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Plastic material for a dice
I'm working on a material for a dice. My first attempt below has a more velvet look:

Then I've downloaded a material from Blendswap with this outcome:

I like the top of the dice, but the rest is not OK. After finding a tutorial on how to create a glossy plastic the dice looks like this (I used the same red color for the diffuse and glossy shader):

I've used the same red color for the diffuse and glossy shader which results in a less plastic look. After changing the color of the glossy shader to white the dice looks like:

The top looks more plastic, but the rest is not quite what I want.
Question
How can I improve my material to get a 'realistic' plastic look for my dice? Below you can find a screen shot of my current setup:

After removing the relecting floor (and a little adjustment of the lighting and applying the material setup as above) I got the outcome shown below. I am sort of pleased with the plastic look but now I have lost my reflective floor ....and I don't like that. How to create an image with the plastic look and the reflective floor ??? Or would that be a Photoshop job ?

I am looking for a plastic material like this or this.
I'm a beginner and I'd appreciate a explanation or some instructions how to achieve this. Thanks.

it would help if you linked to a specific example of the kind of material effect you are looking for.

You can put on background HDRI and have a better look at your dice's material

Hows this? http://www.pasteall.org/pic/92044

Could you put your .blend file on BlendeExchange? http://blend-exchange.giantcowfilms.com/ We have this because hosting services like pasteall remove the .blends after a few months, and when something is put on dropbox, google drive, etc, it will usually get deleted later on to preserve space. The reason why this is important, is because StackExchange isn't supposed to just be here so that people can ask question and have them answered, it's a resource that people can look back at, and if something that was used to explain something, and it's missing a resource (,blend file) it's now useless.

So you want glossy surface, but you don't like the floor reflection in the dice? Get rid of the floor.

@ TARDIS Maker I added the file to Blend Exchange. Regarding your suggestion: yes, I like the top of your dice but the vertical faces are still a lighter color of red. If the vertical faces would be like the top face I would be very happy I think. I don't think this is because of the floor reflection. Can you upload your blend file too ?

@ TARDIS Maker I removed the floor and I guess the reason for the vertical faces being a "lighter red" is because of the floor. Could you upload your blend file because i believe your material is the right one.

@Jerryno Is it possible to create a render that don't has the floor reflections and still has a white floor ?? Or should I solve that in Photoshop ??

@JanScherders Sorry, I didn't get a notification for your comments (I'm pretty sure it won't notify me if there are spaces between TARDIS and Maker). Are you wanting it on a pure white background then? I could simply remove the floor, enable transparency, and then in post add a white background.

@TARDISMaker I would like that. Could you please upload the Blend file ? I don't quite understand what you mean with "enable transparency"

@TARDISMaker As I understand it you recommend to remove the floor and add it again in post. I did experiment (for instance with roughness and the mixed shader factor) but couldn't bring down the reflectiveness of the floor enough. Is there no way to keep the floor in the scene AND have no ugly reflections on the dice ?

Give me a little bit and I'll have an answer for you. You really shouldn't need the .blend file. I just used a custom fresnel node that I like to use, and got rid of your mesh lights. It's possible to have the floor in the scene and not reflect, but I wouldn't recommend it. It will just end up looking weird. The floor and the die wouldn't match up properly.

maybe the problem is the light bouncing from the floor to the dice.
-try to do it in blender render.
-put the floor in other layer(2).
-select the lamp.
-click the "this layer only".
-make sure that the dice and the lamp are in the same layer(1).
-select the two layer(1),layer(2).
-then render.......

I hope you realize that he's talking about rendering in cycles.

I think you were right !! The material I created did the job pretty well (although I would like the material a bit less glossy). But you were right ... the reflection of the floor caused the "light red" vertical faces.


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Reflective floor and glossy material
I am working on a dice. That dice is placed on a white reflective floor. The reflective floor has a big impact on the look of the dice:

After removing the reflective floor I got this:

Question:
Is it possible to add the reflective floor again and preserve the plastic look of the dice (so no floor reflections on the dice) ?? I work with cycles.
After reading the answer of Faceb I unchecked Glossy in Ray visibility. The result is in the image below. Now I have a dice with a nice plastic look and a floor reflecting the dice but not changing the look of the dice. But now I have this black line "surrounding" the dice. Now ... how to get rid of that ?

Jan, don't forget our brains are used to seeing reflections on objects, especially on specular objects. Seeing some form of reflection helps us get a sense of the surface property of an object. Once you remove the reflections and the surrounding it becomes less realistic. Additionally the phenomenon of 'colour bleeding'  can be observed by putting a very brightly coloured object on a white surface, like a carrot on a sheet of a4 paper.

I agree with you but for this image I do not mind that. I don't want the floor have an impact on the look of the dice

You could try the following:

Select the floor
Go to the Properties panel
From the tabs, go to Object (looks like a cube)
In Ray Visibility, click on Glossy check

source: Stack Exchange

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

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Rigify Generate -- Deformation Bones vs. Armature?
Why should I use deformation bones instead of just parenting w/ automatic weights straight to the armature? The octahedrals act as bones while adding keyframes... However would deformation bones possibly lessen the possibility of import export errors especially to UE4?

When you generate the rigify rig after adjusting the initial meta-rig and pressing generate in the armature tab (in the properties window), rigify genetates a host of control bones with ready made complex behaviors such as IK, foot roll, fist open/close, and many more.
If you're animating the deform bones directly, and ignoring all these features, you probably don't need to generate and can bind to the meta-rig directly.

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


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Joining text objects and cube
I have a cube and created Text objects on all sides of the cube. After converting the text objects in meshes this is the result:

After joining all text meshes and the cube (selected the cube as the last one) this is the result:

Question: What is happening here? Why is my "W" suddenly changed?

Related: Object reverts back to non-modified state after joining

The issue is, as @TARDIS Maker pointed out the sub surf modifier that you applied to the dice object. Its effects are being applied to the text. To rectify this you can add a mean crease to the text to prevent the sub surf from taking effect. Select the vertices that make up the text and use Shift-E then 1. This will make your text appear exactly as before (Unlike holding edges which will cause minor rounding) with the added benefit of not having to apply the modifier (Maintaining a non-destructive workflow).

It looks like your cube has a subserf modifier on it, so when you joined the two, the text inherited the subserf.
The active object (the object you selected last, even if you deselected it), is the object that the other objects get joined to, so those objects also inherit it's modifiers. If you had selected one of the text objects last (making it active), it would have removed the subserf from the cube.
What can you do to fix it?

You could apply the subserf before joining the cube and the text
You could adjust the text so that it's subserf friendly, by adding holding edges.
You could keep them separate. This might seem obvious, but depending on the object, it can sometimes be better to just keep the objects separate.
As GiantCowFilms mentioned, you can also use the mean crease. Usually I don't recommend using this because it can cause distortions if it's not used properly, but in this case it works perfectly fine.

yes, I the cube has a subserf modifier. I chose your solution 1 as I want to append the joined mesh in other blend files


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Odd, glitchy shadows (Blender Internal)
Uploaded an unlisted video of it on youtube, happens at 00:05.
If you notice, the shadow of the blue shirted guy's head is blocky and very glitchy. I have no idea what caused this. Here are my render settings:
24fps
AAing turned on at 8, full sample
256x256 tile size
PNG, 90% compression
720p 100%
I just need someone to explain this. Thanks.

If you mean these shadows, then it may be z-fighting. Take a look at this question or at this one

The blocky shadows are either caused by a low resolution shadow buffer or your object doesn't have enough geometry for the shadow to disperse and appear smooth.

Go to the lamp and under Shadow, increase the size value of the lamp. While you are there, try tweaking the other setting as well to get even better results (hover over the tooltips to see what they do). If not, try subdividing the model a bit, notice the shadow the heads casts on the flat chair shape behind is smooth.
Size: 128

Size: 1024


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Meaning of UV in "UV/Image Editor"
In Blender they speak about the UV/Image Editor. I cannot find the meaning of the letters "UV". What is UV standing for ?

Please see this thread: http://blenderartists.org/forum/archive/index.php/t-173777.html

Since 3D space and texture coordinates are stored together with the mesh to distinguish between them texture coordinates are associated with a separate letters sequence (U, V and W)
U and V denote the X and Y axes of the 2D texture that is projected onto the 3D model. 3D generated textures have another coordinate W that is equivalent to Z

is there any meaning associated with the letters U and V or is it just that they stand for X and Y axis ?

No, its just a sequence of letters to distinguish texture space from 3D space, since texture coordinates are stored together with the mesh.

But then you also have W,X,Y,Z for quaternion rotations, so it's somewhat misleading unless you know the context of the axis. As far as I understand it, UV was just the arbitrary designation of texture space when the concept was created.

It's just the three letters that come before X, Y and Z in the alphabet.

I think this is an amazingly uncovered area of Blender.  Lot's of tutorials show how to use textures; however they'll often cover specific answers for certain activities.  I know I would like to understand this a lot better! :-)    The Related Questions to the right have little detail related to UV.  I've seen complex tutorials using UV and nodes, and still fail to grasp some underlying structure about the data and nodes. Perhaps this or another question could be expanded to include the UV relationship via the mesh, nodes and images. Please include link.

@Cyberchipz you can ask a separate question, that will be easier for other users to find a specific answer.

@Denis, I've been meaning to ask, doesn't my rep get lower when I ask a question?

@Cyberchipz If you ask a good question people will vote for it, and each upvote will give you 5 rep.

The W in UVW also conflicts with the W in XYZW homogeneous coordinates, also known as "that thing you do where you have 4-vectors for points in 3d space so you can multiply them through 4x4 matrices, and related deep magic". Just a unfortunate side-effect of growing systems arbitrarily assigned. Did anyone even think that 3d textures would exist when UV was drummed up? (Hell, did it even come from texturing in the first place?)

U V and W  co-ordinates are the same as X Y and Z co-ordinates except U V and W are used to describe the co-ordinates of a MESH while X Y and Z describe the co-ordinates of Z-SPACE. but, the UV editor is only 2D so the W co-ordinate is not seen leaving just the U and V co-ordinates, hence the UV editor.
-Noah

I'd like to see more details in this answer; obviously there's a concept regarding the use of textures that, for myself, once understood could facilitate a concept in Blender's use that would improve my ability to use the texture system, as that and the nodes seem related, especially as it relates to the data output and others.

Let me begin with the wrong answer for what UV mapping is... Imagine we want to use a photograph of a real cereal box and line it up on our virtual cereal box so that it can be applied to the surface.  With a camera, we might capture three sides of the cereal box.  Now imagine a dot, positioned on the photograph where those three sides of the box come together.  Our goal is to get that dot from the photograph, to line up at the correct corner of our virtual cereal box.
The correct answer is to do the above backwards, except, one dot won't do it.  UV mapping is the process of placing all the "dots" from our virtual box onto a photograph.  Since a 3D model is made from a collection vertices, we let each vertex represent a dot, and then place those dots on the photograph where they belong.  We let the computer distort the photograph, as necessary, so that those dots match up with their associated vertices.
Each triangle in our 3D model is represented by three vertices.  Each triangle is filled in by distoring the pixels from the photograph, that are associated with that triangle, as defined by "dots" we laid on the photograph from our 3D model.


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Creating an object out of other objects
I was wondering if I could make an object out of other objects.
Example: The surface area of a cube will be made out of small hexagonal prisms.
I was wondering because I would like to create an armored suit made up of small triangular prisms. Also I want for the triangular prisms to be part of the mesh so that when I add an armature to it, it will move with the mesh.

1) Duplifaces (or dupliverts)
After creating the object to duplicate (hexagon in this case) and parented it to the armored suit, you should enable in the parent's Duplication panel (in the Object tab) the option Faces.

By enabling the Scale option, the hexagon will be scaled accordly to the face's size, so in the part of the mesh where the quads are more dense, you'll have more dense hexagons too.
Till you don't Make duplicates real, the hexagons will be attacchet to the mesh. This can be really helpful in animating meshes with shape keys, or transfer cloth simulation from the parent to the child without involving all the duplicated geometry.

Note: that you can study the hexagon pattern in a way that can cover the whole suit without leaving spaces, in order to completely replace the base mesh, but a more suitable way to do this is:...
2) Tissue add-on
As stated by the creator:

Tessellate tool allows the user to copy a selected object (Component) on the faces of the active object (Generator), adapting its bounding box to the shape of quad-faces.

There are a few option that can help you in the modeling, such as automatically vertex merging, proportional Z-scale. I think that is currently the best option to repeat a pattern on a surface while adapting the geometry to the face scale and get an organic look.

I was in hurry and I didn't used hexagons but octagons because the pattern was easier, but I'm sure that with some time you can get the effect you want.
The add on is currently in develop, so it still doesn't support shape keys, uv,... but they are working on.
Here's the blender artist thread about it.

The add-on include also another feature, called "Dual mesh" that:

... modify the selected meshes creating dual meshes. Dual Mesh output is a polygonal mesh derived from the triangular mesh. Quadrangolar meshes are automatically converted to triangular before.

Balsically youll'get a pattern of hexagonal N-gons from every mesh, which you can extrude.
Triangulate your mesh, that simply run the command and you'll get:

Than you can extrude individual faces to get an invincible-dragon-scale armor:

Credits:
Armor suite model from blendswap made by simitron

This is certainly possible! We might be able to answer more specifically if you could explain what you're envisioning more clearly, maybe with a sketch?
The poke tool might get you started in the right direction.

Here's a great tutorial on it, that includes several examples of incorporating triangular prisms into mesh: https://www.youtube.com/watch?v=0rXDVF_PijA


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Saving images with transparent spacing between islands
I am trying to save images from Blenders uv editor with transparent background but opacity on the painted parts. How can I achieve this? The reason I want to do this is because I use a filter inside my painting app that blends all the colors of the edges on each shell to prevent bleeding. This is a huge time saver. See attached pictures.

I wish to be wrong, but I think there is no way to automatically clean pixels outside the islands once it is filled.
When you create a new image, you need to activate "Alpha" option so you start with a clean background that will allow you to save the image like you want.

Also, remember there is a Bleeding option in Texpaint > Options > Project Paint

To save images with transparency, your image should have alpha info stored into. Has it? Can you provide an example of what you are trying to save?

I always paint textures in .png. But in Photoshop i generally just have a color filled background when i paint because it's more easy visual wise. >Carlo have you looked at the picture attached?

Before you start to paint use this method in this answer http://blender.stackexchange.com/questions/28863/how-to-start-with-nothing-on-texture-then-paint-texture-on/


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Blender UV Help
Hi I've got a blend here:
It has UV's, but only visible when selecting each object in edit mode. Each UV seems to be going to a different UV Map.
Could someone guide me on where to go next in my blend to create the simple UV?
Setting the alpha on the UV or texture (set it to background) is one of the troubles.

Please include a screen snapshot so that others may get a better idea of your specific problem at a glance, in addition to your blend file.

Each object will have it's own UV Map. The UV Map is how the texture is mapped to the vertices. So, you need one UV Map per Object.
If you want to view UVMaps for all 4 cushions, you have some options:

You can join the cushions into one object (select all the objects in Object Mode and press Ctrl+J). Then, you can just resize the current  UVMaps to fit on the texture.
There is a 'Show Other Objects' option in UV Editor -> View.  This only works if you have multiple objects selected, and they are using the same texture. With multiple objects selected, you can still tab over to edit mode. but you are only modifying the active object. (the active object is the last object selected)

The UVMap outlines are light grey and hard to see. But, with 3 cushions selected, if you look closely, you can see all the overlapping islands in the texture window.
hopefully this helps some.


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Best background for cut outs
Often I create a 3D scene in order to save the 2D image and do some post-production in Photoshop. Also in some cases the final result (after post) is an Isolated on White image. What is the best way to do this ? Should I create a kind of Infinity wall (Cyclorama) in Blender and use that as a background ? And making it easier to judge the image and also maybe the easiest for post-processing ?>
Like this image below. I created a plane as background (and the World is black). But cutting out the dices would be a lot easier when I would not have this background. By the way ... I want to keep my shadows (because I need those for the final image).

Related - http://blender.stackexchange.com/questions/3002/using-scenes-and-render-layers-to-composite-an-object-isolated-on-white-backgrou

Likely in your situation, you would want to render the dice as a foreground layer, the floor with shadow as a separate layer, and then turn on transparency in the render settings. That way you will get transparency where the black is now.
In Photoshop, you can add a background colour layer with a gradient and blend it into the floor layer easily. No need to render something simple like that.
Render Layer Settings
Please note that the blocks are on Layer 1 of the viewport and the Floor is on Layer 2. In the render layer panel, we select Scene Layers 1 and 2, and then assign Layer 1 to Render Layer 1 (named Blocks) and Layer 2 to Render Layer 2 (named Floor). Make sure the Combined pass is enabled for both layers.

Enable Transparency

In the UV Editor, select Render Result, then you'll have the option to switch between the 2 rendered layers. You can save out each layer as a PNG file (RGBA).

Output Blocks PNG (has alpha channel, though not obvious on SE page here)

Output Floor PNG

Bonus Tip
If you were finding you were re-rendering the image a lot, you could enable compositing and add File Output nodes to write the PNG's to disk as part of the render process. I can detail that process if need be.


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Transparent render layers
I am trying to figure out how to work with render layers. Now I have two render layers connected to the output via Alpha Over node. But when I render the composite output layer is not the combined output of the two separate render layers. What is my stupidity?

related: http://blender.stackexchange.com/questions/7573/how-do-i-composite-render-layers-in-2-69-using-cycles, more explanation: http://blender.stackexchange.com/a/3003/3710

Cycles or internal? The question is tagged with cycles, but you are using internal (screenshot).

I edited my question. How to get the composite output I want (the combined render layers) ?

You want to have both cubes, right? Please try to explain what is wrong with 3pointedit's answer and what you don't understand exactly.

done. see my added comment

I think I understand this idea of transparency now. But this means that if i want a combined layer of two render layers (with a background) I have to define a third render layer that consists of both individual render layers ?

Let us continue this discussion in chat.

It could be that you are not actually providing the compositor with any transparency. The alpha output socket from the scene node will just be a solid white unless you check the following properties:
Blender Internal: Turn on Shading > alpha > transparent, in render properties.
Cycles: Turn on film > transparent, in render properties.

Thanks for explaining how to work with transparency / alpha channels. Maybe I was not very clear in my question. I have now added a new picture showing the composite layer in cycles blender. Why is only one render layer in the composite layer ? I want both render layers in the composite layer. How to do that ?

@JanScherders Simply because your images (see the render layer preview window) are not transparent. As I suggested, read this post carefully. Here is a blend, open it and hit F12: http://blend-exchange.giantcowfilms.com/b/488/


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How to rename active or first texture slot of a material from script
I have a tool that I've written that takes blend files and converts them into quake 3 maps. This automates a ton of stuff that saves me a lot of time, but there's still several tedious steps before getting to that. One of those steps is splitting complex meshes up and generating textures and materials for each object. To keep things simple for editing, I'd like to have object name, mesh name, material name and texture name be the same for each object.
To accomplish this, I've found and used the batch rename data blocks script located here. For how great this script is, there's one thing it lacks, that being the ability to rename the active or first texture for the materials. I've attempted to access material.texture_slots[n].name and change this value, but got an error that it was read-only.
What is the appropriate api/process to rename images attached to materials? For what it's worth, all images are packed, generated textures.

While the script you mention doesn't appear to be updated you should look in the new contrib addons git repo instead of the old svn one.

@sambler thanks for pointing that out. :)

I realize I just posted the question but I solved this myself not long after. You can also rename the texture names and texture image names with this script by modifying the block of code that renames materials like so:
        if self.rename_material:
            if ob.material_slots:
                for m_slot in ob.material_slots:
                    if m_slot.material:
                        if m_slot.material.users == 1:
                            if (self.rename_use_prefix
                            and self.prefix_material):
                                m_slot.material.name = self.rename_prefix + name
                            else:
                                m_slot.material.name = name
                        if m_slot.material.texture_slots:
                            ~~~~VVV Added The Following VVV~~~
                            if(len(m_slot.material.texture_slots) > 0):
                                m_tex = m_slot.material.texture_slots[0]
                                m_tex.texture.name = name
                                m_tex.texture.image.name = name

Obviously there's some checks that could be done such as number of users and such. I'll post back as I polish the script.

"I'll post back as I polish the script." -- And yet, this never happens, as expected. :-)


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Volumetric Spot Light with Cycles
I'm using blender 2.76 rc1 with an AMD Raedon HD 7900 series, I'd like to create a volumetric spot light with cycles render. I set the volume scatter (density 0.1) in volume and mist pass in world, and put the spot light slightly below the street light, but, there isn't a volumetric effect.
UPDATE 1: I tried to set volumetric light in a pc with an Nvidia graphic card and works, I think it's an incompatibility problem
UPDATE 2: I read the wiki blender of openCL status, and talks about the AMD limitations, including the volume:

AMD
Limitations
Initial split kernel patch was done by AMD and was aimed to make Cycles render on Windows platform. This kernel works reasonably well with simple scenes, but has much harder time to work on a production files, it also lacks following features:

Transparent shadows (they're disabled due to AMD compiler issues)
Correlated multi jitter pattern, SSS and Volumes, which could be
  added to the split kernel, but prefer to focus on making existing
  feature set rock-solid first.
Branched path tracing which is quite tricky to integrate into current
  implementation of split kernel and supporting it will mean we'll do
  split kernel once again

.

related: http://blender.stackexchange.com/questions/16594/how-can-a-light-cone-volumetric-be-setup-with-cycles http://blender.stackexchange.com/questions/15920/holographic-lighting-in-cycles/15921#15921

I tried but doesen't work, could you give me a .blend example?

For volumetric lights you need to control a few things:
The emission values of the lamps need to be a bit higher than normal to compensate for loss due to the volume Scatter.

Rendering will be slower, a lot noisier, and with lots of Fireflies, so be ready to bring up the samples and clamp indirect samples. The best solution time/quality I've found is using branched Path Tracing and increasing the volume samples and a value for clamp indirect around 3.00

Work with the lowest volume scatter value that still yields the desired result. Higher values will be even noisier and the lights will need to be even brighter.

Keep in mind that volumetric light effects are better seen when the background is dark. How you combine your mist pass will make a huge difference as mist will tend to make things brighter and make volumetric lights less visible.

In my opinion a more realistic approach would be not to use mist, but to use volume scatter and volume absortion together.

sample file to play with:

The sampling tab gives me only those options -> http://imgur.com/bH78sI8

I'm using blender 2.7 rc1

i noticed that the branched tracing path is enabled only when i disable the compute device. I use an amd raedon hd 7980

http://wiki.blender.org/index.php/Dev:Ref/Release_Notes/2.76/Cycles newer versions of blender have better support for AMD cards

i installed the daily build version, but isn't unlocked; it's possbile without the branched path tracing to see the volumetric light?


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Why is Blender Guru UV unwrapping?
I am doing this tutorial of Blender Guru. And about 15 minutes he is UV unwrapping the mesh. Why is he doing that ? Although I am a beginner I think I understand the general purpose of UV unwrapping. Buy not what Blender Guru is trying to establish here.

UV unwrapping allows you to gain more control over how a texture is applied to the surface of the mesh. Without a UV map you can only map a texture through various automatic methods that rarely fit well on a complex mesh.
If view the part before and after the UV map is applied in the tutorial (around 15:50), you'll see how using the UV map affected and improved the look of the object.

He needs uv coodinates for the grunge texture introduced at min 18 and also use that to have better control on the procedural texture.

The cube on the right is flattened/unfolded so a texture can be applied. On the left is what it looks like after it is unfolded. Where it is cut to unfold these are called seams. In the video he places the seams to unfold the object.

By creating a 2D view of the object you can add a texture in an external editor (for example) exactly where you want the texture to be. The 2D version is mapped to the 3D object ... UV Map

It's so he can place the texture on the model. Without unwrapping it first, you can't put a texture on. It's just how it works, you can't project a 2-d picture on a 3-d object unless it is also 2-d.


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Strange Shadow on mesh?
I am doing this Blender Guru turorial. When I look at the metallic text I see this "shadow" on the inner sides of the text (see image). Now I am not certain what is the reason for this "shadow" ? Is it a shadow or did I do something wrong with the UV unwrapping (something that is very new to me) ? My file is here, the textures are packed into the file.

Hard to tell without the textures: http://i.stack.imgur.com/h0W2Q.jpg most likely a seams or mapping issue. Pack the textures into your file next time.

Yes there is a mapping node with XYZ scale set to 2. The texture is probably non-seamsless.

besides that you have a lot of duplicated geometry

As @Carlo suggest, the straight line is not a shadows, but the texture instead.
By changing size in the Mapping Node, you are distorting the image and the UV Map doesn't match as expected.

If you toggle muteM Mapping Node, your texture is correct.

In the Blender Guru Example, the Mapping Node is applied to the Noise Texture to achieve a "scratchy" effect.

what do you mean with muting the Mapping Node ? Sorry, I am really new with UV unwrapping and mapping nodes ...

I changed the scale and now it is solved. I guess that was what you meant with "muting". Thanks !!

@JanScherders nodes can be bypassed (or muted) if you select them and press M, very useful to leave your node tree intact and troubleshoot problems.

@parameciostudio I changed the scale from 2.0 to 1.0 and the problem seems to be solved. Is this the correct way to solve this problem ? You showed a Blender display where you can see that the UV map does not match. How can I create that display myself ?

The node is colored in red because it is muted. That means it is ignored. You can toggle muting by pressing M. If you don't need the node "Mapping" anymore, you can delete it by pressing Ctrl + x


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Size of Image Textures
How do your decide what size of image texture you need ? For instance on CGtextures.com you can download image textures in sizes S, M, L and Huge. In this tutorial of Blender Guru he uses image textures of size H(uge) for the front of the text but size S(mall) for the sides of the text. I don't understand that.
Most of the time I want to create a TIFF file of about 5400 x 3600 pixels.

The size of the image texture you need depends on a number of things, including:

How close to the camera is the object? The closer it is, the higher the required resolution.
The size of the output render. If you render in high res, you should probably use higher res textures at least for objects close to the camera. If you render in low res, high resolution textures will mostly go to waste as the details won't show on the rendered image.
Type of texture: For instance, if this is an environment map, and you want sharp, clear reflections on glossy materials, you should use a high res environment map for image based lighting. If you don't care about the reflections and just need to get nice lighting and environment colors, you can use a low res, blurry image.
If this texture is used for displacement, normal or color, again it depends on how much detail you need, and this determines the resolution you'll choose for the image.
As you can see I'm not specifying any actual pixel sizes, since as the saying goes, "everything's relative". Your starting point is your render output resolution, and the rest is experience and trial and error.


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Bevel Tool and Mac mouse
when using the Bevel tool you can change the number of segments by scrolling the middle mouse wheel. At least when you are working under Windows. But how to simulate that with the Mac mouse (I know how to Rotate, Pan, Zoom with the Mac Mouse).

After you've left-clicked to accept the radius, the bevel-tool is still active and you can

press numpad + / - to change the segment count. If you don't have a proper numpad: in Preferences, go to Input and check Emulate Numpad
or.. press F6 and adjust segments from there:


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Blender Video Editor: How to move a picture or movie from place a to place b and capture the movement into the video?
Let's say I want to move a picture in the Video Editor from place a to b, over 100 frames. A way to do this is to create 100 pictures and adjust the coordinates of each one in each frame. It's gonna take forever! and 100 frames are very few! Can I automate it?

Yes, keyframes will allow you can automate your goal.
Select regular strip.
Add a Menu/Effect Strip/Transform strip to a regular video/image strip.
Select new transform strip.
Keyframe the position.  Frame 1.

In the image above the mouse was used the to get the [Insert Keyframe] menu option.
Next a second keyframe on frame 100.  Yellow indicates key frame.

Next Blender places the images on frames 2-99 via interpolation.

There are tutorial resources here a blender.stackexchange and other video websites.

http://blender.stackexchange.com/questions/15355/resources-for-blender

https://www.youtube.com/watch?v=EcInAv9iHmU&index=15&list=PLda3VoSoc_TR7X7wfblBGiRz-bvhKpGkS


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Blender Fuzzy Camera Rendering Problem
I am rendering a documentary project and the sampling size is really high for each image. All the images rendered don't look fuzzy but when I combine them together for a film for some reason they look fuzzy when the camera moves. What do I do to make it so it doesn't look fuzzy when the camera move?

Can you upload an example video? It is hard to be sure of what you mean otherwise.

I just joined this site and this might sound nooby but how do I upload a video to show you?

Well, you could record a GIF with a program like LICEcap and attach it like an image, or you could use youTube and post a link in the question

Okay, I will send a link to a zip file download in a sec and it will have a quick scene example. In this scene you will notice the golden picture frame being fuzzy and part of the wall behind it.

Nevermind the zip file, the zip file was too large so I will just upload it to YouTube and send you the link when it finishes.

It is still processing but when it finishes uploading the YouTube video should be here: https://www.youtube.com/watch?v=gFK8hmKUXw8&feature=youtu.be

Alright, I'll check it later

Okay it is finished, make sure to watch on 1080 to be able to see the fuzzy. For some reason it is more difficult to see the fuzzy on YouTube but if you look closely u can see it in picture frame area and the wooden wall behind it.

You need to animate the Seed under Render Settings:

You can do this by hovering over it and pressing I, and then moving some frames, changing the value, and again pressing I.

What is the seed? What does it exactly do? Thanks for the help so far btw.

@AustinH. I included a pic. Basically what it does is change the pattern for light rays I think. If you want in-depth info on what the seed does mechanically, then try Google.

@NoviceInDisguise the seed can be animated withot the need of keyframes by clicking on the timer icon  to the right of the value slider


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Cylinder Subdivision Surface Modifier Problem - Smooth Shading
When I add a cylinder in blender and then add a subdivision surface the vertices of the cylinder get all rigid and pointy. How do I make the cylinder have smooth faces when using the subdivision surface modifier without it making the vertices rigid. I want the cylinder to be smooth so I can model something like a cup. Even after I add the subdivision surface and then put smooth shading the vertices are still rigid and pointy and even when I subdivide it as well.

Please place a screen image in your question so the question is easier to understand.

Thank you for your help I understand the issue now! before applying the subdivision surface I needed to put an edge split on a triangle fan type of cylinder.

Related - http://blender.stackexchange.com/questions/6425/keep-sharp-edges-when-using-subdivision-surface

To subdivide a cylinder with a Subsurf modifier, you'll need to add holding edges to where you want the edges to be sharp.  This can be achieved by using the bevel tool.
While in edit mode, Alt-select the edges that you would like to be sharp, then press Ctrl-B to set a bevel width.  I set the amount of Segments to '2' and a Profile of '1' so that if I need to remove my holding edges, my original edge will be where I originally had it before beveling.

Afterwards, you can add additional ring-cuts on the flat surfaces (Ctrl-R) to avoid any visible triangulation in the rendered result:

Use shading smooth and an edge split modifier and use high vertex density.
No Subdivision Surface was used below.  At this simple stage you may decide it unnecesary.  Feel free to delete your current cylinder and have a fresh start.
Below are cylinders with different vertex density values selected at creation time.

Below closeup of active edge split.

Below closeup of disabled edge split.

You can increase vertex density as indicated below.


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How do I focus the camera on a certain area or object?
I was working on a scene and the camera moved pretty fast in it that you couldn't even see the object in it. So I would like to know how you focus the blender camera on an object so that when the camera moves fast you can see that object clearly.

Are you using Cycles or Blender render? In which way you are controlling the focus? Are you using Depth of Field, Motion blur, Zoom blur or any compositing node setup that involves camera's focus? Related: http://blender.stackexchange.com/questions/18386/can-i-control-depth-of-focus-v-depth-deph-of-field

I think you mean that the camera has to look at the object continuously, depending on its movement?

Tracking
I think the term you wanted to use is "tracking". Focus refers to whether the camera is in-focus or blurred.

Select your Camera
From the Constraints context add a Damped Track Constraint
Set the Target to be your object you want the Camera to follow
Set the axis to -Z (that's the direction the Camera looks out of)

Focus
If you want to set the camera's focus, (as in blur), add an Empty to your scene, then from your Camera settings specify that the Empty is to be used to specify the point of focus. Position the Empty accordingly. Adjust the F-Stop to control the amount of blur.

How do you in-focus the camera on the object so background is blurred?

@AustinH. Please see the update to my answer.


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Blender Cycles Rendering Speed
I want to render scenes and things faster on my computer but I want it to be good quality as well. I set the sampling to around 200 samples and it takes so long to render just one scene on my computer (around a whole day for a couple seconds scene). Are there any upgrades I should add to my computer and if so please let me know. I have a AMD FX-6300 Six Core Processor, 8.0GB RAM, NVIDIA GeForce GTX 750 Ti and 1 terabyte hardrive. I enabled GPU rendering properly as well but it takes forever to render a whole scene. My computer is around 9 months old.

I'm voting to close this question as off-topic because it is not about blender, it is asking for a hardware recommendation.

It is about blender cycles rendering speed. Blender settings involve a graphics processor even for NVIDIA. I was just wondering if my hardware may be the case and if it would suffice and if I need to change any rendering settings.

Blender.org recommends a few setups including recommended and production grade. blender.org/.../requirements - but we avoid recommending specific brands. There are two parts to getting decent render speeds: 1) hardware 2) scene optimizations (depends on the scene..can include material tweaking, baking, compositor, render layers. ). Also consider renderfarms

I have heard of renderfarm before but for some reason whenever I go to their site it never displays the webpage and says it is not available.

@AustinH. There are many different renderfarms.. The post zeffi linked lists several blender-oriented services. (e.g. sheepit, a free distributed service)

Do you have to enable an addon in blender for sheepit? Like with renderfarm.fi?

@AustinH. Nope. Their website should explain how to use it: https://www.sheepit-renderfarm.com/faq.php#howdoesitwork


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Film Grain After Render
How do you get rid of film grain in a render? I made the sampling high enough and I just want to get rid of the film grain and make the pixels look smooth.

Are you using Cycles oder the Blender internal renderer with some global illumination? How many samples are you rendering per pixel? If there is still grain, it is obviously not enough. Especially for refractive materials and effects like caustics you will need multiple thousand samples. If you are rendering indoor scenes, portals might help to guide the renderer towards the light.

I am using blender cycles and 200 samples. I am rendering an indoor scene but there are no windows to place the portal at.

200 samples is definitely not enough. You should probably render 2000 or more, depending on your light setup. What you can also try is to disable Reflective Caustics and Refractive Caustics under the Light Paths settings, if you do not need the effects.

But it would take like 20 days to render 1 scene so what should I do to render faster?

Since there is no film involved in any of the process, there is no "film grain". Just noise. Bring up.the number of samplea to a point where the noise is tollerable and the render time is still manageable...


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Clamp Settings for Getting Rid of Fireflies
To get rid of fireflies in blender cycles, under the sampling do I change the indirect clamp to .98 or the direct clamp to .98 or both?

Clamp indirect. 0.98 might be too much clamping on the highlights. Tray a value like 3.0

First clamp cut the light value to the maximum you put so try first using hight values and then lowering from that as if you put it too low it will remove some light that is "real".
Second, you want to cut first the indirect light as it's normally what make more fireflies and direct light value is higher.
I recommend to start using a value of 100 or 10 in "clamp indirect", and reducing from it.

I always use a value of 9.0. Be careful with that. If you increase that value a lot your scene will lose brightness. If it continues rendering many fireflies I would try other tips:

Increasing the number of samples
Reducing the specular color below or equal to RGB(0.8, 0.8, 0.8)
Using bilateral blur node on compositing

I think when you said "If you increase that value a lot..." you really mean decrease as with higher clamp value you allow more light.

That is said on the blender wiki page. If you increase clamp values you can lose brightness in your colors (http://www.blender.org/manual/render/cycles/settings/integrator.html#scene-settings). So you can remove pixels which contribute to that bright colors.

From the wiki " However note that as you clamp out such values, bright colors in other places where there is no noise will be lost as well." It said when you clamp it, that is when you lower the number


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Rendering Backwards
Is there a way in blender cycles render engine to render a scene backwards instead of forward?

You mean in terms of frame order?

Yeah, but some keyframes can't be put in a backwards sequence for example if you are rendering an explosion backwards, so how would you render something backwards instead of foward?

Is this a workflow question? As in, you decided the end of your animation is a higher priority for rendering than the beginning? Or do you just want it to play in reverse? Because depending on which it is, the solution will be very different.

I just want to render the animation in cycles as an avi_raw video in reverse using blender

@AustinH. It's recommended to render everything to an image sequence before rendering to a video format. After the animation is rendered it's not hard to reverse the frames by enabling Backwards in the VSE

Once you've rendered the animation to an image sequence, import that into the VSE (in a separate .blend if you prefer). To add the image sequence, press ⇧ ShiftA> Image and select the images in the sequence.

Ensure the scene render dimensions, end frame, frame rate, etc. match your image sequence.

Set the output settings to render to the video format of your choice.

Enable Backwards if you want to render the frames in reverse order:

Render (F12)

Good answer but not to this problem. OP asked about 'Rendering backwards' not making the already rendered animation play backwards. People want to know how to render backwards because sometimes they need more of the last frames than the first. People finding the question may be frustrated with how the answer is workaround instead of specifically what was asked for.
IMO this was the right answer here:
https://blender.stackexchange.com/questions/157143/render-frames-in-reverse?rq=1

In the Sequencer, next to the timeline, on the right lower side of the window, select tab Strip.
It's now called Reverse Frames:


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Packing Texture Files In a Single Blend File
How do I pack texture files in a single blend file in blender cycles. I am using Sheep it Render Farm to render one of my animations and I need to make sure the texture files in this single blend file are packed so it renders with them.

Blender-> File -> External Data -> Automatically pack into .blend (click to activate) and save the file as usual. The images will be packed as part of the blend file.

Does it work if you have linked objects from other files?

I'm trying to pack my blend file to take it to Sheep It, but the problem is that when I hit pack all into .blend, it says unable to pack file, source path not found. But the textures are showing up and rendering fine?

This did not work for me since I tried to pack a movie. As of Blender 2.92, this is not supported yet. Manually packing the project will return "No new files have been packed" and packing the image manually will return "Packing movies, image sequences or tiled images not supported".

For render textures in Sheepit I do the following: File, external data, unpack all into Files, create directory if needed, and then.. .copy the textures manually to the Textures folder blender creates... next, zip all into a file and upload the zip to SheepIt. And it does it !
Hope it helps


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How to notice duplicate geometry?
In responding to a recent question someone told me that my mesh had a lot of "duplicate geometry". At the time I did not really understand the remark but I think I now begin to understand. I also became aware that for instance the extrude tool creates duplicate geometry.
Question When looking at my mesh how can I see that there is a lot of duplicate geometry and how to clean that up ?

Press A, W > Remove Doubles.

Usually doubles and duplicate geometry are unintentional, but sometimes you might have geometry that is intentionally in close proximity to other geometry so that you can't just do a remove doubles on the entire object.
There's a couple of Low-Tech ways that i'd like to suggest first.

If you press Z, in edit mode, you'll see a transparent / half opaque mesh. Faces that are duplicated in place will often appear darker.
.
Keep in mind that Backfacing Faces will also appear darker, so don't get confused :)
In Object mode, you'll see duplicate edges because they are drawn using the same color as the border of a mesh. Whether or not this is intentional I don't know, but it works well to track down duplicates edges.

In Face selection mode of Edit Mode, look for Dots on edges. Dots indicate the median of a face and should never been visible on edges.

You see this with geometry that you've accidentally extruded without translating the new face.
In vertex selection mode of Edit Mode, look for vertices which don't highlight surrounding edges:

removing duplicate geometry
Select everything in edit mode by pressing A.
Press ctrlV, click remove doubles, and you're done.
It's as easy as that.

After clicking Remove Doubles, you can set the merge distance by bringing up the Tool Shelf (T) and going to the bottom.


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Exporting Video From Blender Video Editor
I pasted the saved image frames from my blender cycles rendering into the blender video editor. How do I export the frames from the blender video editor into a video using cycles?

After you placed your images and set their duration in the Video Sequence Editor (VSE), all you need to do is set up the video format (lower red rectangle in the image below) you need and render as an animation (upper red rectangle).
When there's content in the VSE, it overrides anything else you have in your scene and when you render, it will render out the content in the VSE, instead of using the rendering engine to render your scene.

Will VSE override if sequencer isn't checked in the post processing panel of render properties?

As far as I know it will, it always takes precedent in my scenes and I've never changed this parameter.


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Texturing a Balloon
I am doing some tutorials with balloons and found this post about a balloon shader. I want to apply the shader to my balloon (in the image only one balloon visible). In this shader image textures are used. And the writer says "For unwrapping I selected the sphere-like part and used the unwrapping function “UV-Sphere” with “View on Equator”. It worked best in terms of texture stretching."
I am a real newbie in UV mapping and I don't understand this.

After the UV unwrapping (UV Sphere) I have this result. Should I do something more or is this OK ?

View on Equator is option of the Sphere projection unwrapping method, and it's used by default (you can see it in the Last operator panel, or F6 after unwrapping) . I.e. Blender will automatically consider this direction of the unwrapping sphere.

Sphere projection will cause serious texture stretching. If you plan to apply a seamless texture to a sphere, you have to choose between stretching and seams.
This is what stretching will look like:

This is what seams will look like:

To avoid both seams and stretches you must use texture painting or a shader without image textures.
I suggest you start with doing a real UV-unwrap and see how it turns out.
It is like imagine your model is built with paper, then cutting it open to be able to flatten it out without making any wrinkles.
Select edges like this and hit Ctrl+E to bring up the menu. Select "mark seam".

When all the cuts are made, hit u to unwrap. Select "Unwrap" at the top. Open a new editor (I always use the timeline) and make it display "UV/Image editor". See your unwrapping. If you don't see it, select all geometry in the 3D editor.

About texture painting, it is a whole new chapter. Google up some tutorial, do your homework and come back if you get stuck.


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Rendering Sound In Video Sequencer
How do you render sound with your video in the video sequencer? I already placed a sound strip with the video strip but how do you render the sound with the video?

Related: http://blender.stackexchange.com/a/47323/2843

Good question Austin,
---the below answer is if you want to render a file which has audio embeded, not for if you are having trouble playing back an audio file in the Video Sequence Editor---
Once you have audio in the video sequence editor, you're halfway there.
So you need to change your render output settings in the render tab

Change it to a video format (I normally pick h264)

Then change the wrapper format to Quicktime MOV, and the codec to h264  or PNG if you need lossless quality.
Below that, change the audio codec from none to AAC or MP3 (they're the ones I have had most luck with)

And then hit render and it should be in the final render output file (a .mov)

Make sure that

the audio strip has actually sound and you can hear it from your pc (sorry if it seems obvious)
the audio strip is placed in frames that you are playing (and there is sound for those frames in the audio strip)
the audio strip is not muted (H key - ALT-H to unmute)
the audio is not disabled from playback (look in the timeline menu "playback" there is a switch
there is not an audio level curve that sets the volume to zero (in the default video editing screen, see the upper left graph editor, after selecting that audio strip), in other words that the audio strip volume has not been animated (to zero)

What another answer says is not mandatory, afaik, unless you want to output a video (with sound): I have PNG output now and I can hear the sound while playing the video in the video editor...

What do you mean? A PNG output can not have synchronised audio, as it is just a sequence of images

Yes, it's true, and I know. Of course, if you need an output file with video and audio, you need to render your output to a video file.
But as the question asked, you should hear audio playing "in the video sequencer" anyway, it doesn't matter which output file type you set in the rendering panel.
Just as an example, you could need to output a mute video file, created mixing two other video file (both with audio) in the sequencer, and need to use their sound as mixing reference. Maybe then you render just video to the mute file and then add another soundtrack to the mixed video.

Aaaah see I was interpreting  austin as asking how to render with sound, I think you are interpreting austin as asking how to play back video with sound in the video sequence editor.


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Is there a way to visualize the tris of a scene?
Is there a way to visualize the tris of a scene ?

I want to visualize them in the viewport, because sometimes I want to turn the hidden edge of some quads.

The 'tris' count shown in the info header is only an approximated count of how many triangles the mesh will be converted to. The only way to see the triangular polys used is to triangulate the mesh. A non-destructive way is to use a triangulate modifier and enable wire display for the object.

I'm not certain that the modifier will match other triangulate steps but you can apply the modifier to ensure your final triangulated mesh matches.

Selecting All Triangles
You can use the MeshLint add-on to select all the triangular faces in your mesh.
Another way is to select a triangular face, Select Similar ShiftG > Polygon Sides and this will select all tris.

Rotating Edges
If you have a mesh where the quads have been converted to tris you can "turn" or "rotate" the orientation of the edge within that triangulated quad.
For example, in the screen shot below there is a Suzanne mesh that has been converted to all tris using the Triangulate Modifier. In Edit Mode if we select an edge that bisects a quad we can then press CtrlE and from the contextual menu choose Rotate Edge CW or Rotate Edge CCW depending on whether you want Clockwise or Counter-Clockwise rotation (for a triangulated quad it makes no difference which you choose, the result is the same).

Further details
This operation can also be accessed from the menu under Mesh > Edges. It can be performed in all three selection modes (Vertex / Edge / Face).
If you plan to do this operation many times repeatedly it would probably be best to assign a keyboard shortcut to it. While the contextual menu is open you can right click on the menu items and assign shortcuts.
An example utilizing the Mac's "Command" modifier key:

All quads are really made up of two tris with a "hidden edge" connecting two adjacent verts.  "Turning" a hidden edge means flipping which two verts are connected by the hidden edge.

I mean exactly what PGmath is saying

@PGMath thanks for clarifying. I get exactly what is meant now, didn't realize there was a name for that (a hidden edge). As for "turning", isn't the whole point of a quad that which two verts are connected is calculated automatically as the mesh deforms? I mean, isn't is supposed to "turn" itself? Otherwise a quad would be no different from two tris connected by a common edge, right? Unless OP is talking about a mesh that has been converted to all tris, in which case I will now add something more to my answer (how to rotate or "turn" an edge).

@Mentalist  I don't believe hidden edges are calculated on the fly.  The (biggest) advantage of quads is edge flows.

@PGMath Hey... it seems you are right, they're not calculated on the fly. This is actually kind of shocking to me, as I had been under the impression that they were calculated automatically to achieve the most desirable deformations. Maybe hidden edge orientation doesn't make as big of a difference as I thought. If it looks alright in the end all is well. But that still doesn't fully answer OP's question about how to turn hidden edges. As far as I know there is only a way to turn "real" edges.


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Text on a balloon
I want to create an image like below, so a balloon with text on it.

I have been googling for ideas (text, sphere, ....) and came on this earlier question. So I tried Shrinkwrap and Cast modifier.
Here is the situation before applying the modifiers.

This was after trying Shrinkwrap

And this after Cast modifier.

For me it does not look like it is going to work with one of these modifiers.
Question How to create the image of a balloon with text on it ? With one of these modifiers or should I try a complete other approach ?? How to do this ?

The problem is with the geometry of the text.  Text objects have horrible topology by default.  Try a remesh modifier on the text before the shrinkwrap/cast.

Is there a reason you want to use a text object instead of simply using an image texture?

I considered an image texture but since I am really a beginner with image textures, unwrapping and uv mapping that was not the route I was thinking of. But I certainly want to learn. Maybe it is less complicated than I think it is

In that case I will add an answer for both and you can see which you prefer.

one of my "challenges" is that a balloon is more complicated than a UV sphere

What is the geometry of the balloon like?

My answer used a UV sphere but it should work fine with your mesh as well.

after playing with both methods I think the Image Texture approach is the preferred route

Your problem with the Shrinkwrap modifier is that it requires decently even topology, and text objects have horrendously miserable topology.
Here is a text object with wire shown.  All those long skinny tris make for terrible deformation.

To fix this first convert your object to a mesh (Alt+C) and add solidify it slightly (because Remesh needs a 3D solid object, you can delete the solidification later).  Then add a Remesh modifier and knock up the Octree Depth until the detail looks good (I used a value of 6).  Also be sure to uncheck Remove Disconnected Pieces.

Click to enlarge.
Then you can apply the Remesh modifier and go into edit mode and delete the second layer of vertices to make it 2D again.  You can then apply the Cast and Shrinkwrap modifiers.  It should deform much better this time.

Here are a few pointers and tips:

Put the Cast modifier above the Shrinkwrap modifier in the stack.
Be sure to set the Control Object of the Cast modifier to the sphere/balloon.  And make sure that the origin of the balloon is at the center of spherical part.
The closer the text object is to the surface of the balloon the better.

I think you did not extrude the text before converting to a mesh, right ?

@JanScherders  Yes, I converted it to a mesh, solidified, then added the Remesh modifier.  I solidified it in edit mode with [Ctrl]+[F] > Solidify.  I am working on the texture solution right now too.

would it be different if you first extrude, then converted to a mesh and then would do no solidify ?

@JanScherders  No, I didn't think of that.  That should work fine.

I now also tried this method. I first added Solidify and then Remesh. When I apply the Remesh modifier the text object disappears and Blender says "applied modifier was not first and result may not be as aspected". When I undo this and try to move up the Remesh modifier my text object disappears again ?

@JanScherders  I actually didn't use a soldify modifier (though you could, just apply it before the remesh).  I wen't into edit mode, and hit [Ctrl]+[F] > Solidify.

If you are just trying to put text on a balloon, I would use a texture, not a text mesh.
To unwrap the balloon, I "cheated" and just marked seams around where the text was to be placed, the rest doesn't matter since you aren't putting any text on it.  Then after unwrapping I just scaled the rest of the pelt down and put it in the corner and made the important part fill the UV tile.

Then I exproted the UV layout (UV/Image Editor > UVs > Export UV Layout) and used it as a foreground image in GIMP to create this image to use as a mask on the balloon.

Then you can plug this image into the fac of a Mix RGB node with the two colors of the balloon.  White areas of the mask will get the second color and black areas will get the first color.  Then plug that into the color of your shader[s].

Here's a render:

I managed to find out how to add the Image Texture to my existing Node tree. Thanks a lot for your help !!! You really made me understand how to solve this kind of issues :)


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Armature is not modifying the mesh
I am trying to create a robotic hand, for the fingers I add an armature then parent the finger to the bones. Then when I go to pose mode instead of modifying the mesh it pivots the finger on that joint. I have done about 7 tutorials on armature and have all gotten me nowhere unlike other characteristics of  blender like editing, painting, using nodes, etc... seem to be more developed and easier to use unlike the armature option. I have been using blender for 2 years now and have never seen a feature more vague and underdeveloped than armature. Maybe it's just that I'm bad at it, but watching 4 hours worth of tutorials on it and getting nowhere really frustrates me.

In the first screenshot, it appears that your mesh has no vertex groups. As far as I am aware, skinning requires that the mesh has vertex groups with the same names as the bones in the armature, and cannot work otherwise. The vertices you want to be moved by a certain bone must be assigned to the matching vertex group. To add vertex groups to your mesh, click on the + button on the vertex groups panel (visible on the right side of your first screenshot). You can also automatically create the vertex groups by selecting the mesh, then shift selecting the armature, then hitting Ctrl + P and selecting Armature Deform with either Empty Groups, Envelope Weights, or Automatic Weights.

Thank you so much but just one quick question how can I make a sharp bend because right now when I pose the mesh seems to have a smooth deform, I just wondering how I can make a sharper bend in the mesh. Still thank you so much for that info.

Select your mesh, then open the menu in the lower left corner that should currently say 'Object Mode' and change it to 'Weight Paint'. You can play around with it until you get what you're looking for, but I would advise looking up a guide on weight painting.


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Cutscenes Blender Game Engine (BGE)
How do you add a video or film in the blender game engine before a level starts or something?

What you'd basically do is create a scene with a plane and a camera pointed at the plane, and make the plane use your cutscene or video file as its texture. Then, using a Delay logic brick or something similar, you'd switch from that scene to another scene, which contains the game stage or level.
If you want a live animation to play, just animate the camera and the objects in the first scene, and use a Delay sensor again.
This video does a good job of explaining a method of implementing the same method: https://www.youtube.com/watch?v=P2W_fQayYcA It's a video by SuperGloop.

I'm not an expert, but one way you might do this is to create a game scene and an intro scene.
Then animate your camera with LocRotScale or use a bezier curve

You can create your cinematic in a completely different scene, then use 'Load Scene' logic brick to switch back and forth between the actual game and the cut scene.


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Rendering a pixelated image
How do you make the camera in blender cycles render everything so it looks like pixels? I want everything in my scene to look pixelly like this image I found:

related: http://blender.stackexchange.com/questions/2586/how-can-i-keep-low-resolution-textures-pixelated

I just noticed you also asked this question. If you are looking to get a certain effect that the linked question doesn't answer, is it possible you could edit your question to describe how the effect you want is different?

I just edited the question to show what I meant :) This effect is different from the TV like hologram effect because I want it to look like pixels as shown in the image I put for this particular question.

@gandalf3 I don't see how the linked question is a duplicate...

@cegaton From the original version of the post I got the (wrong) impression that the OP wanted to simulate a low resolution display

Found a solution in compositing based on this BlenderArtists thread.
To pixelate a render layer or image, you simply need to use the distort scale node to scale it down, use the pixelate filter node, then scale it back up.
The amount of scaling up and down control the amount of pixelation.

EDITED: If you really want to reproduce the effect from the original image, with the pixelated outline as well, you need a slightly more complicated node setup:

Download blend file here.
Original vs. pixelated+outline side by side:

Is there a way to do this without having to add images to the image node in the render layers?

You can use your ordinary render layers node instead of the image node, I used this just as an example

Perfect just what I was looking for!

It is usually better to render to an image first though. When you render straight to render layers, when you close Blender, when you reopen it, you'll have to rerender to be able to work on it. When you use a saved image instead, it stays there, and you can continue what you started without rerendering. It's almost always best to separate your 3D work from your 2D instead of trying to do them at once.


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Adding Imprints On Objects
How do you add an imprint to an object in blender cycles? Such as a footprint on a piece of wood like on this image:

do a search for dynamic painting :)

@cegaton Probably not quite what he's looking for. I don't animation of it being imprinted is expected.

You might want to take a look at masks' using, connected with the Factor input as is done in this BlenderGuru tutorial (to be more precise, wooden floor material, but the lesson overall also is great)

@TARDISMaker my guessing powers are not so keen on weekends...

Couldn't you just unwrap to footprint using uv and add it to the object as bump map. This is for Blender Internal.

One way you can do that is adding another texture over the wooden one... You can add several textures, and mix them with several algorithms (see the color > mixrgb node) to achieve different effects...
this is a simple setup but there could be many others, more sophisticated:

basically, you add two textures to your material, and setup the "footprint" so that it doesn't repeat, and place it how you wish. In the picture the "mix" node is just mixing the two textures, but other modes are available in the node list
this method is took from here http://www.andreucabre.com/2014/11/controlling-texture-tiling-in-cycles.html

Are you planning on elaborating?

I just did. But there other answers to similar questions, too like
http://blender.stackexchange.com/questions/15207/setup-a-decal-material-in-cycles

There are various ways to accomplish this. I will share two methods that I've found work well.
1. The Transmission Mask Method (for stills)
This method involves modeling a simple foot object that will pass in front of surfaces that are to appear wet or imprinted upon. The wood material in this case uses the Light Paths node to mask between wet and dry shader mixes. The "Is Transmission Ray" output from the Light Paths node factors the mix in a way that any light hitting the wood material that also passed through either a Glass or Refraction shader will be shaded with the wet mix - else it will be shaded with the dry mix.
This is quick and easy to set up, however if you think you may have any objects made of Glass (for example) passing in front of your wood they too will trigger the wet material. As long as you plan your scene in advance, and know what else will be between the camera and your wood material, you can probably get by with this quick trick.
Use a Refraction shader on the footprint object with the IOR set to 1 so that no refraction actually occurs, but the rays passing through will now be considered "transmission" rays.
Here is a demonstration of the principle in its most basic form.
Basic transmission mask setup:

As you can see, while this has the advantage of being quick to set up, it has disadvantages as well. It doesn't render as transparent where the background is transparent. Also, when viewed from the side the sphere occludes more of the plane than you'd want. Instead of a circular area being yellow, you get a whole silhouette of a dome that is yellow. You might think that if you flatten the sphere enough you will get a circle, and this is true - however if you want to animate something like a footprint you will want the intersection to happen over the course of several frames, meaning the footprint-shaped object must have some depth to it. Adding depth means the silhouette will become at least somewhat visible when viewed from the side and look strange. This is why I present this solution as being alright for stills but not so good for animated scenes.
Example result:

(Thanks for the wood texture, Pixabay!)
Example node setup:

In the above example I subtracted the wood cracks from the mask because they don't need to appear wet, they just need to appear dark - and the glossiness of the wet mix was actually lightening them which didn't look natural, so I did a low-cut to exclude the really dark areas from the mask. This probably isn't necessary to do with most textures.

Note that passing through transparency is not "transmission", so you can even take it further and map fades between Transparent Shader areas and Refraction Shader areas if you a want a smooth falloff. Here is an example of a setup that creates a soft-edged footprint using the Z-height of the mesh:

2. The Wet Map Method (for stills and animation)
This method takes a bit longer to set up, but it's the right way to do it. And it works really well for animation.
Part I. Modeling and animating the brush and canvas objects
As with the transmission mask method, a footprint-shaped mesh object is required. I modeled mine starting with a trace of your reference image. Since the shape will move through the plane over the course of several frames, it needs to have some thickness for the imprint to be animated. I used the same mesh object for both. Here is what it looks like. Notice how it is intersecting with a plane.
The footprint-shaped mesh is your "brush object". The wooden surface is your "canvas object".
The foot and toes are rigged to a very simple armature so that they curve with the step. The water droplets are not rigged to the armature - instead they are animated with a Shape Key because I thought it would be simpler not to have a bone for each, but I wanted them to hit on separate frames.

I animated the step to come up through the plane instead of down into it, but it doesn't matter which direction you come from as long as the "brush" object intersects with the "canvas" object. The brush object must be a closed volume.
In most cases the brush object should move away from the canvas object after stamping into it. If it remains intersecting with the canvas object, it will continue to soak and spread out the wetness. Such soaking counteracts Dry and Shrink effects, if you use them (more on these later).
Unlike in the transmission mask example, we don't want the footprint objects to be visible to the camera. So uncheck these boxes in the Object Context under Ray Visibility:

Part II. Using Dynamic Paint to Create Wet Maps
Go to the Physics Context.
Select your canvas object and click “Add Canvas”.
Select your brush object and click “Add Brush”.
The default brush color is blue, which would be relevant for a paint map, but not for a wet map. A paint map transfers color information. A wet map transfers greyscale data mapping how wet a surface is, with black being dry and white being wet.
In the Dynamic Paint section, set the format to “Image Sequence”.

Specify the resolution of the output images.
The default 256 is good for initial testing, but you will want your final one to be higher.
Use your judgement depending on the size of your painted object in your scene.
This value is for both the X and Y dimensions, because your UV area is always a square.
Set the start and end frames for your animation. An image will be output for each frame.
Specify how many Sub-Steps you want to be calculated for smoothing the animation. If the brush collides with a face perpendicularly, Sub-Steps are not necessary because it will pierce through rather than trail across. See the step-count comparison below on a sphere that moved across a plane over the course of 6-frames:

Unwrap a UV map for your canvas object.
Specify the UV Map to be used (you probably only have one to choose from).
Specify the file path for your output images.

Press the button to “Bake Image Sequence”. The cursor will show the percentage done.
Once you've done a test bake to confirm that it's working, there are a couple more adjustments you can make to enhance the realism of your wet map.
Enabling the Dry option makes wetness gradually fade with time.

Enabling the Shrink effect makes wet imprints get smaller as they dry up.

Experiment with these settings if you want to simulate your footprints drying over time.
Part III. Using Your Wet Map in Cycles
After creating a new material in Cycles, open the Node Editor.
Add an Image Texture node and load the image of the first frame of your wet map sequence.
Change the source from “Single Image” to “Image Sequence”.
Set the number of Frames to be the number of images (frames) in your sequence.
Set your Start Frame to the frame in your scene when you want your wet map to kick in. In other words “wetmap0001.png” (or whatever yours is called) will begin at this frame.
Leave the Offset value at 0.
Enable the “Auto-Refresh” option.
Add a UV Map node and plug its UV output into the Vector input of the Image Texture node. Specify the UV map to be the same one you used for your canvas settings.
You might not need to do this if you only have one UV map on your object, since Blender will probably auto-detect it and know what to do - but it’s a good practice. It is necessary if you have multiple UV maps on your canvas object.
Example node setup:

Note that I didn't go so far as to factor in the wood cracks in this example since I wasn't rendering close-ups, but of course you can easily integrate that into your node setup if you want to. (See the example node setup for the Transmission Mask Method)
Example result:

In the examples above the drying effects have been unrealistically sped up for the sake of demonstration...and because it looks kinda creepy.


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Special Builds With Blender
I installed a special build from GraphicAll.org for blender. It gave me a .7z file after the download. How do I install this into blender or use it for blender?

You don't have to "install" that file into blender. That file IS a blender version! You just need to decompress that file with 7zip (http://www.7-zip.org/), a free open source compression/decompression utility which handles many formats. 7z is usually more efficient than .zip so is often used as alternative for big files.

What is the difference between that file and the blender on blender.org?

graphicall is usually hosting special builds that differ from the official ones: since blender is free open source, anyone can get it, modify, build, and share it on graphicall. this sometimes allow people to try experimental features -  which can be also broken, or broken on your platform. My advice: you can't trust totally who shares them. Be sure to get some more info about the author or that specific build before using it. Even without bad intentions, that build could by mistake damage your pc or do other bad things. Official versions are safe, and you can always trust them.


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Movie Clip On Plane
In blender cycles render engine, how do I put a movie clip on a plane so it displays the video? I want the video to be on the plane if there is a way.

This question was interesting to me for that I was working on that subject lately.  I solved how to play a video  withing an animation using the second solution proposed below.  However I would like to mention that in the latest release of Blender that is at this time 2.78.4 there is no option to import any formats like it is mentioned in the first answer below by @cegaton.  Maybe this is a temporary situation but because this, one has to use a texture on a plane and select movie as type of texture like it is described in the second answer.

At 2.8 for me its just workd if i imported from the file menu.

Use the Import: Images as Planes addon:

or press Shift+A and select Add -> Mesh -> Images as Planes.
In Blender 2.9x it's located in Add -> Images -> Images as Planes.

Select the video file you want to use as texture (and what kind of shader you want)

Blender will then create a plane with the dimensions of the video file and will create the materials for the texture.

Using the default values will make the video playback start on the 1st frame of the blender scene.
You can use the Frames control to limit the number of frames of the video you want to use. (for example if your video has 1000 frames but you only want to use 215 you'd set that value here)
The Start Frame control will allow you to delay the beginning of the video playback (moving it to 100 for instance will make the video pause for 100 frames and start playing on the scene's frame 101, for example)
The Offset control will allow you to choose the starting frame of the video (if your video has 1000 frames and you want to ignore the first 35 frames you would set the offset to 35)

Make sure auto-refresh is enabled.
NOTES:

The texture on the Plane will be visible only when the shading in the 3D viewport is set to Material preview or Rendered.

For older versions use Texture or Rendered.

The images in rendered mode do not refresh at every frame.

Read: Image sequence texture: no preview?

THANK YOU! Finally someone who understands it and was able to explain it!

You can do this with an Image Texture node (Shift+A > Texture > Image Texture). Once you have an image texture node, change the Source option from Single Image to Movie as shown. Make sure the plane is UV Unwrapped, and that you load your movie file path into the node.


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My Blender rendered pictures are pixelated
When I render my animation the output pictures are pixelated, can anyone help me fix this problem?

Related: http://blender.stackexchange.com/q/3473/599

As an extreme case, it could also be that your render view is so zoomed in that you can see the image pixels bigger than they really are. Try pressing Numpad "1" Key with the mouse cursor over the render preview: it will reset the zoom to 1:1 (actual resolution)


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Mix Shader Difference?
What is the difference between putting a diffuse shader 1st and then a glossy shader 2nd into a mixed shader or a glossy shader 1st and then diffuse shader 2nd in blender cycles?

Nothing, the difference is driven by the Factor input

It should depend on the "factor" of the mix, citing the manual:
"Fac
    The amount of mixing of the bottom socket is selected by the Factor input field (Fac:). A factor of zero does not use the bottom socket, whereas a value of 1.0 makes full use. In Mix mode, 0.5 is an even mix between the two, but in Add mode, 0.5 means that only half of the second socket’s influence will be applied."


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Animate UV maps in Image Editor
After unwrapping a texture in blender cycles in the image editor, is it possible to animate like scale, rotation and etc. of the unwrapped texture?
I want to be able to animate the unwrapped area.

there is a plugin that will allow you to animate the UVs: http://wiki.blender.org/index.php/Extensions:2.6/Py/Scripts/Animation/AnimAll watch: https://youtu.be/xlJ71XChDuY?t=867

Is it just a script i can run in the text editor?


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How do I import a .blend into another .blend?
In blender, Import has no .blend option..so how can I import .blend file in my current blend file?

There are two ways to import .blend files. You can use the Append (File > Append...) or the Link (File > Link...) operator.
Append makes a direct copy of the elements in the .blend file, while Link links the elements directly to the original .blend. The difference when it comes to working with these, is that when you use append, you can modify the objects in the new file. It won't cross over to the original file. With link, you can't modify the objects in the new file, but instead need to go to the original file.
Now both of these operators work a bit differently than you'll be expecting. Instead of directly copying everything from a file in like import does, they copy parts of the file, called datablocks.
A datablock is essentially a piece of information in a file.
When you click the link or append operator, the file browser will come up for you to navigate to the file you want to use. Once you're at that file, when you click on it, it will expand just like a folder. Inside there will be several folders for different parts of the file. What you'll probably want to do, is go into the objects folder, select everything (A) and then append/link them in.

I think the easiest way is just to open another Blender project with the object(s) you want to import, select them and copy & paste to your other project. That copies everything. I hope this helps. :)

it does not preserve color and textures.


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Blender Python: Where do I get an Image with all the indices for the edges and faces of a cube?
I just need to know the index numbers of certain edges and faces in a cube in blender.
Is there anywhere a diagram of that? Or can this be shown in blender as e.g. the length of an edge.

related: http://blender.stackexchange.com/questions/3249/show-mesh-vertices-id (possible duplicate)

Blender doesn't normally display the indices information but it does have a debugging feature that can display them. To enable debugging you type bpy.app.debug = True into blender's python console. Once enabled you will find an indices option in the mesh display panel of the properties region (press N to show the region) while in edit mode. Only the indices of selected items will be shown and your selection mode will define whether vertex, edge or face info will be displayed.


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Hide material in Blender
I'm working on a school assignment in Blender, I was following a Cycles tutorial to create a bear with fur (hair) on it. My problem is that since I applied that material, it takes minutes to change selection in object mode, even if I apply wireframe viewport, the fur lines remain there. Can I somehow hide it while I rig the character? Thank you in advance!

The hair particles are added to your mesh object through the modifier system. You can enable/disable the effects of any modifier for viewport and rendering, the camera is for rendering and the eye is for the viewport.

For particle systems you can also adjust the visibility within the particle settings.

Thank you very very much, I was looking at material at the whole time, not the particle system. I owe you a beer. :)


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Reflections on glossy balloon
I use the image below as my "learning vehicle". I have now learned how to model balloons, texturing the balloons and put text on the balloons. One of the qualities of this image is the reflections (of a window ?). I have no idea how to do that. Is this a background image ? Some HDRi lighting ?

I used the answer of m.ardito to create this test file. I create four planes with the array modifier and made these planes emissive. I also created a sun lamp. This resulted in the image below. Although I now have the "window like" reflections" I still have a couple of issues left:
1) I think I need a second lamp (sun lamp) for lighting the sphere but this gives reflections I don't want. How to solve that
2) How to get those window like reflections with sharp edges ? My reflections have very soft edges

The simplest (or maybe fastest) way would be add some squared light for the baloon surface to reflect.
In blender cycles, for baloons try a red glossy (adds some mirroring), and add a "light" shaped like a window (either four planes in a square pattern or a single "light" plane with an opaque cross frames in front), with its material set to "emission" (cycles).
In blender render, the baloon material should have a degree of "mirroring" and the light could be four planes with a white material having "emit" shading.
It's a matter of experimenting a bit.
If you need a whole complex natural environment reflected in the baloons, like trees, building, people, etc. only then you need really to use hdri.
basic blender render example:

I edit my answer to add some more, as asked by the OP.
If you would like to absolutely avoid other reflections, you could use environment lighting, instead of lamps like this (blend file will follow), or an area light instead of sun, or some more tweaks to avoid that big specular..
I'll check your blend file later (and add mine) to find why you have those very soft edges...
here is mine... http://amrc.altervista.org/wp-content/uploads/2015/10/baloons.blend_.zip

also keep in mind that stock image could also be post processed later to get a perfect result... this is quite common to achieve artistic results.
ABout your soft "window" reflection edges, they are due to your setting for the glossy bsdf node (you have a quite complex node setup in this file!)

set it to 0 for perfect sharp result, or adjust to your need
like

I tried to apply your suggestions but have some issues left (see my edit). Hope you don't mind to have a look ?

you're welcome. I added above a picture from another experiment I did today, later .blend file will follow.

thanks for you extended answers !! I now understand that the roughness of the glossy shader controls how blurry the reflections are. And yes, at roughness = 0.0 the reflections of the four planes are very sharp. But also the reflection of my sun lamp disappears ... don't understand that. In your file you have one object Plane but it consists of four planes ??? How do you do that ?

Glad to help. The 4-quad object is like 4 planes joined. I actually did it cutting from a bigger plane, but you could do it also joining separate simple meshes. Blender objects can be made of separate structures, even not connected by any edge. You could also do an object made by just points each not connected to anything...


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Building Animation
I was just wondering how I could do a building animation that the building process would scale each face instead of just making it visible. I couldn't find any examples though I have seen it in documentaries so I will try to explain it as well as I can. Blender has a build modifier that build your object using the faces, now the modifier just makes the faces appear. I want to know how if possible to make a growing effect on each face that will grow from it's center point to it's full size and will to this through out the entire object from end to end. If I can I might add some reference videos or photos if I find some.

I found a video but it is for cinema 4d link

Another one is link

The second video is similar to this For the first you may want to look at the animation nodes addon

Nearly the same result as in first video could be done using Explode modifier along with particle system with Emit from set to Grid and slightly changed options for rotation and emitting particles.

I believe going into how to do these things would be better served by tutorials elsewhere, so I have provided some links and suggestions of how to get started.
If you have specific questions, feel free to post those as separate questions on this site, unless they are specific to this answer.
If I were to go through all of the information here step-by-step, I believe it would be an unacceptably large amount of information. That being said, I may make a youtube tutorial on this one, as it was pretty fun to do. If/when I do, I will be sure to swing back around to this post and include a link or two.
For Drivers, I would recommend this Link, and youtube/vimeo.
For the Dynamic Paint Method - Learn up using youtube or vimeo I thought this one was pretty good
This just uses drivers, empties, and keyframing:

Warning not a very good implementation
I know people here can expand on at least the Canvas method used here to help you get the particle emission looking good.
As for the text disappearing, it is being boolean differenced by the moving mesh body, with a canvas plane parented to it - the text mesh is the brush.
The canvas plane also emits the geometry - in this case (again not the best with brush and canvas so any help modifying what should be done here is very welcomed).

The rendered effect:

Maybe a quick way to get a similar effect would be to put a simple Subsurf Modifier before the build modifier. This doesn't scale the faces, but with a high subdivision number (eg.6) it makes each face grow in smaller steps instead just appear one face at a time.

Use the build modifier.
Simple example:

Open a new blend file
Delete the cube
Add a sphere
In modifiers, add modifier, select build. If you are on frame 1 of the animation, you will see the sphere disappear.
Start the animation and the sphere will appear one face at a time.

See https://www.blender.org/manual/modifiers/generate/build.html

The OP knows it, it seems. And what about the "growing" he asks in "growing effect on each face that will grow from it's center point to it's full size"?


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make the scene look like an old television
How do you change what the camera sees in blender cycles. For example how do you make the camera make the scene look fuzzy like an old television. Here is an example image for fuzzy old television camera effect:

This question has been answered.

read this: http://blender.stackexchange.com/questions/15766/transparent-lines-for-a-hologram-like-effect and http://blender.stackexchange.com/questions/21391/how-to-make-a-texture-always-upright-relative-to-the-global-z and http://blender.stackexchange.com/questions/15784/repeat-a-generated-texture-in-cycles

Thanks but is there a way to do this with the blender camera itself, so when you look through the camera just the screen of the camera does that? Would I have to like make a holographic plane on the camera make it be parented by the camera so whenever i move the camera the holographic plane follows directly on the screen of the camera?


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Compositor: make the glare node effect only certain objects
I want some objects to be affected by the glare node in my scene but not all of the objects in the scene to be effected by it. But the problem with that is the glare node is used in the render layers panel so it effects the whole scene when I put the glare node in when I only want the glare node to effect certain objects. Is there a way around this? (This is in blender cycles).
Example Image Above

We need a screenshot of your compositor node setup

related: http://blender.stackexchange.com/questions/35853/one-part-of-the-render-layer-glowing/35860#35860

Done, I edited the post and placed an image.

So what parts of the image should glow?

That was just an example, I hid everything else in other layers, but I just want to know how to make any object you want to glow, and any object that you don't want to glow because by default when the set up is like that it makes everything glow, but I want to know how to make different objects glow.

The key is separating objects, either via object ID masks, render layers or any other method, then applying your desired effect only to the objects you want. http://blender.stackexchange.com/questions/3423/how-to-use-an-object-as-a-mask/3515#3515 or this whole tut: http://www.blenderguru.com/tutorials/introduction-to-the-compositor/

to use id masks, see http://www.blender.org/manual/composite_nodes/types/converter/id_mask.html

If you render those objects on a separate layer you can apply the glare just apply glare to that render layer.
E.g.


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Objects in the middle of plane on hair particle system
I'm tring to distribute an objects group in a plane with hair particle system, but the objects are positionated in the middle of plane and not in its surface... any advice?

The origin of the cubes in your group is in the center each cube instead of their respective bottoms. In each of the cubes in the group, move the origin to the bottom face to fix it:
Edit mode --> Select face --> Shift + S --> Snap cursor to selected
Then:
Object mode --> Ctrl + Alt + Shift + C --> Origin to 3D cursor
Another explanation on how to set the object's origin.

I didn't think about it, works perfectly, thanks a loot :)