text:
How can I modify the frame rate without changing overall animation speed?
How can I change the animation fps when I already have finished making an animation? I already did an animation and I don't want spend some time recalculating the time by hand, is there a easy way to change the frame rate without making the animation speed up or slow down?

It can depend on animation. E.g. one without objects like lightning strikes in frame can be remapped on newer FPS using Time Remapping options in Render Output. However if there are some effects appearing and dissappearing quickly this may not work and you might need to scale keyframes in the Dope Sheet manually.

The most straightforward solution I have found is to render the animation to JPG or PNG and then import those images into the video sequence editor. You can then animate those images in the frame rate that you want. You will have to do some computations first and you will need to understand what is happening, though.
CASE 1: Lowering the frame rate.
This is the easiest. To lower the frame rate without changing the length of the animation we need only drop frames in the image renders. For example: You have a 60 second animation at 60fps. That is a total of 3600 frames. To convert the animation to 60 secs at 30fps we need to drop frames to reduce the total frames to 1800. This is done by setting the "Frame Step" to 3600/1800 = 2 before animating. You can do the same kind of computation---a) compute total frames required, b) compute the "Frame Step"---for any other frame rate you want.
CASE 2: Increasing the frame rate.
This is where you need to compromise. Increasing the frame rate while maintaining the animation length means you have to add frames! Where are you going to get those frames? Depending on your particular situation maybe you can just duplicate frames. In some cases you may need to manually insert new "in between" frames. You may need to use the '####' frame number format judiciously.
For example, to duplicate each frame. a) In the output filename write down "image-####-01" as the file name mask. Animate.
b) Now change the filename to "image-####-02". Animate again into the same directory. c) Add the images into the video sequence editor and animate into the final format.

When increasing the frame rate I would recommend frame interpolation software.


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A powerful graphics card, or cloud render farm, which is more effective?
According to the tests that I have seen, the render speed difference CPU vs GPU can be almost 60 times in favor of the GPU.
GPU renders using the graphics card, CPU using the CPU, am I right?
So, Is it more effective and profitable (in terms of rendering speed and in terms of money, of course), to buy a powerful graphics card than to build a cloud renderfarm?

Depending on your needs - GPU or GPU and cloud render farm could be the better option.
If you only create still images then installing a good GPU could help more than a render farm. Rendering one quality final image at a time will only keep your machine busy for a couple of hours at most. (Well, longer render times can happen but most of us tend to keep render times to a minimum). When you consider the time it takes to upload your scene and textures, the time benefit can drop when remotely rendering a single frame.
If you are rendering animations then you will want to use a render farm, but a decent local GPU will also benefit as you can quickly see a finished frame to get lighting and materials right before sending to a render farm for final rendering.
If you are able to render your images using a GPU, then you can also make use of GPU with a render farm to reduce your rendering costs. Some render farms like render.st offer GPU rendering and if you are building your own farm then Amazon's AWS offers GPU instances (g2.2xlarge and g2.8xlarge).

I am amazed no one mentions TDP as a rendering hardware criteria.

CPUs will win render time per Watt.
GPUs will win render time per Cost and also render time per meter^3 - but only on simple scenes! Throw something more complicated at GPU and it will struggle (like bidirectional path-tracing).

The best cost-effective solution are second-hand GPUs with Fermi architecture (GTX 580, Tesla M2090, etc.), but they support only CUDA compute 2.0 and it's in question how long this support from Blender will last.
What I would do however is to pay a little more for Maxwell, which is not that power hungry and has more GPU Ram.
Also when paying that much for hadrware, I would look around for commercial renderer that might do the job faster on cheaper hardware than Cycles! Remember Cycles is no wonders - it's just a simple path-tracer that struggles a lot with volumetrics, glossy and blurry transparency. For example Corona renderer utilizes some really smart algorithms on CPU to be even faster than GPU renderers on complex scenes.

GPU rendering will almost certainly be FAR more cost effective, since you can fit several GPUs into one computer. You could also hybridize and use Blender's built-in network rendering utility to run just a couple of computers with multiple GPUs for rendering. What I would do, would be to buy a few of THESE: http://www.ebay.com/itm/NVIDIA-Tesla-M2090-6GB-GDDR5-PCIe-x16-GPU-Computing-Processor-VIDEO-CARD-/281723734547?hash=item41980b0a13:g:R-YAAOSwyjBW5vQe and use them for rendering.

Thank you very much, I have not heard before about this option, very interesting!
I just found out that GPU  rendering is limited by the memory of the graphics card, so the scenes that require more memory will not be rendered at all (I was hoping that in this case, the rendering will be slower, but apparently it will stop), so now I think that the CPU render farm is also a good option.

These older NVidia cards have something like 6Gb of ram, and the newer ones closer to 25! You must be rendering HUGE scenes to need more :)

source: Stack Exchange

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

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Cycles vs Internal for a small animated outdoor scene?
What are the pros and cons for using cycles to render an outdoor scene?
Note: I have access to a Nvida GTX 670, so I can use CUDA to speed up the cycles rendering.

This is easy. Blender Internal: quick rendering. Cycles: more accurate, making it easier to achieve photo realism. I leave the task of a detailed answer to someone more knowledgeable than I.

@NathanOsman BI is quicker by default, but once you start enabling things to make it look more realistic (AO, environment lighting, indirect lighting, etc.) in my experience it ends up slower than cycles (which is actually designed for animations).

Related: How is Cycles different from Blender Internal?

CVed as a concrete answer just depends on too many factors (what kind of look you are going for, the exact nature of the scene, the complexity of the scene, etc. etc.)

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


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Baking only light maps in Cycles
I was super excited to see that baking functionality has finally made it into Cycles. But I'm a bit confused about its usage. There are a lot of options in there. I'm able to get baking working just fine I think, but I'd like to back just a light map. There doesn't seem to be an option to combine bakes (except for one big combination of every thing). So I'm guessing I need to bake multiple maps and merge them in Photoshop. I'm just not sure exactly which ones I need. I'm guessing it would be Shadows, AO, Diffuse Indirect, and Diffuse Direct? Am I missing one? Is there some way to have Cycles bake those four together at once?
As a side question, just because I haven't tried it yet, if I make a second UV channel for my light maps (say one using Lightmap Pack in the UV tools) and set the image that I light map on to use that one while keeping the actual materials on the first one, will that give me the results I want? I don't want my materials to go wonky when I create the second UV set but I've never worked with multiple UV channels before. Certainly not in combination with baking in Cycles.

The Combined pass does what you are asking in the first paragraph, if you tried that and it did not work, it would be helpful if you explained what about it looked wrong.  For the second question, sure.  The uv map node can be used to select the UV set for any individual texture.

The combined pass also baked in the actual image texture that I applied to the model. I'd like to be able to use the result as a light map in Unity. Wouldn't it mess things up if the texture image is overlaid on top of itself? I found this thread with an example output from Beast light mapper which describes what I mean. Beast has no texture image data in the output: http://blenderartists.org/forum/showthread.php?242197-Lightmapping

normally I just add a second node tree within the same Material for things like this.  Whichever Material Output node is selected is the one that is used to render/bake to.  So you can just bake the lightmaps with a diffuse only material and then click the Material Output node for the colored materials and bake again to a different texture.  This way, the same 1 Material can be used for multiple materials and in a way that also has the characteristics of different passes in a way that is easy to select and alter.  This does work better for outdoor lighting since the sky can be used as lighting

So basically I'd have a second node with just a white diffuse? I thought about that, but then wouldn't I lose all of the bounce light data that comes from having properly colored materials? It still seems like combining the separate passes is the best option, but I'm just not sure which of the options are related to light and which aren't. I know what works in my simple scene but I don't want to miss anything.

Basically I think you just want the direct and indirect passes, which you can then combine. Though if you have diffuse, subsurf scatter, glossy, and transmission in your materials, that will be quite a lot of baking. . . You might be better off baking combined, then subtracting the color passes (which will result in the same thing).

Wow. I feel like an idiot now for not thinking of subtracting out the color pass. That's way easier than what I was thinking I had to do. If I can find the time today I'll try to make a test scene in Unity using that method to see how it turns out. Thanks!

We are doing the exact same thing, although my approach to the problem is slightly different.
Like you I created a second UV channel for the lightmap while handling the other materials on the first one. Once I unwrapped the object to the second UV channel I duplicate the entire object, remove all the materials from the clone and add a simple white material to it.
Then things start to get a bit complicated. Let's say there are several objects, for example a wall, a floor and a ceiling. When I bake the wall, I activate the clone of the wall, while hiding the original wall object. The original floor and ceiling objects stay active while their clones are hidden. This way you can retain the bounce light data that comes from the unchanged original objects.
It is basically the same procedure as having a second node tree in the materials except that you're switching on and off objects instead of node trees in every material on the scene.
I'm not sure if this is the smartest way to do it, but I don't have to bake several passes this way...

That works, I use something similar now. However this becomes inaccurate if the object is not convex and is bouncing light onto itself. Changing its material to white changes the lighting then. Is there any better way to do this in Blender since 2014?

Simple node setup for lightmap baking:

Basically, the diffuse color is only present in the indirect lighting, this way everything is correctly contributing. You just have to multiply your diffuse textures with the final lightmap.
The emission shader is only present for previewing the lightmaps here, connect the diffuse for baking.


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How to prevent Blender from disabling dyntopo when exiting/entering sculpt mode?
This is one of the most annoying things while sculpting with Dyntopo enabled - it switches itself off automatically for various reasons eg. going from sculpt mode into object mode and then back into sculpt mode or undoing too far, to the state of affairs where Dyntopo was disabled.
I had to redo so much sculpting when I realized that nothing suddenly went wrong with my mesh but that I forgot to re-enable Dyntopo that it becomes a major pain. I am aware of the Ctrl + D shortcut to quickly enable Dyntopo, but it just too easy to forget about re-enabling it.
Is there a way to keep Dyntopo enabled by default or prevent it from switching off, maybe at least with some clever Pythong scripting?

This problem has finally been noticed by Blender developers and included in 2.78 release.
"Enable dyntopo re-entering sculpt mode"
https://developer.blender.org/D2059
Dynamic topology will be re-enabled automatically when entering sculpt mode, but only if uv's, vertex colors or triangulating won't be affected.

Need further instructions. What do I do with that script?

You cannot because of the way the code is. When you are going out of Dyntopo, Blender has to synchronize you data, your Dyntopo sculpt, with the rest of Blender.
Or should I say you could change it if you were willing to code it?

This is a good answer, but it could have more information. Could you describe why it was coded the way it was? Could you add sources for your information, so others can do more research?

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


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How to connect the vertices of two separate objects?
While I was modelling a bird I ended up in a dead end and I do not know how to get out. I created the eyes of my bird as two separate objects using the mirror modifier, but now I can no longer connect the eyes vertices with those of the rest of the face because I have two different objects.
If I join the eyes vertices with the face/body vertices using Ctrl+J I will lose the mirror modifier, but I don't want to loose the mirror modifier for the eyes.  So I don't see a way out from this situation.

apply mirror first. now you can join it with CTRL + J

I know,but if I do it,I will lose the mirror feature and I have to model two eyes instead of only one. As you can see from the picture,I need to complete the modelling of the face,but i can't do it if I can't connect the eyes vertices with the rest of the face vertices...

Could you not work with one eye and your faced joined up and mirror afterwards?.
Highlight the eye vertices in edit mode with  with C or B then separate by selection with P and apply the mirror to new object creating your second eye. As long as it lines up nice it would get you your mirror option back.


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How to get list of all images in a scene with python
I am looking for a way to get a list of all the images loaded into Blender at that point. I want to use it as a check something like:
file = "name"
if file not in list.of.images:
   image = bpy.data.images.load(filepath)

know of any ways to do this, searched and searched and haven't been able to find anything.

If you just want to iterate over the images:
import bpy

for img in bpy.data.images:
    print("name=%s, filepath=%s" % (img.name, img.filepath))

Note this could contain 'render result' and materials which you might want to filter.
See the docs to see what attributes could be interesting like 'file_format', 'filepath', 'filepath_from_user', 'filepath_raw'...


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Can Krita and Blender be linked?
I have tried to look for myself but have not found the information I'm looking for.
I've seen that one can use the digital painting software Krita in connection with Blender.  But I do not remember how to do so.  Is this possible?

please elaborate, not sure what your asking

I'm sorry if I make a mess.
I understand and read English well. but the spell and get proper sentences is difficult.
So I try to improve myself. but it is not easy. I'm glad to see there are someone that can understand me
sorry again.

I couldn't find anything to do with Krita, but I do remember a synchronisation addon for blender that would allow painting in Gimp and seeing the texture automatically update in blender.
Here is a video of the addon, called 'External Paint Autorefresh' (Previously called 'Blender-GIMP Autorefresh'), in action and here is the site for the addon.
The site lists the features as:

One-sided modes. Hit a shortcut in your image editor to make the    texture update in Blender. Hit a shortcut in Blender to make the
  texture update in your image editor.
Two-sided mode. Work in your image editor while the texture updates    by itself in Blender, or switch to working in Blender while the
  texture updates by itself in your image editor. The updates happen
  only when you are actively tweaking the image, and at a frequency
  that you set.

This was great.
Thank you.
Do not know which I like best. GIMP or Krita.
so good to be able to use both.

You could set the path to Krita or any other external image procesing application in Blender's User Preferences accessible from the file menu.

From the image editor you can launch Krita with the image loaded by chosing Edit Externally. When returned to Blender refresh the image with Reload Image or Alt-R.

Yes oh, Yes, that was what I remember
But I forgot how.
So thank you so much.


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Using a background image to model in Blender
I have chosen the book BlenderBasics_4thEdition2011.pdf to use in teaching my first 3D Animation Class using Blender.  In it, on page 38, there is a lesson that uses a background image as a guide to create a 3D logo.  The text says to scroll down on the Transfom Panel to find the "Background Images" panel.  I cannot find that panel.  I have downloaded the latest Blender 2.72 release.
Can someone help me with this please?  I have done a couple Google searches and found images of that panel but I can't seem to find it on the Transform panel.  What am I doing wrong?

Press [N] to open the properties tab; You'll find it there.

Thank you!  Pressing N was the key.  It is obvious I am a novice to Blender but I am learning.  I appreciate the quick reply.

Press N to open the properties panel on the right side of the 3D view (if it is not already open)  Then scroll down till you see backround images and click add image.  To see the image you must be in orthographic mode and a side view, pressnumpad 5 to toggle orthographic/perspective mode and numpad 1/3/7 to go into a side view.


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BGE: How to create a countdown timer without using debug or python?
Is it possible to create a timer in the Blender game engine without using DeBug or python? I can create point systems using dynamic text, but just can't figure out how to create a timer.

In the title you mention logic bricks, is this for the game engine?

You can add a game property to an object, of type "Timer". For my BGE project, I created an Empty named "Clock", just for this purpose. It has one game property "GAME_TIME", as shown on this screenshot:

You can use this property to keep track of time, as it'll increase as long as the game is running. You can also set it to 0.0 to restart the timer.


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Can you paint parts of an image onto another image?
Is there a way to paint parts of a source image onto a canvas image?
It's also important to use scale while painting.  For example, if the source image is a heart, can I paint it on the canvas image in different sizes?  How can I do this?

You cant really do that; you'll want use the texture painting tools instead.

@GiantCowFilms huh?

@gandalf3 Wait.... what canvas (I thought he meant dynamic paint)?

Hm.. Could be, but I didn't get that impression at first. I think the OP wants the texture painting tools (clone brush? Or maybe brush textures?).

I know it must be possible. I did it once by accident. possibly stencil option? I could paint in different sizes as I zoomed in or out. But it painted with opacity even with the brush power at 100%. Could be due to a mask. Not dynamic paint I'm looking for, think that is for animation(and way above my level).  To clarify my question: source image= what I want to paint. canvas image= where I paint on and what will be the image texture for an object (mesh).  Thx

@Toonpix updating answer... they've changed the options since I last used this tool

@GiantCowFilms that's what I need but am lost at step 8

@Toonpix do you wan't paint a pattern for hearts or one heart?

@GiantCowFilms  it works!   the hearts was an example to try and explain that  you cold use the same part of an image and paint it with different sizes. I tried with your answer and steps and then used 'stencil'. It goes exactly how I wanted after a month of trial and error. Glad I found this useful site. I can't thank you enough, have a great weekend and holidays.

@Toonpix could you mark it as accepted, it closes the question (its that check mark button on the upper right corner).

You need to use the texture painting tools:

Hit Tab to enter edit mode
Hit A to select everything and then UV unwrap you object Usmart UV project
Change your view to the UV image editor
Open your image that you wan't to paint on (You can create a new blank one as well)
Change your view back to 3D
Change into texture painting mode:
In the slots tab, set the painting mode to image, and select your image from the drop down.

Set up your brush
Configuration:

Set the Texture to you're image:

Set the brush mapping to tiled adjust the settings to make it look right.

Another option would be to use the Clone Brush in Texture Paint.

This requires two UV mapped images with two different UV-maps

This is also useful to add dirt, rusty edges etc. to a texture.

With the recent versions of blender, you also now have the option to use a brush texture as Stencil, and when setting the texture to use Stencil mapping in either Brush texture or Brush Mask texture, you get a floating drawing of the image in the 3d view from user perspective. You can rmb to move it, shift-rmb to scale it and ctrl-rmb to rotate it. With the use of a second image in the Brush Mask channel, you use alt-rmb ot move, shift-alt-rmb to scale and ctrl-alt-rmb to rotate that mask and can combine to create interesting effects.


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BGE: How to make an object leave [skid]marks on another object
I want to know how to make an object leave marks on another in the game engine, like skidmarks as in this video. I'm not looking for a tutorial, just the logic of it.  How can this be done?

The best way to do this (and I tested) would be to have your trigger object (tires) rigged with an Edit object actuator set to add object : Activate upon a collision with ground or a sharp turn (Make sure True level triggering is on).
Set the time to 30, and the target object to be a plane textured like a portion or you tires tread. Alpha channel turn down.
I got good effects with a rolling monkey head, so hey; why not a car?

I want to try that, it sound really neat (the only PB I can see is the potentially uncontrollable polycount increase) so ; I already got an always pulse sensor on my car object, I connected it via a AND to a Edit actuator set to add a small plane I made, but nothing happens ; What steps am I missing?

OK So the "mark" object has to be on another, hidden layer. Now it works, only my 30 objects won't stay there, they follow the car :)

...Aaaand just set "time" to 0 to leave the marks on the track. Now I just have to replace my AND w/ a python module that (pretends to) manage friction (sharp turns, braking & accels) Vince, this is excellent, thank you very much!

Problem is it kills the performance... Damned, how can I just scratch the texture's surface?

Well, they don't need to stay there forever, you can make them disappear after some time. also at only four vertices a-piece it shouldn't be a problem. Maybe slow down the true level triggering delay value?

I did this, and it worked very well B TW, leaving less marks, nice ; No, my PB is the sensor : Somehow I can't get my rigid body to just stay put on the track plane, only hovering slightly, and a (property-based) collision sensor, when "on the track" oscillates True/False, and THIS is what makes is slow. The actuator is doing a good job, Your method actually works.

Are you wanting your vehicle to be able to tip and die? otherwise it just needs to be Dynamic phisics type


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"No valid selected objects." - Preventing me from baking material
When i move my mesh piece to another layer.
Blender either crashes on latest version.
or says this on older versions:  "No valid selected objects."
When i have it on the 1st layer however it does bake.
but its full of hidden objects that are interfering with my bake.
hence i am trying to bake on another layer.
Any idea?

Additionally, I found that you must have a closed mesh object as well. For most people this isn't relevant but it is what fixed it for me.

In my case I had to select the object in the top right corner list

In the bake options see if "Selected to active" is ticked ON.
This is multiple object bakes.  Tick if off and try again.
make sure yout TEXT Image node is slected too

I needed to ensure Diffuse UV was selected in the SHADING mode, under Normal/Map node. For some reason this was blank for me, and I just needed to reselect the only available option.


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Is there an unsubdivide function in Blender?
I am wondering if there is a modifier or tool that will essentially undo a subsurf or subdivide command.

You can use the 'Decimate' modifier set to 'Un-Subdivide' mode:

Increasing the number of 'Iterations' will increase the number of times the modifier un-subdivides the object.
This works particularly well with quad based geometry. Below, the monkey on the left (that had a Subsurf modifier applied) has 8,000 vertices, while the un-subdivided monkey on the right (with 2 iterations) has 2000 vertices, with all details preserved well.

Lets add a note that unsubdivide is a destructive operation that usually destroys UV maps to unusable state.

The Cleanup Menu has an option called ' Limited Dissolve '.

This turns the mesh on the left side into the mesh on the right:

As you see, it treats all surfaces that are adjacent and have a consistent 'normal' direction as one surface and joins them .

What I found today is that you can also use Ctrl+E and there's an 'Un-Subdivide' option but I don't know if that's the same as the modifier.

Worth mentioning that also the UVs get messed up the same way than with Decimate: http://bit.ly/unsubdivide

While this is destructive and the decimate modifier is not, this was perfect for my use case. (Too many subdivisions and unable to undo -- it can happen!)

There's also the option of using Decimate and then the Remesh Modifier.
They are both under the Generate section of the Add Modifier drop down.


text:
Is it possible to unhide only part of a mesh?
So I'm working on a mesh with sub-meshes, and as I work on various bits of the project, I hide other parts to make it easier to see what I am doing.
So I work on one thing and hide a few predefined vertex groups and a random group of vertices, and do more work.
Now I want to make a change to one of the vertex groups, and I'd like to unhide only that vertex group.
I haven't found a way; has anyone else? Is this worthy of a feature request?

I liked all of the suggested changes to the title except the substitution of "dehide" for "unhide". "De hide" is what you get from a cow or pig.

Further, "unhide" is used in the Blender manual 118 times, "dehide" not at all. But thanks for the suggestion, anyway.

Border-clipping can also be handy in these situations (Alt+B)

I think you might be interested in the Mask modifier.
This modifier will hide everything except the specified vertex group, or the other way around if you have the invert icon selected. To hide multiple vertex groups, you can add multiple modifiers:

Make sure the modifier is enabled in edit mode (triangle icon).

Since posting the original question, I have discovered a technique for doing this in edit mode that is different for the one proposed by Gandalf3.
When elements are selected and then hidden with the H key, those elements stay selected. When you unhide them using the key combination, ALT - H, all of the hidden elements are unhidden, and they are all still selected. But if after each group of elements to be hidden are selected, they can be assigned to a new vertex group, before being hidden. Now, when the hidden vertex groups are unhidden, they will still be selected, but any of the selected vertex groups can be deselected by using the deselect button associated that vertex group, and the remaining selected vertex groups can be rehidden by pressing the H key.
This can be a particularly useful alternative to the mask modifier, particularly when the modifier stack is already large.


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Control a property with no socket (color ramp swatch, etc) from a Group Node input?
Sometimes I create Material Groups to be used as appendable reusable assets. Unfortunately sometimes parameters I want to control using a Group Node's slider are not available for routing to a Group Node's input socket. Some examples of these are the Color Ramp and the Mapping Node.
So here's what I want to do:

Can this be done? If so, how?
Thanks!

All the functionality of the mapping node can be reconstructed fairly easily (you definition of easy math may be different from mine) via some math nodes, color ramp is a bit trickier but I believe it is still possible.  Would you be open to such solutions?

Could you please add a small example file with the node setup?

@batFINGER You got it! A .blend is now included.

@PGmath I'm certainly curious about how you could do that, and it would be useful. A solution that doesn't vary by node type is ideal (drivers?) - but if that can't be worked out, then at least being able to make something like a color ramp is better than nothing.

@Mentalist  The disadvantage to making a homemade color ramp is that it would have a set number of color swatches, and you obviously can't make the nice graphical display etc.  But if you are just controlling it via a group socket neither of those should matter.  The homemade mapping nodes, on the other hand, is extremely useful, even for normal use.  I'll work on an answer showing those two, if you can think of any other similar nodes I can try to make them from scratch too.

@PGmath Awesome! Thank you for taking a stab at this. I think the Color Ramp, even while having a limited number of gradient sliders, would still be very useful as a tapering function, since I don't know of any other way to create a falloff curve (although I realize it can be done with math). So yeah, both of those would open up more possibilities.

I finally finished my answer, I also included a .blend file with all the nodes so you can just append them when you need to if you don't feel like copying all my screenshots.

What you are asking - it's basicly the Map Range node

As far as I know, I don't think it is possible to drive a Color Ramp or Mapping nodes from another socket (but I am not super experienced in drivers).  However I have managed to re-create the color ramp and mapping node with math nodes, which you can plug inputs into directly.

Color Ramp
Unfortunately there is no way to create a group node exactly like the Color Ramp, with addable and removable color swatches.  To get around this I have created a node with two movable swatches, you can then combine multiple of these nodes together to have the functionality of multiple swatches.
The theory:
The two input colors are plugged directly into a Mix RGB node.  The two Pos inputs need to be sent through a function and plugged into the mix factor.  The position of the first swatch needs to be mapped to $0$ to get just the first color out of the mix node.  The position of the second swatch needs to be mapped to $1$ to get just the second color out of the mix node.
The math:
Here's a graph to visualize what we are trying to do, on the x-axis is the input factor of the color ramp, on the y-axis is the desired output, $a$ and $b$ are the positions of the two swatches.

With some simple algebra we can find the equation of the line to be:
$$
y = \frac{1}{b-a}x + \frac{a}{a-b}
$$
The math nodes below are simply replicating this equation.  The final Add node also has Clamp checked to clamp the output to the interval $[0,1]$, which is what the mix node accepts.

Mapping node
The mapping node has three functions it can Translate (move), Rotate, and Scale the texture.  Since often not all of these are needed I will create separate group nodes for each of these functions.
If you don't have a decent understanding about how texture coordinates work you may want to read my answer here.  The basic theory of manipulation texture coordinates is to separate the components of the vector with a Separate XYZ node, manipulate the components individually, then combine them back into a vector with a Combine XYZ node.

Mapping Node - Translation
Translation is easy, to translate $V$ to $V^\prime$ just add the desired amounts to each of the components of $V$.

In the above node setup I actually used Subtract nodes instead of Add so positive values will move the texture to the right instead of left.

Mapping Node - Scaling
Scaling is the same as translating, just multiply the individual coordinates by the scale factor instead of adding.

Mapping Node - Rotation
Rotation is a little more complicated and I won't take the time to derive the equations here, but they are pretty standard pre-calc formulas.  Here are the formulas for rotation.
Around the x-axis
$$
\begin{aligned}
x^\prime &= x\\
y^\prime &= y\cos{\theta} - z\sin{\theta}\\
z^\prime &= y\sin{\theta} + z\cos{\theta}
\end{aligned}
$$

Around the y-axis
$$
\begin{aligned}
x^\prime &= x\cos{\theta} - z\sin{\theta}\\
y^\prime &= y\\
z^\prime &= x\sin{\theta} + z\cos{\theta}
\end{aligned}
$$

Around the z-axis
$$
\begin{aligned}
x^\prime &= x\cos{\theta} - y\sin{\theta}\\
y^\prime &= x\sin{\theta} + y\cos{\theta}\\
z^\prime &= z
\end{aligned}
$$

Note: the first two nodes in each of the rotation setups convert the degree input to radians, which is what the trig math nodes want.

And finally, here's a .blend file with all the above node groups.

Wow! This is amazing... useful and really fun to play around with too. It's like Xmas on Halloween, haha! You're a genius. Thank you for dedicating your time to make something so cool! I'm going to be twisting vectors around like a madman now.

@Mentalist Glad you like it!  But I'm no genius, I just love math!

Well, humble sir, I could never have put together something like this. So how about I phrase it as: Thanks for using your talent of math comprehension to share new possibilities with the rest of us! I'm really terrible with math unless I can see it in geometric relationships. I can't take an equation and translate it into something meaningful. So your node setups are like a wheelchair to someone who is mathematically unable to stand on two legs. Ironically though, seeing it as nodes makes more sense than as equations, so I might actually learn something about math from your constructions.

I was trying to consolidate your Rotation X, Rotation Y, and Rotation Z nodes into a single Rotation node with three sliders for X,Y,Z values. However somewhere in the process I seem to have screwed something up because when set at the default 0,0,0 values it is still causing a change in rotation. Would you mind taking a look at my .blend to see what I did wrong, and perhaps show me how these X,Y,Z values could be input through a single Group Node to match the format of the Translate and Scale ones? Thank you!

Never mind my last comment - I realized it's easier to just chain them one after another: X, Y, Z and then group those three groups into a single "Rotate" node.

How do you get the Group Input node to say XYX?Mine just says Vector and Value

@fabriced  It's in the [N] properties panel on the right when editing a group node.  You can set socket order, name, and mix/max values.

Thanks! So I just createX, Y and Z as inputs in the N panel, that's it?

Awesome break down. Thanks. However, I noticed that the translate part could be done easier with just a Vector Math node with lets you add two vectors. If you want your group to have individual x,y,z, to add to a vector, you can first combine the xyz into a vector (via CombineXYZ node) then use Vector Math node to add the two vectors. (or subtract them). It’s possible that the Vector Math node may have not existed at the time you wrote your solution.

wow...that's impressive!

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


text:
How do I avoid rendering glitches from overlapping faces?
For instance, here I have two cubes that are offset only on the x-axis. When I render them (using Blender's internal renderer), the overlapping faces interfere with each other and the result looks awful. A quick and easy solution would be to offset them by just a smidget, but is there another solution that allows faces to overlap and not exhibit this graphical glitch?

Renderers really hate overlapping faces; they don't do well with figuring out what materials/textures to give precedence to. As such, overlapping faces are a major concern.

@GiantCowFilms: What? This question was asked in May and that question was asked in December.

@El'endiaStarman Policy states that we should prioritize best content. The answers on the other post are better and it has more votes. I know it might seem a little unfair, but stack exchange is about building up a knowledge base, sometimes at the cost of giving someone the shorter end of the stick (quite frankly though, I sort of agree with you personally)

@GiantCowFilms: That's quite understandable, and there's a similar policy on at least one other site that I frequent. Was just weird to get that notification almost three years after I asked the question. :P

@El'endiaStarman The topic came up recently, as some people were trying to close the target question.

@GiantCowFilms: Ahh, I see. Well, I went ahead and finished the closure since the other question and its answers are definitely much better. :)

As a general rule of thumb you should never have overlapping faces as you'll almost always get the artifacts you're seeing.. You're better off removing the overlap.

Well, the short answer to your question...

"is there another solution that allows faces to overlap and not exhibit this graphical glitch?"

...is no.

The glitch you are seeing is called z-fighting, and it is essentially impossible to avoid where you have overlapping, coplanar faces.
From Wikipedia:

Z-fighting is a phenomenon in 3D rendering that occurs when two or more primitives have similar values in the z-buffer. It is particularly prevalent with coplanar polygons, where two faces occupy essentially the same space, with neither in front. Affected pixels are rendered with fragments from one polygon or the other arbitrarily, in a manner determined by the precision of the z-buffer.

Basically what is happening is when two coplanar faces occupy the exact same space Blender doesn't know which of the two faces to render.  The faces are "fighting" which one is closer to the camera.  So due to floating-point calculations in the distance to the camera (z-buffer), various points of the shared surface are rendered as one of the faces, and other parts are rendered as the other face.  This results in the strange, undesirable glitch you are witnessing.
So without actually moving one of the fighting faces (which you have excluded) there is no way to eliminate z-fighting.

I wouldn't mind as much hitting one face or the other randomly if they weren't shadowing each other. It hasn't happened to me yet, but it did occur in the asker's case. Was this fixed in a later version of Blender? Clipping the bouncing rays at some minuscule distance should do the trick.

@JanDvorak  No it wasn't fixed.  It probably never will be fixed either, it's probably the most famous glitch in 3D graphics and any software/renderer will experience it.  The only way to fix it is to not have overlapping faces.

Having near clip on bouncing rays should cut it, shouldn't it? Solid materials can also be fixed manually by culling backfaces (and intersecting transparent materials are nonphysical in any case.

In blender-internal renderer there is a material option 'Z Offset' you can use to force one material to render on-top of another even if the faces overlap. This works in the game engine too and is quite handy at times.

Is Z Offset only for Z-Transp materials? That's what the tooltip suggests. It's otherwise grayed-out.

One way to avoid this kind of overlap is to use the Boolean modifier. If you have two shapes that are overlapping, you can join them together into a single shape by selecting the Boolean modifier and selecting 'Operation: Union.' In the example you provided in the question, this will give you a single rectangular prism you can manipulate that will render as one smooth shape.

I don't think this works as you'd expect. Actually, the resulting render will be even worse, due to how the resulting mesh is constructed.


text:
Hide specific wire line
In this model using 2.70 with toon-rendering and freestyle some edges (circled in red in the image) are rendered that should not be rendered.

I am a old man came from very old blender, so please be specific!
How can i keep only these edges from rendering?

Are you using freestyle to render the edges? For freestyle you can mark specific edges to be rendered as lines.

Every object has edges, so yes i render edges (what does you mean?)! Yes, i have the feature "freestyle" activated. What do i have to do? Mark the vertices to select a line and press what?

Finally i got it now.

Every face have a direction, some faces had a wrong side, so i had to flip the faces.


text:
How to get a square brush in texture paint?
Is it possible in texture painting mode to change the shape of the brush from circle to square? I am using the anchored stroke. As it is, it uses a circle brush and fades the corners of the image texture making it hard for me to make carefully aligned brush strokes. Other strokes that I tried also do this.

You could use a square mask image

I tried mask images too seen no change if you have specific instructions to follow please provide an answer.

Blender paints within a circular brush, you can use an image like a stencil when painting to get different shaped brushes.
When you create a image to be used for a brush there are a few things you need to keep in mind. When you have a square image, blender's brush will only paint within it's circle and that circle will be contained within the image dimensions, in practice I would also leave a little margin inside that circle as well.

Anything in the red area will not show in blender's brush, while the green area can be considered a safe zone for brush shapes.
To create a square brush using gimp you can create a 100x100 image and fill it with white then resize the canvas to 200x200 and click the center button then export to png.
Draw the shape you want in white and leave the non-drawing part of the image as transparent and save it as a png. Then in blender create a new brush texture as an "Image or Movie" and select your brush image. The transparent parts show as black in the preview, unlike normal transparent texture previews. You can use multi-coloured images as brushes, the colours will be mixed with the active brush colour based on the blend mode, so white will maintain the brush colours while other colours will tint the brush accordingly. Feel free to experiment with different alpha values for soft edges.

Texture masks work in a similar way but they don't mix colours like a texture brush, any colour info will only be used as a greyscale mask for the brush.
To get a crisp edge you will want to give the brush a sharp curve, this can easily be set by clicking the square preset button at the end.

Only want to add that instead of going out of blender, you can set up a new scene with a top down camera in orthographic mode and render a cube set to shadeless material. I also recommend using images that are closer to 1024x1024.


text:
What is a Point Density texture?
I see Blender 2.76 now has a feature called "Point Density" textures. Is this a particle system? If so, how is it different from previous particle systems?

Point Density Textures are a way of rendering particles or mesh vertices as volumetric halos in Cycles.
A halo is basically a little volumetric ball.  You can accomplish essentially the same effect without point clouds by using dupliverts or a particle system with little spheres as particles.  However point density textures are much more efficient due to requiring a much simpler BVH, since the entire volume is within one object, instead of hundreds of thousands of little overlapping objects.

The above example uses a particle system with 250,000 particles and a turbulence force field.  To render it as a point cloud I created a "domain" object (a scaled cube) around the particle system and gave it a volumetric emission shader using the Density from the Point Density as the emission strength.  See this answer for how to set up a point density texture.

Basically, it is a way of using particles or a mesh's vertices to drive the density of a volumetric material. You will need to use a Point Density texture and set the emitter object/mesh.

See more on the manual page


text:
X-ray material based on inner object's position?
I have an object:

That object has an object inside of it:

I'd like to get a map on the cube, based on where the internal object is in relation to the camera, such that I can make it transparent where needed to make the inside object visible:

This is going to be animated, so can't be a static map.
My use case is to reduce to IOR in the following brain object such that it's easier to see the red internal object:

You could split it up into different render layers, then blur an alpha mask of the "red stuff" that can be used to increase the transparency of that region of the brain smoothly.

You could also add an object to a mask layer in the brain's render layer that is tracked to the camera (it would have to be in front of the brain). This would not be as good though, as it couldn't be faded.

I fear it's going to be tricky to get the effect looking good in the compositor. Was hoping that I could get a map on the brain object that is a projection of the red object onto the camera.. would then still need to be blurred of course. Guess I could bake it.

You can also look into dynamic paint if you are fine baking it, but you still want it to be animated.

The mathematical approach would be to test if the camera's projection of the sampled point on the outer mesh overlaps with an approximated (i.e. spherical) projection of the inner object.  (That's not really a good explanation, I'll see if I can set up a working version tomorrow if you don't get a better solution by then.)

@PGmath that definitely sounds like what I'm after!

Do you need the effect to be seen by reflections too, or just the camera directly?

Camera directly would suffice for this.

Here is the result of my mathematical approach:

And the nodes for the outer object:

The value nodes on the far left are driven by the positions of the target (inner) object (top three) and camera (bottom three).
And here are the contents of the Norm node group, which returns the norm (i.e. magnitude) of the input vector:

The basic idea of my approach is to take the ray vector (from the camera to the sampled point on the mesh) and extend it to the inner object, then test how far this extended ray vector is away from the center of the inner object and use that information to adjust the outer object accordingly.  (In my example I reduced the IOR and made the glass lighter to make the inner object more visible.)
See below for a more thorough look at the math.
The only downside here is that the "hole" in the outer mesh will not be the exact shape of the inner object since I am basically approximating the inner object to be a sphere.
And here's the .blend:

The Math
Note, this answer is already fairly long and defining all the mathematical terms and concepts I am using here would make it much longer.  So to understand this section you should have decent precalculus grasp of vector math.  If you don't understand this part fully you can still just copy my nodes, or feel free to open a chat room with me and I would be more than happy to explain whatever you want.

Call the camera's position $\vec{C} = (Cx,Cy,Cz)$.
Call the center of the target (inner) object $\vec{T} = (Tx,Ty,Tz)$.
Call the sampled point on the outer object $\vec{P} = (Px,Py,Pz)$.
Call the radius of the inner object $R$.
The vector of the incoming ray is $\vec{CP}$, for simplicity I will call it $\vec{r}$.

The idea now is to determine if $\vec{r}$ is aiming towards the inner object.  To do this, normalize $\vec{r}$ and multiply it by the norm of $\vec{CT}$.  This will result in a new vector $\vec{r}^{\,\prime}$ in the same direction as $\vec{r}$ and length as $\vec{CT}$.

The last step is to determine if $\vec{r}^{\,\prime}$ intersects the inner object. This is pretty simple, just take the difference $\vec{r}^{\,\prime}-\vec{CT}$ to make a new vector $\vec{D}$.

This gives the final formula for the distance to compare to $R$:
$$
\left\vert\left\vert \vec{D} \right\vert\right\vert = \left\vert\left\vert \frac{\vec{r}}{\left\vert\left\vert \vec{r} \right\vert\right\vert} - \vec{CT} \right\vert\right\vert
$$
The node layout is just this formula, then sent through an RGB Curves node to tweak the falloff (the Add node right after the RGB Curves adds 0, it's purpose is to clamp the value to $[0,1]$), then used to mix the two glass shaders.  The Less Than math node at the very bottom compares the norms of $\vec{CT}$ and $\vec{r}$ (not $\vec{r}^{\,\prime}$) to apply the effect only in front of the target object.
Ping me in chat if you have any questions about the nodes or the math, I'm happy to explain further there if needed!

Cool! Can you think of a way to disable the effect out the back of the outer object? It's a little tricky, because there can be backfacing faces before the inner object, due to the foldy nature of my brain object.

@ajwood  I finally finished an explanation of the math if you are interested, and I included a .blend in case you haven't already taken the time to copy my node spaghetti from the screenshot (I should have done that in the first place).

Love the explanation! With I could upvote again :)

A (not perfect) solution is to use an UV project modifier.

Above :

1/ The scene setup. The camera location is guided by the sphere on left (not mandatory, see below). The camera points to the little sphere inside the cube
2/ What is seen through the camera
3/ The 'UV project' modifier setup. It is set on the cube
4/ Drivers to handle the scales in 3 (one driver per scale X and Y)
5/ The material setup
6/ A texture used to make "the hole" inside the cube, so that the inner sphere is visible

How it works :

The UV project modifier is based on an additional UV map created for it (called 'seeThrough')
The camera point to the cube, looking at the inner sphere. And the camera is used to project the UVs. So these UVs conforms to this projection
The drivers are here to handle the scale, so that the hole size stays constant, even if the camera moves. They calculate the distance between the camera and cube (or between camera and inner sphere if you feel it better)
The UV project modifier uses a texture (in 6) and maps the projected UVs to it
So in the Cycle node setup (5), we can rely on the texture color (black and white) to mix between the cube shader and transparency
Depending on the texture, the hole will be more or less clear/blury, and the hole size can be tuned using the drivers

The camera constraints are the following :

Copy location of the little sphere used to handle easily the camera (not mandatory)
Damped track to the inner sphere

Here is the result :

What is not perfect (at least that) is the hole is also visible on the back side of the cube. But as we see through the camera, this does not appears.

What's the purpose of transparency.png in the UV Projection?

@ajwood, you mean the other image files in the blend ? they were for test purpose. If you mean the texture, itself (whatever it is), this is to oriented where the hole will be. The UV project keeps the center of the texture projected from where is the camera as the camera is used to project it

so the UV Project modifier doesn't need an image and Override Image checked?

@ajwood, I think this is needed : we want this image (with its color) to be projected so that it can be used in the mix shader node. Without this 'visible' image, that does not work (or there is something I am missing)

Note : this is not sure to be what you really need (even if I think this is close to). Maybe someone else will give a more accurate solution (I dont know)...

@ajwood, Oh... was it clear that all that affects the UV map positions ?

I think this gets quite close to what I need, but I'm still experimenting. Will let you know if it turns out to work for me.

@ajwood, I wont be there for the next steps (away from BSE for some weeks), but you should upload a more specific shape in your question so that others can help you more

I learned a new technique here, so thanks! Unfortunately UV Projection turned out being really expensive on my big brain mesh..


text:
How do I flatten a selection of a terrain map?
How would I make this selection flat and later modify its elevation? The elevation map is represented in 3 dimensions and is a high-poly, computationally generated product of dronedeploy.

For the 2nd part of your question, please add to your question an example of your elevation map data. It might be directly usable (if it's a grayscale displacement map where color value corresponds with height), or might need some scripted conversion.

To flatten a part of your mesh:

Go to edit mode.
Select the bits you want to flatten.
Change the pivot point to "Active Element" through the pivot point menu.

Deselect and reselect an element (vertex/edge/face) that represents the height for your flattened selected. This will set this element as the active element. The entire mesh will be flattened to this height.
Scale to 0 on the Z axis via: S-->Z-->0.

That's it!


text:
Objects disappear when zooming in in perspective view?
When I am in my camera view, I can see my scene objects fine. But when I go to the user perspective and zoom in on those objects, they disappear. How can I fix this?

Related - http://blender.stackexchange.com/questions/8553/why-does-part-of-my-model-disappear-when-i-zoom-in-on-it-in-the-3d-viewport. The camera has its own clipping values which probably are good enough in order to preview objects as expected. When you leave camera mode, clipping values of 3D Viewport are taken into account.

The op is not in camera view, you have to lower your clip settings in the N panel View tab of the 3dview

You're right i misread the question and edit it


text:
How do I apply a texture to an object in Cycles with nodes?
I know nothing about nodes, so I tried to use them. I UV-ed my monkey head, and then I colored on it. I brought the image back into Blender, added a new material, then went to the node editor and opened the image. The image shows the two original nodes that were there. How do I set it up and get the image on to the monkey?

You are in the Compositing node view right now which is for post-processing.  You need to switch to Material nodes to edit your object's material.  To switch to material nodes click on the material icon at the bottom of the node editor.

Now you can add your texture with an Image Texture node and plug it into whatever shader[s] you are using.


text:
Replace image/texture option not available?
I'm watching a tutorial on how to make Minecraft animations, and one step was to click on the replace a image button but it wouldn't let me.

Why is this option grayed out?

Welcome to the site, David. You might edit your post to include a link to the video tutorial you were following, and post a copy of your blend file to Blend-Exchange which would provide those who wish to help more information about the situation.


text:
How to place a .png texture with transparency over a material
I am trying to create a low poly face with a face from a .png file. The issue is I already have material placed for hair and skin, as shown in the picture below.
I have created a .png file with a face which I would like to overlay over the skin material on the front of the head.

All examples I searched so far assume I also want the color of the material from the .png texture.
Update:
I added UVMapping, changed view to texture, made sure one face is on the eye but nothing is displayed..... see image... I don't know what is going on.

It will likely be easiest for everyone if you upload a copy of your ~.blend file to a hosting source, or to  [http://blend-exchange.giantcowfilms.com/], and add a link to your question so that those who want to help are working with you from the same material..

There will be no textures displayed in Cycles both in viewport and render unless you add Texture coordinates node, see this answer for more info.

The image texture node has two outputs, the color data and the alpha (transparency channel) data of the image.  The color data only holds the red, green, and blue of each pixel.  So if you plug it into a shader's color you will probably just get black where there is supposed to to transparency because those pixels are really black, but invisible.  You need to use the alpha output as a mask for placing the face over the skin shader.
To do this take whatever shaders you are using for the blank skin and mix them with a diffuse (or whatever other shader[s] you want for the facial features) based on the alpha output of the image texture.

Absolutely perfect!  Thank you for posting.

Perfect solution, but what do you mean by "those pixels are really black", I also found the transparent part is black in R/G/B channel, but why it become black

@user3505400 Every pixel has to have some value in each of the RGBA channels, even if the alpha channel for some pixel has a value saying that the pixel is completely transparent. Adobe Photoshop happens to export PNG files (and perhaps other formats) as completely black in RGB wherever there are completely transparent pixels. This is usually not an issue. (There can be an issue if you have something like a white object that fades out in transparency, and so you have pure-white semivisible pixel next to a pure-black invisible pixel. If a 3D engine has to interpolate between these two...)

You also can mix the texture with the material (using a single shader, mixing colors) this way:

Nice painting job @Bithur :). This reminds me xbox 360 avatars style.

@Gonzou avatar? thought is was photorealistic!

I looked closer (zoomed in the image) and have to admit you're right. IT IS PHOTOREALISTIC ;).

One way to do this is adding to the material a image texture, mapping "object", alpha premultiplied, mapped to an empty. The image sticks to the mesh surface facing the Z axis of the empty. If you move, rotate scale the empty, the image get the same transform. You can see the effect only in render, so maybe activate also "render preview" in a 3D view.
See this CGCookie tutorial for an example of this method.


text:
how are the math node operations in cycles calculated?
How does the math node do calculations with a specific operation:

the usual operations of add,subtract, multiply and divide are quite understandable and are(empirically) very similar to some of the operations in MixRGB node. But, how do the operations such as Sine, Power, Logarithm, Minimum, Maximum, Modulo, Round, etc,.. interpret with the values. How can we visualize this in realtime?

do you want to see the math behind them or visualize them

actually both, so the output would be much more predictable.

Here is a list of the mathematical equivalents of each operation.

Add: Out = Value1 + Value2.
Subtract: Out = Value1 - Value2.
Multiply: Out = Value1 * Value2.
Divide: Out = Value1 / Value2.
Sine: Out = Sin(Value1).†
Cosine: Out = Cos(Value1).†
Tangent: Out = Tan(Value1).†
Arcsin: Out = Sin⁻¹(Value1).†
Arccosine: Out = Cos⁻¹(Value1).†
Arctangent: Out = Tan⁻¹(Value1).†
Power: Out = Value1 ^ Value2.
Logarithm: Out = log(Value2, Value1).††
Minimum: Out = Smaller Value of (Value1, Value2).
Maximum: Out = larger value of (Value1, Value2).
Round: Out = Value1 rounded to nearest integer.
Less Than: Out = 1 if Value1 < Value2, else 0'
Greater Than: Out = 1 if Value1 > Value2, else 0'
Modulo: Out = Value1 (mod Value2).‡

Note that some operations use only the first input, in such cases the second input is ignored completely.
†. All trigonometric functions use radians.
††. log(x, y) = the logarithm of x to the base y.
‡. x mod y = the remainder when x is divided by y.

Is the second input value useless for trigonometric functions?

@bzal Yes, see edit.

what is the clamp for?

clamp keeps the result between 0 and 1

It doesn't work, for example Cosine with a value of 90 should give me 0 I have tried with a translate node with X at 0, I have attached the node and the image moves (more visible with a multiply node in between).

@DanylBekhoucha as the footnote mentions all trig functions use radians, not degrees.

Thank you for your answer. Yes I had found my error already, I have used it to create an emboss filter with a degree parameter: https://blender.stackexchange.com/a/102727/23134

To supplement PGmath's answer:
It is worth noting that the math is calculated a bit differently than you might think. It has to do with limitations of storing and representing floating point numbers (reals) in a computer (in binary format).
For the same reasons you cannot represent 1/3 in decimal exactly (it is 0.333...) you cannot represent exactly (for example) 1/10 in binary (but it is easy in decimal as 0.1).

The decimal floating-point numbers you enter are only approximated by the binary floating-point numbers actually stored in the machine.

This can result in some surprises. You can see what the number stored in machine actually is like this in a Python Console:
from decimal import Decimal
Decimal(2.675) = 2.67499999999999982236431605997495353221893310546875

So when rounding this number to 2 decimal places it will result in 2.67 instead of 2.68 you expect.
When building large nets of Math Nodes such "errors" can lead to a butterfly effect causing big differences in the end on the output.


text:
Why do 360° videos look low res when uploaded to Youtube?
I've been in the process of making a 1min 360° video for YouTube. I had already run some tests to make sure I knew how to make it 360° from blender to its final delivery, so getting it panoramic is no problem.
I've running some tests just to check the video quality is alright but it seems no matter what I do it comes out looking low res once uploaded to YouTube. I've used several templates for rending from online users and I've tried it in 720p, 1080p, and 1440p but it always comes out looking poor once I've got it uploaded. My normal animation I can export looking just fine. Where do you think I might be going wrong?

Related: http://blender.stackexchange.com/a/48188/2843

The youtube player only displays only a small portion of your video at a time (so you can pan around). Hence, only a small portion of the total resolution is used at one time. There's not much you can do except provide even more resolution, but I'm not sure if youtube even supports 360 videos at, say, QHD resolution..

But other folk don't seem to have my problem too bad, this one for example seems to have acceptable resolution: https://www.youtube.com/watch?v=lx4xyMn7sCQ

Have you made sure that you set it to the highest resolution when viewing on Youtube?

Yeah I always put it to HD and highest. Still nay good :(

You need to render it in 4k resolution to get a 1080p quality in 360 view

This has been driving me nuts too, haven't come up with a fix yet and I'm outputting using Premier Pro: unsharp mask, color correction, 4k resolution, ~30bps bitrate and 59.94 fps.  Looks great on my computer, then uploads to YouTube like garbage.
Even 1080p/60fps renders terribly on YouTube and you would think this would be their default 'let's make this look as good as possible' configuration they'd want to get right in-terms of their compression.
Johnpbuck submitted a video that looks decent I guess, but in my mind it's not a real world example.  Here's the quality I'm trying to get to without buying new cameras (which I don't think will solve the problem considering how good my cameras perform BEFORE YouTube) - https://www.youtube.com/watch?v=LByJ9Q6Lddo
The only trick I can suggest that others may not have tried yet is forcing rendering of your video at 59.94fps.  My cameras don't go that high but YouTube does grant a higher bitrate during uploading to a frame rate beyond 30.

If you're not sure you can answer the question, comments section would perhaps be better. :)

True, sorry just venting about my render/upload frustrations.  My 'fix' is waiting on YouTube to up their game, which will happen, it's just a question of when.  If Vimeo could jump in and start supporting 360° video it would be a huge game-changer.

It's okay, just keep it in mind next time, and don't worry, if you ever get called out for doing something wrong, it's never personal, and happens to pretty much everyone at first.


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Textures are shifted in Cycles render
When I try rendering my model in Cycles, it warps the textures for whatever reason - here is an picture to demonstrate:

The windows should look the way they are on the right in the 3D view. What is be causing this?

I guess something in some mapping setting could be using wrong coordinates... difficult to say what exactly is wrong, without seeing settings or having a file...

You may want to upload the file. Also, do you have a subdivision surface modifier for example with a render value different to the view value? This may be causing your problems.

@m.ardito Good to mention where they can upload their file, e.g. here: http://blend-exchange.giantcowfilms.com/ particularly as they are a new user.

It looks like you have already unwrapped your model, so I am guessing that the problem is that Cycles isn't using the UV map you have created.
To tell Cycles explicitly to use a particular UV map add an Input > UV Map node and plug it into the Vector input on your image texture.  Make sure that the correct UV map is selected on the UV map node.

Alternatively, you can check which UV map is being used as the default UV map under Object Data properties panel > UV Maps rollout.  You can set the default UV map by clicking on the small camera icon next to it.

This will only have an effect if there are no mapping coordinates explicitly defined for a texture as above.


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Finished AVI file wont open!
(I have newest version of mac and blender) I finished rendering my intro template after about 30 mins. The rectangle where it was rendering went black. I went to my downloads where I had saved it there was a quicktime file that I opened and said "converting....... QuickTime Player can't open "blender finished intro0001-0220.avi" To see if additional software is available that will enable QuickTime Player to open the movie, click Tell Me More. when I did i brought me to the apple website and said I had to download quicktime 7 even though i already have 10.6 I think. I followed the instructions and downloaded it but the file still wont open.

If an error happened before blender finished all the frames that were supposed to be rendered, I am afraid the .avi file may be corrupt. It cannot be opened or fixed. The way to render an animation the safe way is to always render as an image sequence. Meaning render each frame as a .jpg or .png file format. You would then use the VSE (Video Sequence Editor) in blender to combine all the images and save it as a .mov or .avi movie file format.
This way if some error occurs you can still restart the rendered at the point where the error occurred, instead of starting all over again because your movie file was corrupted by the incomplete rendering process.
That is how the animation industry does rendering work at a professional level too. This workflow allow for post production work, like adding visual effects and color correction after the all the frames are rendered.


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Cycles Procedural Texture Study
I've become very interested in procedural textures as of recently. I would like to start building my own library of these textures, so I can easily texture scenes without having to search for copyright free materials to use online.
So far I have successfully recreated two procedural textures, marble and brushed metal, and was even able to come up with a brick texture by myself. It's not up to its full potential yet but I am happy with it.
Anyway, I would really like to keep learning how to make different procedural textures, and was hoping to find some guidance here. If you guys have any experience with this and are willing to give me examples of how to make different textures I would highly appreciate it.
(Just wanted to say that I don't want to copy your node tree to the letter, I would just use them as an example/guidance!)
As of now, I have: Marble, Brushed Metal, and Brick already.
I am looking to learn how to make: skin, leather, dirt, stone, cracked stone,  reptile skin, tree bark, everything really.
I feel like by recreating and playing with the examples you show me I will be able to figure out the "pattern" I am not getting when it comes to creating a procedural texture.
Here are the images of the textures I have done so far.

Oh, also any guides and tutorials on the subject are highly appreciated as well! Books and websites with the topic too!
I really appreciate it!
M

I'd definitely recommend this talk on manipulating texture coordinates

Thank you Gandalf3! I'm halfway through it, its really cool stuff. Can't wait to put it into practice. Thanks again!


text:
Automatic weights deforming my character rig
I'm making my second rig, and I'm having problems when I want to set the mesh as the armature parent. Once I press Ctrl+P to open the menu and select "With automatic weights" it deforms the mesh.
I have looked on several pages and done everything they said, setting Roll option to 0, or setting the pole angle to 0 to align all the bones.
What else can I do?

Thanks.

Can you give us a picture? Could help a lot :) before and after the automatic weights

Can you put a download link of your blender project? I realized the problem but not so sure. i want to check it

Sure, here is: https://www.dropbox.com/s/53synifdr10e088/Model1.blend?dl=0

You have got multiple problem with your model.

Your Character's head has half an extra meshes with the mirror modifier.
I select the extra vertices and deleted them.
You have overlapping faces on within the model.
I removed the extra faces with W key, then select "remove double"
The body of your character have normals facing in the opposite direction.
I corrected the the normals with CtrlN.

Here is the blend file after I corrected those issues. The weights are now correctly applied.

Extra note
I must say I have noticed that your have rigged the hand IK object to the hand bone. Shouldn't it be on the lower arm bone, you might have to get a better tutorial on the subject. Your bone objects are not rotated to the correct front facing position at rest. Always check your bone orientation with it's local axis turned on.
Here is the improved rig.

Thank you very much. Can you give me indications on how do you manage to solve the issues?

I have build on my answer. You may want to read the Extra note.


text:
What algorithm does Blender's motion tracking use?
I would like to know what kind of algorithm Blender uses in motion tracking?


text:
Minecraft Render Blank Spaces
I'm using Tomy's Minecraft Render for my minecraft skin render. Why do the arms have holes at the end of them?

Try flipping your normals on those faces in edit mode. You may just want to do a select all and a recalculate under the UV tools. Or you could just make your mesh objects Double Sided.


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How to flip camera view?
There is a hotkey mentioned by Gleb in the Blender Guru podcast that allows the camera view to be flipped on the x/y axis, I can't remember it for the world, nor find it anywhere in google.  The episode is like 3hs long so I'd prefer not to go through it again trying to find the moment he mentions it.  What is this hotkey?

Is this for rendering or preview?

that's a dulipcate of http://blender.stackexchange.com/questions/26208/how-to-flip-the-view-from-the-camera-horizontally

3D  view/Render
Give the camera a negative scale on the local X axis.
Both S X X -1 and ⎈ CtrlM X do this (use Y instead of X for flipping vertically), or you can set the scale directly in the transform panel:

Rendered animation playback
When previewing an already-rendered animation (⎈ CtrlF11) you can flip the display horizontally with F and vertically with Shift-F.
Sequencer
The VSE has an option to flip strips in Properties region > Filter:

Thanks ideasman42 for mentioning these :)

well that's another way of doing it. I've just found the hotkey i was mentioning, Ctrl + M and then pressing the x or the y key. thanks

I accidentally reduced my scale below ZERO and was so confused until I found this post. Thank you!


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Why does the math node change the noise texture's color output to B/W?
Could someone please tell me why plugging a color into a math node (in this case set to subtract) makes the output black and white?

This is because the math node only deals with single scalar values (note the gray sockets).
See What is the meaning of the color of the node sockets in the node editor?
If you use a node with yellow sockets (Color > MixRGB), it will maintain all the color channels:


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No Option for Smooth/Flat Shading
I'm trying to create some objects in blender and I just installed it, but for some reason I have no option for smooth/flat shading in the tools? Im new to blender so I dont know where else to find it.
Any help is greatly appreciated

@cegaton, shading options should be available in Object Mode also (in Edit panel).

It looks to me like the object is not your primary selection. Try pressing "A" to deselect everything than right click the sphere to make it the "active" selection. Active selections usually have a brighter border yours does not look like the active selection.

@David Prentice No matter how many objects are selected you should still have this option visible in a Tool Shelf. Also with multiple objects selected you can apply shading type to all of them, so your solution isn't right.

@Densino what Blender version are you using?

In 2.76 even with nothing selected I have below 'delete'  Join, Set Origin, shading -smooth flat, data transfer.

thank you guys..I sorted it,. the object just wasn't selected. my bad

If the active object isn't a mesh, curve, or surface these options won't be available (thanks @Carlo).
Right click on an object to make it active. Use ⇧ Shift RMB to make an object active while maintaining the rest of the selection.
It's somewhat rare that you end up completely without an active object, but it can happen e.g. when switching between layers.

I would add that the active object must be "shadable" (e.g. cameras, empties...are not).

In short, you need to unselect everything by pressing a and then right-click the sphere. Then you'll have shading options.
The long answer is: Blender does a weird thing with "active" versus "selected" that I haven't seen done anywhere else. It's not complicated, but it's hard to figure out if you don't know what's going on. The dark orange outline means that the sphere is "selected" but not "active." Multiple things can be highlighted at once, but only one of them is "active." The "active" one will have a bright orange outline. The "active" one is the one whose properties will be showing in the properties panel, and whose name will be in the bottom left of the screen. For actions that can't be applied to all the highlighted objects, that action will be applied to the one object that is "active."
If you have many objects highlighted, you can change which one is active by holding shift and right-clicking different objects. If you right-click a "selected" object, it will become the "active" object. If you right-click the same object again, it will usually unselect it, and it won't be highlighted at all anymore. At this point, there will be no "active" object.
When you press a to unselect, it doesn't change the active object. So if you unselect with a and reselect with a again, you STILL won't have an active object.
Hope that helps!


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What are the node plugs called?
To help me communicate better what is the correct name for node attachment points?

Sockets
In the Blender manual's page about Node parts it is said that Sockets is the name for the ...

...input and output values from the node.
They appear as little colored circles on either side of the node. [...].
Each socket is color-coded depending on what type of data it handles.

If you are interested in color-data relationship, see related question What is the meaning of the color of the node sockets in the node editor?

authors: محمد شهاب الدين


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How do I Make a Transparency to Decal my Object? (Blender Render Only)
I can't find an answer to this question. I want to make a decal and add it on top of another texture I've already applied to my object (I can redo it if necessary).
I don't have the decals yet because I still have to make them, but I don't know how. I know that the background has to have something done to it to make it transparent, and I know that Blender has to handle the file as a transparency by adjusting the alpha channel, but that's all I know.
Can someone who has the time please step me through this and make it simple to learn? Maybe an example file that I can study?
Thanks in advance.

this looks like a duplicate of Alpha transparency making wall transparent, let me know if it helped.

All you have to do really is save your texture in an image format that supports transparency. Any with alpha channels should do like PNG, TGA, TIFF, or any other supported by Blender.
You can use any image editing software like GIMP, or Krita, or Photoshop to remove the background of your image and make your decal texture.
Then in Blender add a new texture to your material
Under the Properties Window > Texture Tab > Image Mapping change the Extension mode to Clipping
Under the Mapping panel Change the Coordinates type to Object and bellow pick any object in your scene to control the position of your decal.
You may create an Empty type of object specifically for this, then use it to control the position of the decal, move it about, scale it to set the size, and rotate it to match the surface normal.
Have in mind that this will only work in the rendered view, viewport preview is not supported.
Example file

How about a sample file? Words help to a point, but a real example would be far better.

There you go, blend file added

The file is completely empty.

Weird, I'll check later today when I am back at the computer.

What do you mean file is empty? Just downloaded it and there's a demo icosphere with a decal texture applied with the technique described above. Try downloading it again, see if you somehow got a corrupt download

It's still the same. I get a bunch of empty windows that are set up so that getting out is difficult unless you know how to get the file menu up afgain. There's an Outliner showing an empty and a constraint, but they don't show up in the main window. The other windows are blank.

Open Blender without any file, then go to File > Open and untick the option"load UI" from the bottom left of the screen, then browse to and open the downloaded file. Anyway you don't need it, you should be able to do it easily from the above provided instructions

I don't need it like people don't need clear instructions.


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Is there a shortcut to keyframe an entire skeleton?
I'm new to animation in blender and I'm trying to make some character animations for UE4. I was wondering if it were possible to keyframe every bone at once instead of having to hit 'I' over rotation for every bone in a new pose? It sure would save a lot of time.

In the timeline, activate the red record button to automatically insert a new keyframe every time you move a bone, and the "two keys icon" aside to use the selected option for keyframing; then select from the menu the "whole character" option to  keyframe all the bones of the character everytime you hit the "I" key.

In pose mode for the armature select all bones with the keystroke
[a]
then keystroke [i].  The menu will appear and you may choose the keyframe attributes.


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Blender recalculate Vertex Position so no Group Transform Matrices are needed
I have a Model (I'm sorry I can't upload or show images of that). This Model is a huge bunch of group nodes and geometries and so on.
Some of the group have their own transform matrices and some are identity. This is normaly just fine and how it should be. I know that. But for my problem I need the model only to have ONE (or none) transform matrices in the head node and every other group node should have identity matrices. Is there a way to recalculate every vertex of the model and set all matrices to identity? So all vertex share the same "local space".
It would be super cool if there is something like that in Blender and somebody could explain how to do that.
Maybe this helps:
Model
- Group One Translation -2 0 0
  - Geometry Vertex 1 0 0
- Group Two Translation 5 0 0
  - Geometry Vertex 4 0 0

this should be converted to
Model
- Group One Translation 0 0 0
  - Geometry Vertex -1 0 0
- Group Two Translation 0 0 0
  - Geometry Vertex 9 0 0

Hi Noxxer (or NoxxKn?) welcome to Blender SE.  Blender's usual data structures aren't really represented by nodes, unless you're using something like Sverchok to model them parametrically.  Assuming you're not using nodes this way, I suspect you're looking at merging a number of different objects mesh objects into a single object, with one object transform(giving each vertex an identity relative to that origin).  Is this the case?

Sry i come from the programing side. xD
We call the structure of model a tree with nodes ... sry for that. : )
No the structure of the model should remain as it is. Only the coordinate systems of the whole model should be one.
I have updated the question so it is more visible
Greets NoxxKn

No don't be sorry, even other 3d packages call it nodes.  If you want each object to recognize the same ultimate matrix without having to merge them, you need to parent them:https://wiki.blender.org/index.php/Doc:2.4/Manual/Modeling/Objects/Groups_and_Parenting

Blender always has to have geometry wrapped in an Object datablock.  So the best way to achieve your Group X >> Geometry xx zeroed out is to parent Geometry xx to Group X Object, and then do an Apply location to Group X.  Without seeing a blend or a screenshot, I can't be anymore specific.

Thank you for your your reply. It was very kind of you. With the information i gave, you did what you could. I will try that and will mark the answer as the right one if it has worked. : )

No problem Noxxer, glad to help.


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Blender VSE cropping a video
I am doing a full screen recording of my macbook pro at resolution 2880x1800. The actual content area of the screen that I would like to record is only about 2326x1380 pixels, that's an awkward number I know but there's a reason for it. I would like to use blender vse to crop this video down to a 16x9 aspect ratio so that was the closest 16x9 aspect ratio that I could crop out of the recorded area while getting everything that I needed in the video frame.
inside blender vse I setup the video properties like this:

it's a 1:1 aspect ratio with the resolution set to the size of the video.
In the strip editor I add an image offset of -160 on the y position to get everything in frame.
this is a screengrab of part of the window:

As you can see there's still those's still pillow box black borders going on.
How can I change these settings to allow the full 16x9 aspect ratio w/o the borders?

That's because your actual screen ratio is 2880/1800 = 1,6. But your desired ratio of 16/9 is 1,7777 (periodic). This doesn't fit together. Blender (by default and there's no way to change that) does scale your input Video to fit into your Render Resolutions Aspect Ratio (I don't mean the Aspect Ratio Pixel size below the Resolution but the actual resulting ratio of your Resolution dividing width by height).
Because your ratio is off you'll get your black bars to the left and right because the rest is fit into the heigth of 1380 pixels which means that your original input should be 3200 pixels wide to fit into your 16:9 format. But as it isn't Blender aligns it horizontally centered and fills the remaining space with black color.
So you'd have to use the Image Crop function of your Strips Strip Input Properties panel in the VSE to precisely set the area that you'd like to cut off.

I noticed that, one more question. Is it possible to change the blender vse video preview window background color from black to another color?

Just add a color strip below and set your video strips blend type to overdrop or alpha over.


text:
What's the correct way to import animations with node bones
I am coding a Blender Ogre importer for Ogre 1.10. I want to import the animations from the .skeleton but ogre and Blender bones are different:
Ogre:

A bone is a Node
Have an offset from parent (translation)
Have a rotation (quaternion)
Have a scale

Blender:

Bones are a pair of 3D points: head and tail
Can be connected/disconnected from the parent tail
The offset is relative to parent tail.
The head-tail length can't be 0

Blender bones cause 2 issues:

I can't create bones if ogre bone is just a rotation relative to it's parent (because blender will delete the bone automatically)
I can't just create only "disconnected" bones because the offset is relative to the tail and the head tail length can't be 0...

My question is: How blender import node-based bones usually (in other formats) ?


text:
Is there any place where I can find .blend files of car interior parts
I want to know website where I can find 3D .blend interior car parts like steering wheels etc.
Please answer as soon as possible. I need this urgently for my fyp project.

See http://blender.stackexchange.com/q/15355/599

The OpelGT by Rogper would be the most detailed car you will find, the engine would be the only thing not modelled.

Blendswap.com contains lots of free Blender models. You can find there some car parts too. E.g. http://www.blendswap.com/blends/tagged/car

well I just checked there.. and they are only providing tires and rims.. I need internal parts like steering wheels and gear console..


text:
How to make a food tray
How can I go about modeling a tray like this?

related: http://blender.stackexchange.com/questions/34372/how-to-model-a-plastic-food-tray

Start with a cube, go into edit mode (Tab) and scale it (S) to approximately the proportions you want.
Select and delete the top face (Del or X).
Go into Edge Select mode with Ctrl+Tab and select the bottom edge and 4 corners and bevel them with Ctrl+B, using the mouse wheel to control the number of cuts.

Select the top edge and extrude (E) it a couple of times to create the upper lip.

Add a Solidify modifier to give the tray some thickness, and a Subdivision Surface modifier to smooth it out.

Thanks a lot and sorry for my delay,


text:
Accidentally disabled transformation keys?
I was working in Edit mode, merging a series of vertices, when I accidentally hit an unintended key combination which I now, unfortunately, don't remember. Nothing obvious happened, so I carried on.
However, now I can't use the keyboard transformation commands R and S. The transformation handles are greyed out, and though the transformation values are reflected in the Rotate (or Scale) status panel, there is no effect on the object and no change in the Object Data panel.
What have I done? And how do I reverse it?
I've spent some time googling, but I'm lost in a huge mass of hotkey information, and not knowing just what I've done makes it difficult to form a useful query.

Could you show screenshot of the "transformation handles greyed out" ? Also in what mode transforms work no more - Object or Edit mode ? See Object not rotating or scaling in viewport

You probably inadvertently hit Alt+, (comma), this turns on Manipulate Center Points, also found near the middle of the 3D view footer.

This makes all transformations only manipulate the origins of the selected objects, so scaling and rotating only do anything if more than one object is selected.  To disable it just hit Alt+, again or click the button in the footer.

That was the problem precisely. Thanks — another thing learned :)

authors: Павел Соломенников


text:
How can I make my water not look like ink?
I'm working on a small creek including animated water (using a fluid domain). While I'm satisfied with the baked flowing animation of the water, I don't really like how it looks. Here's a render:

It's way too opaque (nontransparent), I would like to have a more cristal-clear type of water. I've cranked up the brightness of the sun, but as you see, that only increases the brightness of the reflection. I've tried using fill lights from different angles to brighten up the scene, which works to some extent, but the texture still looks like ink. So I'm looking for help on how to make it look more like clear water.
Here's my current texture:

What color do you want to see?  Brown earth?  Stylized blue water?  Please post an image of something that would be your goal.

I was going for a realistic look ... there's a reddish/brown stone texture on the bottom of the creek though

Please see.  http://blender.stackexchange.com/questions/64/how-can-i-create-a-water-material-in-cycles .  Where did you get your nodes depicted?  They are many realistic views in the world.

What kind of environment lighting do you have?

@atomicbezierslinger From a Youtube tutorial. However, it was focused on the fluid simulation rather than the texture, so it probably wasn't very elaborate ... Ok I tried building the material depicted in the accepted answer to the question you linked, but now my water is completely black °A° ... ?

@PGmath I have one sun directed coming from the opposite direction the camera is pointing to .. somewhere between dawn and midday, I guess. I will also add some area lights as fill lighting to soften the shadows

That's why your water looks like ink, you have no environment for it to reflect!  Try using an HDR IBL (image based lighting), Greg Zaal has some really good free ones.  Or try Andrew Price's Pro Lighting: Skies (it has a free version).

I think your problem is that you dont seem to have a sky etc to reflect.
You also need some more ambient light to illuminate the dark corners.

@PGmath Thank you! I don't really want to use assets from other people, but I have some regular high-resolution sky picture I took myself. They're not HDR images, but I'll play around with it a bit and see how far I get with that ...

This may or may not be of importance, but do you have the number of bounces set high enough (properties window -> render tab -> light paths panel)  Transparancy, Bounces, and Transmission values may affect your result.

Maybe im just too late right here, but anyways.
You need to mix a glass shader (put 1.35 IOR) with a transparent BSDF and you're done, or if you wanna go beyond and have a photorealistic water looking, you can do it by combining the Principled BSDF and transparent BSDF.
Change these settings on the Principled Shader:
Roughness to 0 or 0.05 (depending on the type of water, if dirty, clean, etc)
IOR to 1.35
Transparent to 1 or 0.9 if dirty and such (you can also play with the colour and the transparent bar to add some color to the water)


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Best output file format for 3D model to Unreal engine 4
I am creating models in Blender for a game in Unreal Engine 4.  What output file format is the best and I can use for this for commercial purposes?

I use Unity, another game engine. It does accept normal .Blend files. However, I'm not sure about Unreal engine. I would recommend .fbx as this is a sort of global file type for models like these.

Most people use FBX when exporting to UE4 – you'll find a lot of information over at the UE4 Wiki in the Blender Section
Personally the only issues I've dealt with myself are:

Importing meshes with millions of polygons (something you should not really do in a game engine anyway)
takes a few minutes.
Applying modifiers before exporting is a good idea as I've sometimes had some meshes in the .fbx missing when importing

There are also a few live-streams from UE4 that are archived on YouTube, for example: https://www.youtube.com/watch?v=KDP7GHFtAtE

The best output format is the one recommended by the game developer. There is nothing from the Blender foundation that would affect use for commercial purposes, but elements of the game may be covered by other intellectual property considerations. For example, it is possible that the game developer trademarked elements of the game which could be infringed by the content you create in Blender. Consulting the game developer would be the best source of info on what might, or might not be infringing.

So in theory I can use any file format when I does it.

Perhaps. Only the game developer knows for certain.

authors: ПИ - 231 Богдан Екатерина


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Is there a better way to extend a Bezier Curve?
It seems very tedious and therefore slow to extend Bezier curves while creating them in Blender. The docs say to select two control points and W > Subdivide. This makes extending the curve unreasonably difficult, since after adding an additional control point (which is where you need the new point to be) you must then manually move both the end point and the new point into their desired positions, adjusting their handles, etc.
When extending the curve, even moving the current end point to where you want the next point to be (prior to subdividing) is odd and difficult, requiring many adjustments after subdividing to get the new point. Is there a better way?

Create a bezeir curve.
In edit mode select a control point at the start or end of the curve.
You can press:

E to extrude (and move) a new connected point
Ctrl Left Mouse Click to create a new connected point.
To make new control points that are unconnected to the existing curve deselect any previously selected control points and press Ctrl Left Mouse Click
V to set handle type (vector straight, aligned, free, etc...)
New points are the same type of active (last selected) control point.
AltC to close a curve

For more info see the Manual


text:
Smoke hi-res fire artifacts in Cycles?
When rendering smoke/fire simulations with cycles I sometimes get some random lines/artifacts on my render. Do you have any idea what might be causing this?
There are also some issues with transparency, but luckily they are not too noticeable.

Here are my rendering settings:

I'm using 2.77 rc2 and tried both CPU/CUDA. I've had similar artifacts with previous versions and CPU rendering.
Edit:
I've discovered that the issue is caused by Smoke High Res:

Not using any compositing effects, are you?

Compositor is disabled here. Of course I found the culprit directly after posting :/

The issue is caused by Smoke High Res. It was fixed by applying the scale of the smoke domain (Ctrl+A)


text:
Fluid emission doesn't follow animated inflow object
I am animating some text (converted to a mesh) shake around in front of the camera. After that, I want it to turn into a fluid and fall away.  I tried going to the starting point of the mesh falling as a fluid (frame 86), and then made a giant, transparent cube for the domain and made the text mesh the inflow.  When I baked the fluid, all that happened was that that fluid started falling out from the starting point of the text in frame 1.
P.S. I am rendering with Cycles.
P.P.S. I would like the fluid to fall until frame 250.

Check out this tutorial on youtube. This person is does what it sounds like your asking. Your welcome Ice text tutorial (Fluid text)

The text mesh should not be a fluid inflow, but a fluid fluid (just change type from inflow to fluid). An inflow will keep producing liquid throughout the animation.
Now, if you bake this, you will see fluid start falling at frame 1. In order to start the fluid simulation at frame 86, go to the domain settings and set Offset to -86. You don't have to rebake to see the results.
Then all you have to do is to keyframe the visibility of the fluid object (the text) so that it is visible at frame 85, but not at frame 86. Because at that point, the fluid simulation takes over, so to speak.
However, what you will probably discover is that there is an obvious change taking place when switching from the text mesh to the fluid. One way to get around this is to set the resolution of the domain to something very large (greater than 800 at least).
The easier solution is to replace the text mesh with a mesh of the fluid as it looks in the first frame of the fluid animation. Just go the first frame where the fluid appears, then duplicate the fluid domain but leave it in the same place. Under Modifiers you will find the fluid sim. Apply the modifier. This will create a mesh of the fluid as it appears in that frame. Replace the text mesh with this one.

I thought that when you apply the fluid modifier the animation stops running and the object is now permanently the mesh of the current frame. Is that true?