be the same as the 3D cursor's.
You haven't stated what constraint(s) you're inquiring about so I've just tested this out both with a path constraint and parenting the object object to another.  Both work as described.

Matrix world
Every object has a matrix world, that is the resultant global location, rotation and scale, after keyframes and constraints etc are applied.
To see the current global location, with the object active, go to the python console and type in C.object.matrix_world.translation
>>> C.object.matrix_world.translation
Vector((0.0, 0.0, 0.0))

>>>

to see its visual global location.  Might seem a fair bit to do but once you have typed this in once  to repeat press up arrow (history) , return.


text:
I want one object to "chase" another object
So for this example, let's say there is a red circle and a blue circle. The red circle moves in a circular movement. Example here is the red circle moving by itself: https://i.imgur.com/DVwlKzN.mp4
What I want to happen is that the blue circle moves towards the red circle every frame. What I don't want is the blue circle to mimic the red circle's movement like so: https://i.imgur.com/TaOpZnA.mp4 Is there some type of clamp I can use to execute this? (I'm no expert in python, so is there an easier way to do this?)

Chase:

View from top - Ortho view
An empty is placed at the center of the red circle's intended orbit and rotates. The circle is parented to this
so it rotates around the empty.
A narrow and invisible plane is added and has it's pivot point set to it's upper end.  This is then located at the red circle's center (SH-S)  and will act a leash.
The leash is scaled in length and rotated so it's other end is at the stationary blue circle.
The blue circle is then parented to the leash choosing the "Vertex" option. (child = blue circle)
The leash's two end-vertices (at the blue circle) are then shapekeyed to shrink the leash over the same number of frames (minus a few) as it takes the red circle to make one orbit.  You can have this happen (the intercept) much sooner or over several orbits if you wish.
When played the red circle does it's orbit and the leash is forced to follow and rotate with it.
At the same time shapekeys are shrinking it's length, automatically making it close in on the red circle.

By adjusting the leash's shape key F curves in the Graph editor, the nature of the intercept can be varied to suit.


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The difference of subdivision surface modifier between 2.7x & 2.80?

This is a plane with 1 level subdivision surface modifier, it seems that version 2.80 using a new method to subdivide and smooth the mesh. This is almostly different from the version 2.7x and other 3D softwares. Why the developers make this change? Is there any advantages of the new method?

Yes, 2.8 now uses Pixars OpenSubdiv. So there is a change on how they are computed and behave.
[EDIT]
I actually can't see why there should be a difference here from maya for instance. You may want to discuss this on devtalk.blender.org.


text:
Where are the light settings in Blender 2.8?
I'm trying to follow a tutorial but got stuck when I tried to setup the lights. Here's a screenshot from the tutorial:

Where are these settings in 2.8?

In Blender 2.80 the Light settings have been moved into the Object Data Panel.
Select your light source in the Outliner, then select the Object Data tab.
Light settings EEVEE:

Light settings Cycles:


text:
Why is the head bone missing from my Rigify rig after generating it?
I have been using Rigify to create a character rig, and I encountered an issue where the head bone is missing from the rig after generating it. I have tried to solve this problem through research and troubleshooting, but I haven't found a satisfactory solution for my exact model.

Are all bone layers visible?

@joshsanfelici I'm not sure, I'm not that used to using Rigify. I'm just trying to rig a simple robot but am unable to do so correctly. Thanks for pitching in to help by the way!


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Why does my knee behave unexpectedly when manipulating the foot control in Rigify Blender rig?
The first image shows the problem I'm encountering, while the second one depicts the desired result which I achieved through manual adjustment of the knee control. How can I achieve this?

hello, could you please share your file? https://blend-exchange.com/

Notice the IK bone that is depicted as a unfilled red arrow in the upper leg: try rotating it.

I detect that you are using a character imported via DAZ Studio?
Notice the IK bone that is depicted as a unfilled red arrow in the upper leg:  it is probably named something like "thigh_ik.R"
Select this bone and try rotating it.  It is used in place of "IK pole targets" in some armatures like DAZ Studio,  and it rotates the thigh/knee alignment. As you can see from the screen-cap, this arrow-like bone is rotated 90-degrees (Z-axis) from what you show in your screen cap, and in my case will rotate the knee/thigh pointing forward.

More convenient is to create and use a pole target that you can move/animate instead of rotating the knee_ik bone.  The knee_ik bone will then rotate to Track_To the position of the pole target.

Also, if you want to make the adjusted rotation of the knee to be the default, use the Pose>>Apply as Rest Pose (either of the first two on the menu should work).   This is analogous to the Apply >> Rotation to objects.

Thank you for helping out! I'm actually using a model I sculpted in Blender, so it's weird for it to have such behavior. So I think I'm understanding Rigify a bit more with your explanation here. I tried rotating thigh_ik.R 90 degrees, and it solved the problem when I tried to move the foot. So my goal is to eventually rotate this every time I want to move my foot to prevent any distortions such as the one in the first image I posted, right? But why is my thigh_ik.R rotated the way it is, and can I fix it to be like the one in your pictures, i.e to be faced forward?

@Animimo -- I appended to my answer above.  Good followup question.  If you accept  my answer, could you please click the check mark near the top left of my answer.  Us poor contributers work for the reputation points we gain, LOL.

Yes, of course. Thank you for the detailed answer!


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Random scale in two or more Instance on Points nodes
I have very simple question that is just too hard to summarize/find an answer to.
I've made this simple scenario because its easier to understand the problem.
I want to apply random scale value on each and every instance (cube) separately. But I have two (in my other project three) "Instance on Points" Nodes - one array instance in circular arrangement and other takes these circles and arrange them on line.
If I plug random value to first it will only change scale in columns.
If I plug it to the second Instance on Points node it will change diameter of circles.
It's nothing I would not expect but I dont know how to take all the cubes in output and rotate them separately.
I hope you know what I mean. Thanks in advance for any help.
Please note that this is simplified example and I know that in this case it can be done differently (use cylinder for example) but I need to know how to solve this in the way I described.

You need a little bit of reordering of the steps.
First make sure to set up all your instance points.
Don't forget to use Realize Instances node to make the instances' points readable.
And as last step - add the Cube instance.
This way you can apply scale an rotation on each individual Cube instances:


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Quaternion get a minus sign after full rotation
I'm making a rolling animation of my character.
After rolling 360 degrees, when the character gets to its initial pose, the rotation quaternion goes from (1,0,0,0) to (-1,0,0,0)
That's a known "feature" of quaternions: q and -q represent the same rotation. However, when the quaternion rotates 360 degrees, q becomes -q. you need to rotate 720 degrees to get +q again.
It causes trouble in interpolating between frames. the character will erroneously rotate 360 degrees if I copy the initial pose to the last frame. it is because one is interpolation between (1,0,0,0) and (-1,0,0,0)
Is there any way to fix it?

Hello. A solution might be to set a keyframe with the rotation to 180° at the middle of your animation that way the interpolation doesn't go the wrong way

When a quaternion keyframe causes troubles because it's inverted, you can use this operator to flip it's values without affecting its orientation.

Wow.. and there I was, about to launch an essay.. :D

I was worried about cycling animation. at the end frame the quaternion is inverted. That might cause trouble when mixing with another animation in the NLA


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Transparent video strip over background image
I have a video that I shot myself in front of a solid gray colored wall. Now what I want to do is, place an image in the back and put the video of myself in front and make the gray areas in the video transparent so the background image shows behind me.
I tried putting the assets in to the sequencer and added Effect Strips and played with the Alpha Over / Under settings to no avail.
Is Blender enough for this or am I going around in circles?

What you are trying to do is a luma key. Do a search for that.

Try this tutorial: https://www.youtube.com/watch?v=dI1kMT3O6uk


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how can I make the color looks whiter

I am just wondering how can I make the color whiter but also metal-like. the car model should have a white-painted metal shell. But I cannot make the color look like white. Although I put white color in there, it looks silver-like. Can anyone help me out to make this look like white-painted metal shell? Thanks.

https://blender.stackexchange.com/questions/62568/how-do-i-create-a-reflective-white-material


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Blender 2.8 malfunctioning
I just upgrade my blender 2.79 to 2.8, however when upgrades end, my mouse basically lost all its functions. I cannot click the object, cannot select object, all the hotkeys dont work, since like tab to edit mode, g to translate, r to rotate since like that. I cant even do anything with the default cube. The only thing I can do is click all the buttons on the interface. I am wondering what happened. This upgrade really made my day.

Do you mean all this happened after you installed 2.8?

reset your preferences to defaults and select the Blender 2.7X Keymap if you want your advanced keyboard shortcuts, then add the cool new pie menus to the keymap so you have the best out of 2 worlds

@HenrikD: It must be more than that as I don't think GRS was changed as well in 2.8. And user Roger has problems with mouse, too.

@Lukasz-40sth I suspect, a corrupted preference is somehow loaded due to some kind of problem while updating to 2.80. The preferences control everything and that would explain it perfectly.

@Lukasz-40sth: yes it all happened after install 2.8. I deleted 2.8 and reinstalled 2.79 everything becomes normal again

@HenrikD: I did want to try that, but when I open my keymap, there is nothing in there, plus I cant even find an add short cut or edit hotkey button. I redownload 2.79 and deleted 2.8 everything becomes normal again. I do not know how to use my 2.79 setting to 2.8 could you plz explain a bit so that I can take a shot?

which OS are you using?

@HenrikD: win10


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Can I texture one object part by part
I have a somewhat complex model like this. I made the whole building separately(top middle and lower part are different objects, fences and pillars are also different objects). I am just wondering what is the general way for making texture of this whole building. Do I do UV unwrapping one part by one part (I mean do the UV unwrap for pillar, and another UV unwrap for fences and so on) for texturing, or I UV unwrap the whole building into one picture, and use photoshop for texturing. This is the first time I do texturing for complex model like this, please offer me some experience and general steps. Thanks

You can do both way. If you want to texture it with multiple images, assign different materials in edit mode to the different parts, and DO NOT create multiple UV maps.

Personally, I would keep the parts separate and texture them separately.  For me, it makes it a lot easier to manage and th change later if I want to.
Having said that, doing it all as one UV map is an equally good way of doing it.

@FFeller are you suggesting I cannot make one UV map for each separate part? Or I just cannot make different UV maps for the whole thing

Don't create multiple UVs in this tab: https://docs.blender.org/manual/en/latest/editors/uv/layout_management.html#multiple-uv-maps If you use multiple materials, every material's texture can use the whole UV area so the different material's uv islands overlaps each other. But every UV map contains the whole mesh, so it makes no sense to use multiple UV maps in this case.


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how can i make uneven distribution of lattice without changing the shape of object in the beginning
I want my lattice to the shape as i showed in the beginning. the edge inside lattice is not not evenly distributed, becuz i want my plane to bend along those lines. How can i manipulate the lattice to that shape without changing the shape of my plane immediately?

I understand if we i use edit mode to lattice it will cause my plane to distort. I am just wondering how can i change the bending position to like this with out deforming my plane in the beginning. plus, i googled but did not find satisfied answers.

maybe use Mesh Deform modifier or even Surface Deform as your mesh is flat. You'll be able to make the cage mesh exactly fit your object mesh.

I don't know if you could have something very accurate with a lattice. Maybe you should try shapekeys or, if you have a reason to prefer a modifier, the Mesh Deform modifier or even the Surface Deform, as your object is a simple plane:

Create the object A, the one you want to deform.
Create the object B, a subdivided plane, it's the object that you'll use as the Surface Deform target.
Align its edge loops with the object A vertices.
Give your object A a Surface Deform modifier, choose object B as the target, click on the Bind button.
Select the object B, go in the Properties panel > Data > Shape Keys and create the shapekeys.
Now your object A will deform rather well.

thx for ur answer! I do not have a preference. I just want to bend my surface. I am new to blender and lattice is just the tool i googled and found. So if i just want to bend a surface, which tool will you suggest me to use?

the simplest one is to create shape keys on your mesh without any modifier, search for a tutorial on youtube: In few words you need to create one basis shapekey which will be the undeformed shape, them create as many shapekeys as you want, one for each deformation you want to create, then play with the vertices in Edit mode, and once back in object mode play with the value...


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Geometry Nodes: How to make a vertex color gradient on a tree depending on distance to root point?
I'm trying to create a vertex color gradient on a mesh created by converting a branch made with hand drawn curves to a mesh using geometry nodes.
I want to color each edge ring on the created mesh depending on the distance to the origin point of the branch, but crawling along each parent branch. So not only the distance from the point to the branch origin, but also including all the point along the branch before it.
I also need to color the leaves which are instanced on the branch a solid color, of the closest edge ring to the origin point of the instanced leaf.
How the branch is looking:

The branch contains separated splines:

The result I'm trying to accomplish, made using a MEL script in Maya:

Is this possible to achieve using geometry nodes, and how would one go about doing that?

What algorithm did you settle on in your MEL script for jumping the gaps? You want the total length along the branches to the root?

@RobinBetts The branch is constructed with separated geometry using predictable cylindrical topology in Maya. The objects are parented into a hierarchy with the main stem as the first object. The script loops over every edge loop on each piece, backwards along the hierarchy.
I jump the gaps by finding the center point of the closest edge loop to each object's pivot point.
So what I'm trying to do is get the length of every point on the spline, crawling backwards along the branch to the origin of the branch.

'Centre point of closest loop'  (hopefully, parent)' If a similar method is acceptable in Blender, I think that should be possible in GN. If you mean to construct  the tree in GN, that would be simpler still .. the construction data would be there without a 'closest' search.

A good approach with Geometry Nodes would be to convert the Tree Curve to Mesh and merge the points at the base of the branches. Select the end points and run Shortest Path set up for these points with End Point the base of the tree. Convert the resulted shortest paths to curves (splines) and calculate each spline length. Assign distance attributes to each curve points based on spline length and transfer them to the closest points in the original Tree Curve object.