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Moving Videos on Green Screen
(This is in blender cycles.)
So I have a tank animation with a green backdrop and on that green backdrop I put a road so it looks like the tank is moving on the road. But the video clip of the tank is stationary so is there a way to move the video clip across the road backdrop to make it look like the tank is moving across the road? Also is there a way to reposition the tank like rotate it to make it aligned with the road backdrop or rescale it? I wish I could send a pic to make it easier but stack exchange crashes when I do.
(This is in the compositing node editor)
So my node set up is the army tank with green backdrop in a movie clip node connected to the image of the keying node which is connected to the 2nd image slot of an alpha over node which is connected to composite. The road image is in an image node connected to the 1st image slot of the alpha over.

This may be just me but I don't completely understand -  What do you mean stationary? Isn't the tank moving in your animation?

if you can't upload an image as part of your post, upload it somewhere else and add the link to your question. Without images is hard to understand what you want to do.

If youi created the animation in blender there is no need to use a green backdrop, just use an empty background and enable film>Transparent

I didn't create the animation in blender and by stationary I mean the tank wheels are moving and stuff but the tank isn't going anywhere.

And I added the image in the question to make it easier to understand the situation. I had to reduce the quality though so stack exchange wouldn't crash.

@AustinH. Not an answer to your question, but to make screen grabs on blender, press Ctrl F3 and save the image. You can choose to save the whole screen or just the active window.

How I would do it
Your best bet for scaling, rotating, moving, and animating all that stuff would be through the VSE.
1. In the compsitor remove the green background to make adding the background easier later on using the keying node.
2. Open blenders VSE and add in your newly rendered transparent video through SHIFT+A > movie
3.With your clip selected add a transform strip via SHIFT+A > Effect Strips.. > transform. Once there you can change the size rotation and location all from the properties panel on the timeline. Your probably going to want to keyframe the movement of the tank so using the timeline put the timeline where wish and using the transformation strip you can change how the tank looks relative to the frame. Hover over the location, roation, and whatnot and then press "i" to keyframe it.
4. After you render that run through the compsitor with an alpha over node and add your pic - that should do it.
References
https://www.youtube.com/watch?v=h0F5X4b7jug
http://blenderartists.org/forum/showthread.php?261401-how-i-add-or-active-keyframe-for-VSE-blender
https://www.youtube.com/watch?v=0PZ_cxjxexM

Thanks but one issue I can't figure out now is that since the background image and video were shot with different cameras there are different dimensions, so blender tries to stretch the background image to align it with the tank and it makes the edges of the image look very blurry and glitchy looking.

using the scale node in compositing doesn't work?

I haven't tried the scale node, I will see if that works.

The scale worked successfully thanks, I have one last question. How would you change the time position of both the backdrop of a video and the main video scene? The video and backdrop both play at the same time when I want to have the backdrop play at a different time than the start of it.

Another problem I encountered is that the video looks perfectly fine but when I render it, it shows white pixels around the objects and it looks all fuzzy and messed up.

try trimming either clips before loading them into the compositor, i dont know any other way. As for your last question.. I dont know, ill look into it.

In your compositor, to mix the animation and the background image, are you using an alpha over node or a mix node?

Alpha over node.

on the alpha over node, did you check convert premul?

Yes I did convert the premul on the alpha over node.

I'm stumped, that may be a different question entirely, but if my answer helped you out feel free to accept my answer as correct, it would help me out to, but if I haven't fully answered all of your questions let me know.

Try setting the "Convert to Float" property to true for your input strip in the VSE editor to get rid of the little white pixels around the objects. (see this image: https://i.imgur.com/EiqvPk3.jpg) Also, I recommend trying out the VSE_Transform_Tools addon for positioning, scaling, and rotating in the VSE: https://github.com/doakey3/VSE_Transform_Tools


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can't subdivide face
I can't subdivide the front face in a model. I want to put more materials on the model, I used a Boolean modifier, and caused triangle faces. I don't know if that makes any difference but I need to subdivide it so badly it's getting on my nerves.
Thank you
Here's a picture of the model

it's probably because it's an ngon,try subdividing manually with the knife tool

Big ugly n-gon...  Delete it,  select then the vertices on the edge and do grid fill to go create quads.

Do you mean the whole object or the face

Related - http://blender.stackexchange.com/questions/53130/subdivide-a-face-into-smaller-faces. To be able to subdivide face there, you need another kind of topology in that region. It's up to you what method to use for that - either deleting face and recreating with GridFill or splitting existing face with Edge tools.

Boolean modifier does not ensure a "good" inner geometry. In particular when the initial mesh is already dense (as yours seems to be). To me this modifier is often a false good idea when this kind of consequences are not known in advance. As @cegaton said, the best is to delete the face and try a grid fill.

Boolean operations are a convenient way to transform geometry, but they can leave behind other problems. In this case you've generated a big and ugly n-gon (a polygon with more than 4 vertices). Ngons are notorious for deforming in unpredictable or undesirable ways. In general is preferable to work with quads.

Start by getting rid of the ngon

select the edge loop by pressing Alt while slecting an edge.

Press the space bar and type grid fill (or press CtrlF and select grid fill)

And play with the grid fill settings until you get something that does look like a grid.

Looks like an N-Gon.
To check if a mesh has N-gons do the following.

In edit mode go to face selection
Choose select from your 3d menu bar
Select All by trait
Select faces by sides
In the tool panel set the number of sides to 4(its at the bottom you may have to scroll to see it)
set the type to greater than

This will show you any face that has mort then 4 sides
Hope it helps

source: Stack Exchange

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

sort: votes


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Changes on one particle system affect other particle systems
I'm making a rabbit, so I used a particle system to make the fur. I made multiple systems by making vertex groups but I faced a problem: when I started to edit the particle system, all the systems make the same changes. For example, I clumped my first particle systems by 1.000 all of them  have the same changes. Can anyone help me thank you
Here's a picture

In the future please use a more focused title for the question, and use punctuation to make your questions clearer...

Related - http://blender.stackexchange.com/questions/10822/duplicate-particle-system-not-linked ?

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Why Alt C before Ctrl J?
I am doing this tutorial. After creating this large building (consisting of several meshes) in part 1 CG Geek is now joining all these meshes to one object. This is done in the first five minutes of the tutorial. But before he joines those meshes he does AltC. I don't understand why he first does the AltC and then joines the meshes

Related - http://blender.stackexchange.com/questions/3488/is-it-possible-to-apply-modifiers-to-multiple-objects-at-once. Using Alt+C in this case is as a workaround, fast and easy applying all the modifiers.

also related:http://blender.stackexchange.com/questions/1652/how-to-make-multi-user-objects-single-user

@cegaton I believe I am better in Questions than in Answers, LOL

I'm not entirely sure, but I can say 2 possibilities from top of my head.
One, there are curves somewhere in this model. They cannot be joined to the mesh as-is. So he converts them.
Another one, which I probably see somewhere around 6:00, is that he wants to apply his array and mirror modifiers, but cannot, because modifiers cannot be applied to multi-user mesh (if you try clicking "Apply" it will give a warning). But the trick with Alt+C -> "to mesh" does it by applying this modifier to mesh data. Note that all the objects having this data will now look different, so pay attention to all of them. I have a feeling that it was made as a safety measure, so you would not accidentally ruin all the objects having the same data by applying a modifier to one of them (because objects may have the same mesh data and different modifiers).
Clarification of multi-user data
I have a cube in the center, called cube_1. I have created the one on the left by duplicating it with alt+D (it's cube_2), and the one on the right with Ctrl+D (cube_3). If you take a look at Object Data tab, you can see that cube_1 and cube_2 have the same mesh data called "Cube", while cube_3 has a different one, called "Cube.001". Also, notice a "2" near "Cube"? That means that this mesh data has two users, which are objects cube_1 and cube_2.

When you try modifying cube_1 or cube_2 in Edit mode, they will both get modified, because you change their shared mesh data. Obviously, cube_3 has a separate mesh data "Cube.001", and modifying it will not affect two other cubes.
Now, let's focus on the first two cubes sharing the mesh data. I'll add array modifier to one of them an bevel modifier to another.

One thing to note is that a modifier, while it stays in the modifier stack, does not change the mesh data. So, even though these objects look different because of modifiers, they still have the same mesh data. If you go to edit mode, you will see the same simple cube as it was.

Now, if you try to apply a modifier by clicking "Apply" button (in Object mode, Blender disallows applying modifiers in Edit mode), it gives a warning that it cannot be applied to multi-user data. When you click the "Apply" button, you basically tell Blender to make what you see as a result of a modifier into an actual mesh data. But this same mesh data is shared by another object, and this would cause it to immediately change its shape too, depending on the modifier you applied. This could be dangerous, because it may change other objects with the same mesh data unexpectedly and ruin your scene. So, Blender avoids doing that to multi-user data.
Alt+C is more like a dirty workaround to me. It forces all the modifiers on the selected object to be applied, regardless of mesh data being shared by others. Here I did it to the left cube.

See that the right one with array modifier changed shape? That is because the mesh data is different now, as shown here:

As far as I know there are no curves in this scene. I think you are right (that he wants to apply array and mirror modifiers). Could you perhaps explain in more detail what you mean with multi-user mesh and what happens when he does ALT C ? For me it is still a bit strange

It can look strange, indeed. But, all you need to do is understand how Blender manages the datablocks.

Thanks for your very detailed and very instructive answer :) I understand that the modifiers are only applied to the object they belong to ? You say Alt C is a dirty workaround. I can understand that, but is there another way, a more "proper" way to apply the modifiers of multi-user data ?

If you care about one particular object, you could click the number near the mesh data name (in my case it's the "2" near "F", but it can be larger) and it will create a copy of mesh data. Then you can apply modifiers normally.

He is converting to a mesh from a curve I would happen to guess.
If you go back He uses Alt-c at 2:35.
I haven't watched the whole tutorial though so re watch that bit if you are not sure.
I use this command when I make a rope or something like that from a curve modifier.
Hope it helps.

no, as far as I can tell there are no curves. Then I would have understood why he does this.

He is doing it to make it all one mesh. He must have duplicated some stuff using Alt-d at some stage, this is not a normal duplicate function, if you use this and then modify one object the rest you duplicated will change.


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Animating and creating pose libraries without Shape Keys
Allow me to properly explain, step by step, in order for everyone to understand the question.
In case anyone who reads this is unaware, Manuel Bastion has released an add-on named "ManuelLab". This add-on creates Humanoid meshes you can tweak however you please. It's finalization feature uses Shape Keys.
Meanwhile, Karan Shah has posted tutorials involving creating Motion Graphics without Shape Keys or Add-ons. He also has a tutorial involving 2D cut-out characters...without Shape Keys...and with a Pose Library.
Please, do not get me wrong, I understand 2D and 3D are 2 completely different things here, especially with how Karan Shah uses the NLA editor. However, I want to set that fact beside the question at hand.
Is there any way to finalize ManuelLab generated Meshes, with their skeletons intact, without using Shape Keys? I believe there is something to be gained from the mixture of what both of these artists and developers have created. This sounds like a tall jump or too steep a step, but I am no less hopeful.
The pose library involves the use of multiple layers to Move objects throughout.
Edit by request:
http://www.manuelbastioni.com/download.php
http://tutsplus.com/authors/karan-shah
http://www.tutsplus.com/authors/karan-shah (Check the 1st 4 tutorials at the top, at the time this post is edited.)

Could you please edit question to provide links to addons / tutorials?

Post edited, check it out when you have time.

I think the answer is simple : you may need up to one bone per vertex to obtain the same accuracy as shape keys.
About Karan Shah : he uses UV warp modifier which is purely based on the UV mapping. So that does not change the 3D (or 2D) geometry. Also, in this approach, you cannot mix the effect of two bones (and shape keys can be mixed).
If we want to compare shape keys effect on the face of a Manuel Lab character to UV warp effect for Karan Shah, you'll see that for each shape keys combination (for ML), you may need one texture part (for KS).
After that, maybe something new could be invented... I don't know.

That helps. Would there be any way to make a Pose Library with shape keys? Sort of like game command bindings?

@Darknaviexe, what do you aim to do ? This question is the opposite of your initial question...

I want to generate a pose library, but for 3D models, not just 2D pieces. I previously believed I could achieve this in the same manner Karan Shah did, but I find I would need an approach enlisting the use of Shape Keys. I believe this starts with recording pose animations, just like using a Dope Sheet, NLA editor and action editor, featuring keyframes, but I also want to make sure clothing follows the general movements, requiring Gradient Weight Painting.

@Darknaviexe, shape keys cannot replace bones, as shape keys are not relative to other shape keys (but bones are relative to their parent). So you may need a lot (really a lot) of shape keys to 'redo' all relative positions of the bones. Also shape keys do not rotate (the transition 0 to 1 of a SK is linear). But the two can be used in complement (for instance here : https://www.youtube.com/watch?v=f3JWNIkwBZ8).


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View image without any interface
Is there a way to view JUST the rendered image while making the interface disappear (a la Photoshop fullscreen)?  I want to see literally only my rendered pixels and zero Blender interface things.  Thanks!

actually the whole interface can be removed from ANY view, not only the Image Editor. Place your mouse cursor over the area in question, then hit Right Alt+F10 (maximize view and remove interface) and then Alt+F11 (remove title bar and also task bar on Windows or dash on Linux). To get back, you can use the same keystrokes, or move the mouse cursor in the top right corner of the window, until an icon appears.

Not exactly with zero interface, but if only the info bar is little enough then  you can change the viewport to the uv/ image editor:

Then select render result from the list of available images.
If you want to get the properties panel off- screen, then just press Shift+Spacebar to toggle it and clean up the view. You can pull the footer down as well if you wish.


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Problems after separation part of a mesh
I am learning how to destroy a building with this tutorial

The part of the building that gets smashed is separated from the main building (one large mesh).

Somehow some artefacts have been created.

What is wrong and how to repair this ? Or better go back and separate the "smashed part" again ?
Hmmm ... now I notice that there are some problems with that left column too .... ????

It looks like a traditional normal issue, your faces are turned to the inside of the object.
It actually happens in both your objects, the 'shard' and the rest of the building.
Enter edit mode, select one of the darkened faces, press Shift + G to select grouped and choose Normal to select faces facing in the same direction (check the selection for unwanted non-darkened faces and deselect any that don't apply)
Then press Ctrl + N to make normals consistent across the surface.
Repeat for the red frames on the building too, they also seem to be facing inwards.

thanks I will try. What is causing the "normal issue" ? I did recalculate but that did not help

In computer 3D models faces always have a front facing side (and a backface). It is mostly irrelevant for rendering, but can cause issues while modeling, or with modifiers, Boolean operations and viewport display. Depends on how you modeled it or which technique you used to 'break it apart'. Faces often get incorrectly flipped with certain operations, modifiers, through incorrect modeling procedures or often simple user mistake. It's mostly harmless, and recalculating them often fixes the problem.


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How do I reveal the "Diffuse and Transparency" option in Cycles Render for Import as plane (png)?
Currently I can only see the diffuse and emission options. However, on tutorials such as the screenshotted one, it requires that I have other options available. I added the same addons as in the tutorial, and yes, I am in the cycles render engine.

Here is my screen, currently.

Thank you for all the helps.

Enable the box that reads Use Alpha

those 2 options were probably removed because they are redundant , the tutorial is using a blender version 2.75,the equivalent of Diffuse & transparent is  selecting "Diffuse" and enabling the Alpha Checkbox.

Those options are gone.
The way to do transparency is to enable Use Alpha

And then choose between diffuse and emission as the shader.


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Strange residues after separation of mesh
I have modelled this large building (see below). After joining all the elements of the building to one big mesh I separated a part of the building. In this building there are floors and these floors / planes are also separated now. But you see in the encircled area that somehow there are residues ( "borders" of those planes). What are those residues ? It looks like that these residues are the borders of those planes / floors ???

This is the blend file before separation

OK, I think you were in face selection mode, and you have unconnected edges. That is what you are seeing now. Because the edges were not part of a face they will stay unselected when using face select mode.
PS You also have a LOT of duplicate vertices, 83,559 to be exact, Not related to this, but probably not going to help you.
To delete the unconnected edges, switch to edge select mode, and select one of the loose edges.
Then from the 3D view header Select > Select Similar > Amount of Faces Around an Edge, or just simply ShiftG then A. Now delete all the selected vertices with X > Vertices, or Delete > Vertices.

I will try your solution but how are these residues created ?

I dont know how you made the mesh, but probably at some point (maybe when you were making the window?) you just accidentally duplicated an edge. Then after applying all array and mirror modifiers, it  adds up to a lot of duplicated edges.

thanks. your solution works. !!! Also important that I know what was causing these problems

maybe I am doing something wrong. When I do Shift G and delete the vertices also some holes in my mesh are created. So the residues are deleted but also some parts of the mesh that should be kept.

do you know what I am doing wrong ?

Don't know, in the file you uploaded first (large_city_building_003) it works for me. Are the meshed different in different versions of your file?

do you still have that file ? I think I have not

have you tried with the file I uploaded to Blend Exchange ?

Yes I do still have the file. I just tried separating a piece of your building from the new file, and it works as expected. The only pieces that remain in the hole are the floor.

Let us continue this discussion in chat.


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Make Mist pass skip semitransparent objects
I am having problems with the Mist pass. I have search other questions but didn't find the answer.
As you can see, I got an ocean (left) and a "river" (right). Don`t mind about the river disappearing towards the right, I need that way but doesn´t affect my problem (but I wanted to keep the settings as I have in the big project).
When trying to get the Mist pass, both objects are semitransparent, as you can see here:

Also the Z pass gets crazy:

I think is because they both have glass and transparent material, and also volume absorption.
The sun is 0.8 in size and 5 Max bounces.
So, the question is: How can I get the Mist pass "skip" the transparency settings of both objects?
Thanks in advance!

Create a new render layer in which the material is overriden by some material that has no transparency, and enable mist for that render layer. Then use the mist pass from that layer to combine over the other layers.

(click on the image to enlarge)

Thank you cegaton! Perfectly resolved and in an easy way, without having to do much extra work. Maybe in Blender's updates they will make it even more easier!

As long as it doesn't affect your other render passes, you can go to the View Layers Tab > Passes > Data set the Alpha Threshold to zero.
This will effectively make the Depth Pass ignore the alpha of all objects that are transparent or translucent to any degree. It will treat them as solid objects.
This option is only available in Cycles, AFAIK EEVEE already ignores transparency for Depth passes.

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Baking of several particle systems
I am doing this tutorial. have two particle systems in my scene (for the same object). One particle system is for generating shards of glass and the other one for smoke & fire. I should say that I should do two bakes, one for each particle system. Is that right ?
I think I am a bit confused about the "baking" options.
A) Particle System "Shards of Glass". As I said I have one particle system for generating shards of glass. The particle system uses "shards of glass" objects. In the "particle system" box there is an option to bake. This is to bake the emission of shards of glass ?
B) Smoke and Fire Simulation. A cube is used for the "domain" and a  particle system for the "flow" of smoke and fire. When dealing with smoke and fire in tutorials the baking is done in the domain (but why not in the particle system)? Why is that ? Why is the baking not done in the particle system (the particle system emits the smoke) ?
I guess I have a basic non-understanding about all these baking options.

First off, particle systems are responsible for emitting particles, they have nothing to do with any smoke or fire simulations; on the other hand, smoke simulation is used for emitting smoke, not for particles. Particle system can be used as emitter for smoke (instead of actual mesh), - but their data is different and you can't bake smoke simulation from particle system panel (unless baking everything, see below).
Hence there is Bake button for baking in their options. It will work per each physics simulation - each smoke / fire sim will be baked from its domain, particle systems - from their options per each particle system, same for dynamic paint etc. With this way you'll bake them one by one.

The only way which is independant on these options is to bake all physics at once - with Bake All Dynamics button which will bake everything you have to bake in scene:

Bake All Dynamics
      Bake all physics systems in the scene, even those of different types. Useful for baking complex setups involving interactions between different physics types.

Note that it may last longer than you expected (because of amount of data to compute).

I understand that the baking of smoke/fire is done in the physics domain. But this "emission of shards of glass" ...does this need baking ?And if yes, is it done in the particle systems box ?

A second question ... "bake all dynamics" is an option for one particle system. Does this bake all physics, also for other particle systems ? I guess the answer is yes, but it is a bit strange ...

Can you give an example of baking a particle system that is not a physics simulation (like smoke/fire) ?

@OldMan baking is needed for any type of simulation used in the scene. If it isn't done it will be calculated while playing animation (hence slower / increasing possibility of crash etc)  If "shards of glass" were done with particle system , then find that particle system making those shards and bake from there - you'll bake only physics responsible for those shards of glass. If any other system depends on those shards, that system will be needed to be calculated. Your second question - yes, for all other particle systems (and not only). Not sure what you mean by the last question

by the way (maybe the is a new question) ... I just bumped into this question http://blender.stackexchange.com/questions/56514/the-second-particles-system-not-working-properly?rq=1 answered by you. I understand you can apply a particle system in conjunction with an explode modifier. In the tutorial that I am doing the particle systems emits shards of glass and not pieces created by the explosion. What is best ?

ok ... I will make another question. I still don't complete understand the baking. A) why is the baking for smoke/fire done under the physics tab and not under the particle system tab ? B) a bit strange that when you click "bake all dynamics" all bakes are done, also for other particle systems ?

A. When baking with Bake button it must be done per each physics simulation. As smoke sim settings are in physics tab, you control them from there. And bake from there too. Particle systems have their control panel in their own tab; and they are being baked from there. So for object with 3 particle systems and smoke sim you'll have to open 1st system, hit Bake, open 2nd, bake there, open 3rd, bake there, then select domain, open Physics tab for it and bake from there. B. in this case all these operations are done for you automatically (has disadvantages too)

@OldMan In other words- baking particles mean pre-calculating only particles. Baking smoke sim based on particles means only baking smoke sim (you'llbe able to change system's settings). It's enough to bake only smoke sim as generally particles system takes far less resources than smoke.

I think now I get it. Thx


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How to bend the bendy bones found in Blender Builds recent to 2.78
I checked the Wiki, I checked the website of the original creator, I am still lost. Does anyone know how to make Bendy Bones Bend? I have added segments, I am not sure where to go next. Anyone know how? Please, I just want to use it.

I guess they bend already. Can you please verify that you are displaying them correctly? They only show up in BBone display mode:

B-Bone display, check. Segments, 9. Rotating and moving, not bending. I still seem to be missing a vital detail. Edit mode, not sure where else. Trying pose mode, too.
Okay, found it. Curve XY offsets, I am blind. Thanks!

As it turns out, I was not paying attention to every detail. Offset XY and settings next to it curve and bend the bones.

Since you already added the segments to the B-Bone, you can use the bendy bone functions under the bone tab. there are some useful tools if you are sure staying in the B-Bone shown mode, In X, Out X, In Y, Out Y, etc...
and use that with keying frames you are gonna see how amazing it will be. :P
have fun!

An image showing exactly where the settings you mention are could be useful.


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Mirror modifier gap not to merging because of multiresolution modifier
So I was creating this rhino and when I wanted to use the mirror modifier on it, however you could see a large gap between the two parts.
In edit mode the vertices are merged together but in object mode there is a gap.

The Multires Modifier has to be the first one in the stack, you cannot move it anywhere else. That's why Blender always first evaluates MultiRes, then the Mirror. The trap you're falling into here is that with the Multires you very likely deformed vertices in the center line, which moves them away from the symmetry plane, and thus the Mirror doesn't merge them any more.
A usual way to avoid this is to apply the Mirror before you even add the Multires to the mesh, and sculpt the mesh using X-Mirror, so all sculpting happens on both sides of the model.
However there might be a quick fix: Try increasing the Merge Limit until the center line merges again, and then check the rest of the model if vertices accidentally merge there as well. If you're lucky, the deformation has not been too destructive yet.

Thanks for the answer i tried the quick fix but it didn't fix the whole gap.So i guess i just have to start over.

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Particle system on sapling addon tree forces the leaves to be impaled
I am currently watching a tutorial on YouTube "How to Create Low Poly Nature - Blender Tutorial" (at about 23/25 minutes).
The sapling addon is doing great, so is the weight paint view, but when I add a new particle set, go to hair, set emissions to 20, and do everything else that the "CGGeek" does, my leaves are impaled, using the center of my .png texture instead of the tip.
I must have repeated the steps in this video half a dozen times for this one section.
Here are some pictures of my screen:

Your problem is the leaf's object center. Objects are placed in the scene/particle system according to their center. See my answer here on how to fix it http://blender.stackexchange.com/questions/57812/using-unity-tree-editor-with-blender-trees/57817#57817

Thank you so much. This fixed everything. Now my sapling is looking as beautiful as the day it was planted. Or something. It looks good.


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Bake Taxtures to one Image
I have a mesh which has many UV maps and a lot of textures applied to it. Everything is in one material.
Is it possible to Create a final UV map And bake the textures together in one big image?

Related: http://blender.stackexchange.com/questions/15510/possible-to-bake-texture-to-new-uv-map

It is possible. I have the similar case as yours. I've got a model, which consists of multiple separate parts. Each part has its own single material and own textures.

First join the meshes together with Ctrl+J.

Next create a new UV Map (press the '+' button in the UV Maps panel of the Mesh Data header and add a new image in the UV Editor window.

Unwrap your mesh with U-->Unwrap.

Go to Render header, set the bake mode to Textures and hit the BAKE button. It will create one big color texture map from the all textures you've apllied.

EDIT:
Here's a case, where object has one material and multiple textures applied to each face of the cube (via Unwrap-->Project from View(Bounds)). Every face has its own UV Map slot.

I then marked seams for the cube, unwraped it and created new UV Map for it (called 'all'). Then baked the Textures. And here's the result:

Hope it'll help you.

In my Case its a single mesh. If you join meshes together with ctrl+j you effectively do not have a single Material anymore. Which in my case I do.
The Probelm I have is how to enable specific UV Maps for Specific Textures on one material and bake it together.

I've updated my answer. If it doesn't help, please provide more information about your textures setup or maybe post your .blend via http://blend-exchange.giantcowfilms.com/

You can choose from UVMaps using "UV Map" node (under input in material node editor), or you can use "Atribute" node and connect vector output to texture and write UVMap name to it.
Also check Texture Atlas which been develop for baking textures from multiple object to one. It create one object and don't change your original objects. Here you can easily make new UVMap for baking textures to it.


text:
Scale and stay at Z position
I have a cube positioned at Z-axis = 0 like this

Now I scale the cube 3 times and then I get this

How to scale that the cube is enlarged 3 times along the Z axis and stays at Z = 0 ? Like this

You may put the origin point at the bottom of the cube (in the same place where your cursor is in the third picture) and then scale. In Edit Mode place the cursor at the bottom of the object and then in Object Mode press Shift+Ctrl+Alt+C--->Origin to 3D Cursor.

You can choose "Pivot point" for manipulate with objects. Default is "Median Point", which is Origin in your case. You need switch Pivot point to "3D Cursor"


text:
Why are there dfferences between Textured and Rendered modes?
I have assigned a material with an image texture to this cube (I think) and when viewed in Texture mode I see this

When viewed in Rendered Mode I see this

This suggests I did not properly assign the material but why is it visible in Texture mode ? I know why I get this purple color but the question is why I see this purple color in Rendered Mode and not in Texture mode (this is why this question is not a duplicate imo)

How did you apply the texture? How is the material applied? Cycles or Blender Internal? Could you edit you question and provide more info, like a material setup screenshot? It may happen that you are just seeing your UV unwrap in the viewport, and didn't properly create a material with a texture.

this could be the case  .... but how is it possible that I see the image texture in Texture mode and not in Rendered mode ?

Possible duplicate of Why are all the textures in my file pink?

Texture mode shows unwrapped textures even if they aren't applied to a material yet for preview purposes

It appears like you have moved the texture after you brought it into blender. You need to relocate the texture. When blender renders it loads the texture from disk (and is unable to find it causing the purple). The material view is using the copy in memory. When the file is saved and reloaded the material view will purple as well.

yes but can you explain why the image texture is visible in Texture mode and not in Rendered mode ?

It is visible in textured view because the texture is still in memory. Texture are stored in memory on image load to improve performance. This means that if the file is moved or adjusted blender doesn't update. You still see the texture. This memory only gets emptied when blender is quit. Rendered mode does not use memory and instead attempts to read from disk, is unable to find the file, and shows as purple.


text:
Need Help Adding a UV Mapping on my Dragon for Unreal Engine
I'm to unwrap my dragon model in order to add a UV mapping on it, but the mesh so complex that it's actually making Blender crash if I do the entire model. Basically, I'm trying to unwrap the model, but also have it displayed where it is easiest for me to understand and I would like figure out how to place it over where I have colored the model. I already UVed the eyes, and the wings and body are separate meshes (so are the eyes and gums and teeth, but they're merged with the body mesh).
Here's the Blender file

Here's a photo of the dragon (normal and wire mode)

Hello, I have tried and did not have any problem unwrapping the body. However, in order to have a good UV map, you may mark seams on your model (like if your mesh was a cloth from which you mark the seewing).

I tried making seams but it seems to make it even harder to see the mappings (I tried this on the wings)

For some reason, I can't seem to get the UV textures to display on the mesh.. rendering doesn't help it either


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How do you fix compositing leaking in Blender Cycles?
So I created a Minecraft Animation Scene with a melon in a basket. I did some compositing for another scene to make the melon glow but from a different camera angle you can see the glow from the melon leaking through the entire basket when the glow is supposed to stay inside of the basket from the melon. How do I fix this?

If this is an animation, then you can keyframe your Screen fac slider

You have the render layers putting out the z-depth.  Use that in a Color -> Z Combine node.  Tweak where everything goes until you are happy.  This will either show or hide elements of your scene depending on whether they are in the foreground, or behind something.


text:
Image delineation
Is there a quick way in blender that I can use to delineate all the boundaries of the drawing and make them appear on a uv sphere, making it interactive in blender?
P.S. I'm in cycles

Hello. What do you mean by "interactable" ? also is it mandatory to have the texture on a sphere ? Can you explain a bit more editing your question ?

I meant interactive :\ I've adjusted the question

Your question is unclear. What boundaries do you want as a mesh? Guessing you want  the boundaries of the drawing as a mesh you can use GIMP.
Open up the image in GIMP and select all lines. This is best done using the 'Select by Colour Tool'. Having everything selected, you have to click on 'To Path' in the Select Tab. Then go to the path window (by default on the right hand side) and right click your path and select 'Export Path'. Name your file *.svg. Then activate the addon 'Import-Export: Scalable Vector Graphics (SVG) 1.1 format' in your Blender user preferences. Save your user settings if you want it to be activated on startup from now on. Then go to 'File' -> 'Import' -> 'Scalable Vector Graphics (.svg)'. Choose your file and press 'Import SVG'. Now you have your path imported as a curve. In order to convert it to a mesh press Alt+C while hovering over the 3D View with your mouse. Then select 'Mesh from Curve/Meta/Surf/Text'.

Your response is almost perfect, it's just the last part what I don't want, the texture should appear on a uv sphere. My bad!

If you mean that the mesh should appear on the sphere the way the texture does I can't think of a definite way of doing so. I'd fiddle around with the warp tool (press 'Space' and type in warp in edit mode or mesh ->transform ->warp). Note that it uses the 3d cursor as reference point and not the object's origin. It also takes your POV into account. As an example you can turn a subdivided plane (2 blender units * 2 blender units) into a sphere by warping it 180° from front view and 360° from right view. The mesh has to be 1 blender unit above the 3d cursor. I hope that that's what you want.

@DavidS., for the sphere aspect http://blender.stackexchange.com/questions/24043/how-to-animate-morphing-a-rectangular-plane-into-a-sphere or http://blender.stackexchange.com/questions/52904/wrap-curve-around-sphere/53172#53172


text:
Cycles Noise Issue - No matter what I do it won't go away
So I am making a Minecraft animation. I have been trying so hard to figure out how to get rid of all the noise though in my scene. I want the shadows and objects to look nicer and smoother. I have tried almost everything to get rid of the noise. In Light Paths I set Bounces Max and Min to the same values, the resolution is 100% at 1920 x 1080, I have adjusted the clamp indirect to many values such as 1, 3, etc. I am using an HDR image to light my scene and I heard HDRI's can cause it if you don't have a high enough Map Resolution in the settings so I even set the Map Resolution to 6000 when 2000 should be enough. I even tried rendering the image at 1000 samples and it still wouldn't go away when 200 samples should have been enough. I heard that despeckle nodes can help but I don't want to use one because they can greatly reduce the quality of each image.
I circled some of the noise spots with a red circle.

If you are using an HDR environment enable Multiple Importance sampling

I am using that.

That is what I used for the image you see in my question. Still doesn't work.

Please post images of the settings used.

Added settings images.

Possible duplicate of How to avoid noisy renders in Cycles?

Let's walk through troubleshooting this, shall we?
Ok, first, where is the noise in the image? You might notice it does not appear in the sunlit areas, just the shadows. So we can eliminate that it is coming from the first hit (camera > surface) or evaluating the brightness of our main sun light. We can also observe it does not appear solely along the edges of shadows, rather it is spread throughout the shaded areas.
The fact that it is spread evenly in the shaded areas but does not appear in the sunlight tells us it is coming from one of the sources of fill light. That could be an additional light source (like a skydome/HDRI or a fill light) or it could be from global illumination. Or perhaps it is a reflection of fill light. How do we find out?
The answer is in the render passes. Over in the layers panel, enable the direct and indirect (don't worry about the color pass) for glossy and diffuse. Which of the 4 passes contains the noise?
Diffuse direct - Your source of noise is the direct light evaluation itself. This usually comes from HDRIs. Make sure the "multiple importance" option is enabled and the resolution is set to the # of pixels on the longer side of your HDRI map. For example, a 2048x1024 HDRI you would use the value 2048. If you are using the branched path tracing integrator, you can increase the world sample value to send more rays towards this problem for each primary sample.
Diffuse indirect - Your source of noise is global illumination/diffuse reflection: light scattering off a surface and illuminating another surface. Check that you do not have surfaces with excessively bright diffuse colors (diffuse color is the surface albedo, it should never be 100%/1.0. Even 90%/0.9 is uncommon, that's why the default is 0.8). Additionally, try disabling caustics in the light paths panel. These are harder to resolve than normal scattered light. Finally, the more diffuse bounces you have, the greater than chance of a ray taking a "funny bounce" and returning an anomalous value. Reduce this under light paths, many scenes the difference for any values over 2 isn't really noticeable unless you compare with a 2-bounce render. If you are using branched path, increase diffuse samples in the render panel to send more rays to this problem
Glossy direct - Your source of noise is reflections hitting varying parts of a textured light. This is more or less the same problem you'd see in the diffuse direct pass. The solution is the same, check MIS is on for the world and set to an appropriate resolution.
Glossy indirect - Your source of noise is reflections of other objects. Blurry reflections mean a ray can take off in a variety of different directions. Depending on which one it picks, it can catch different objects in the reflection. The final blurry reflection is an average of all of these, but until your trace enough rays for the situation to average out, you get noise. Try using the filter glossy option to contain the possible variance(it limits the shininess as a ray bounces more times), and like with diffuse avoid non-emission shaders with extremely bright colors. You can also lower glossy depth under light paths to try and contain the possible results, although can lead to black reflections if set to low. If you are using branched path, increase glossy samples in render settings to send more rays to this problem

So in the renderlayers under passes just enable diffuse: direct and indirect then glossy: direct and indirect?

I did all the steps you said and I am still getting similar noise results.

Enabling the passes will not fix the issue, it merely lets you see where the problem is. My answer lists some steps to try depending on which pass you see the noise in.

I see it in the shadows.

What happens if you see the problem without any of the passes checked?

Sorry if I'm not being clear. You will see it with all the passes, because the combined pass is just that - all of the passes combined. The individual passes will show only certain light contributions, so you can nail down which ones are causing the noise. You may also find these links helpful (for Arnold, not Cycles, but the same concepts apply): https://support.solidangle.com/display/ARP/Removing+Noise https://support.solidangle.com/display/ARP/Removing+Noise+Workflow

I believe the noise only goes into the shadows so what do you think I should do?

I'm not sure what to tell you that isn't in my original answer. "Shadows" aren't a distinct thing, they are regions with less light. The problem is likely to be with what light is present in the shadow than with the shadow calculation itself (that usually shows as noise along the shadow edge).
It's impossible to say without doing test renders, but my guess is you'll need to just increase samples further, or reduce the brightness of your textures so they reflect less light.

I tried everything you said and it still won't work. The sampling barely works but I don't want to have over 1,000 samples per image.

@JtheNinja Nice answer! One question though, you say to set the resolution of the multiple importance sample to the long side of the hdr. Why is that? What if the hdr is not a power of two? If I use a 8k hdr do I really need to set the resolution to 8192? What if a bigger hdr? (blender's max is 8192)

The resolution of the "importance map" that tells Cycles where the bright regions are. Matching the image resolution makes sure this map is accurate. It does not need to be power of 2. If you use an 8k hdri, I'd recommend using a downscaled version for lighting and only using 8k for camera rays (use light path node). Might want to make this its own question if you need more info.

You're mistaken in thinking that 1000 samples is "a lot." Unless you have "square samples" turned on, then 1000 samples is really not very many.
For many scenes (especially complex stills), I regularly render hundreds of thousands of samples before the noise goes away.
The only REAL way to get rid of noise is to render enough samples. It's a statistical problem. Cycles has to "find out" what color a given pixel is by testing (sampling) it. It has to take a lot of tests because there are a lot of contributing factors. Cycles will (sort of) average each sample for a given pixel, but until Cycles has taken enough samples of a pixel that pixel's color will only be approximately the correct color.
There are ways to mask, disguise, or otherwise hide the fact that the color is only approximate, but all of those techniques necessarily sacrifice accuracy and quality. There are already a number of good answers that describe what noise is, how it's caused, and how to mitigate it. You should read them. They will be helpful.
One thing that will really help you render more samples is to bake the lighting for anything that doesn't move (and only if none of the lights move). Because none of that data for those objects changes from one frame to the next, it's possible to make it into a texture. When you use that texture on an emission node for that material, it looks exactly the same, but renders WAY faster (basically, it's just doing a lookup on the texture, without having to do any calculations). Since those baked objects render faster, you will be able to render more samples in the same amount of time. This will make the objects you CAN'T bake less noisy.
BlenderGuru has a good tutorial on baking.


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Connecting separated edges

I have a problem with the Blender sculpt mode. If I extrude one cube after the other, they're not connecting each other. That becomes a problem, if I want to start with the sculpt mode. I add an subdivison surface and their becoming to two kind of single parts(picture red), even if I join to the simple mode, I can't sculpt them because it's building a gap. Is there a way to connect these two parts (red) together?
Thanks for any help!

Try using remove doubles in the tool shelf (T) while having the part selected where the edges are separated. You can increase the merge distance beneath the tool shelf. If this doesn't give you what you want you can do it manually by zooming in to the edge that you want to correct in vertex select mode and selecting the two separated vertices. Then press Alt M and choose the option that's the best for you, probably at center.
Side note: Please make clearer question titles. 'Question about Sculpt Mode' is pretty general and nobody really knows what your question is about. Something like e. g. 'Connecting separated edges' would be better. Keep that in mind.

This seems to be the classic Blender beginner's error which everyone of us made at some point while extruding.
Your Mesh seems to have "interior faces" - faces that are inside the mesh. To spot and get rid of them easily, Tab into Edit Mode, in your 3D View go to the Menu -> Select -> Select all by Trait -> Interior Faces.

If there are any, they will be selected. Now, hit X, select "Faces" and your model should be clean.
To avoid the creation of interior faces you can hit CtrlZ (undo) after you have canceled an extrusion.


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Select mirror: Could it add to the selection
Is there any way to make "Select Mirror" add to the selection, rather than just drop the previously selected?

Open up the operator part of the Toolshelf Region or press F6. Then click on the Extend check box.

authors: Лариса Румянцева


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Select Active Rigid Body Parts
I am doing this tutorial and try to learn how Rigid Bodies work. I have selected the center parts of the brick wall and made them active.

Somewhat later I want to reselect the active parts but how to do that ? How can you reselect the parts that you have made active ?

You could simply group them once selected the first time (ctrl+G), then use the outliner to find them again (set the search option to 'groups')... but is your question about to reselect them without having anticipated that ?

Yes, your answer is a good tip for the next time. But my question was how to reselect them without having anticipated that ? So are the "active" bodies selectable ?

Is your question about how to find which object does have Rigid Body physics added (assuming there are a lot of them and only several have modifier added) ?

@MrZak My question is about the brick wall.Some parts are "passive" rigid body objects and other are "active" rigid body objects (the ones that get smashed). The question is how to reselect the "active" rigid body objects

I see now; yes, probably the most efficient and may be the only way to do that is by scripting.

@MrZak OK. Batfinger created a script, but I have no Python knowledge. Don't know what piece of those scripts I should import in Blender and how to do that ?

@OldMan, I undelete my answer (which is in the same principle of the better one given by batFinger), just in order you see how to use the script. The difference is once you have run the script, batFinger solution give you a menu. Mine simply selects the wanted objects. Tell me if this is ok for you, then I will delete it again.

@lemon the solution of batFinger works really nice. But I am also very happy with your suggestion to use Groups next time. Where can I read more about Groups ?

@OldMan, surely in the documentation https://www.blender.org/manual/editors/3dview/object/relationships/groups.html. As said here, groups are only a way to organize your objects, logically (so with no impact on the other aspects)

@lemon Thanks. Do you know perhaps how I can install the batFinger script as a permanent extension of my Blender application ? I have zero Python know how

@OldMan, I am not sure but you may try to open a new Blender session, add the script and run it then save your startup file. Not sure it works for this script. But ask batFINGER he may know that far better than me

Operator
As a select physics  operator.
Edit update for 2.8

bl_info = {
    "name": "Select RigidBody Objects",
    "author": "batFINGER",
    "version": (1, 0),
    "blender": (2, 80, 0),
    "location": "View3D > Select > Object > Rigid Body Object",
    "description": "Selects Rigid Body Objects",
    "warning": "",
    "wiki_url": "",
    "category": "3D View",
    }

import bpy
from bpy.types import Operator
from bpy.props import EnumProperty, BoolProperty

class OBJECT_OT_select_rigid_body(Operator):
    """Select Rigid Body"""
    bl_idname = "object.select_rigid_body"
    bl_label = "Select Rigid Body Objects"
    bl_options = {'REGISTER', 'UNDO'}
    rna = bpy.ops.object.select_all.get_rna_type()
    action: EnumProperty(
        name="Action",
        items=tuple((i.identifier, i.name, i.description)
            for i in rna.properties['action'].enum_items),
        default='SELECT',
        )
    enum  = bpy.types.RigidBodyObject.bl_rna.properties['type']

    items = [(o.identifier, o.name, o.description, o.icon, o.value)
              for o in enum.enum_items]
    type: EnumProperty(items=items, name=enum.name, description=enum.description, default=enum.default)
    extend: BoolProperty(name = "Extend Selection", default=False)

    def execute(self, context):
        scene = context.scene
        obj = context.active_object

        rigids = [o for o in scene.objects if o.rigid_body
                    and o.rigid_body.type == self.type]
        if not self.extend:
            bpy.ops.object.select_all(action='DESELECT')

        action = self.action
        if rigids:
            if action == 'SELECT':
                select = True
            if action == 'DESELECT':
                selection = False
            if action == 'INVERT':
                select = not obj.select

            if obj not in rigids and not self.extend:
                scene.objects.active = rigids[0]
            for o in rigids:
                o.select_set(select)

        return {'FINISHED'}

# Registration

def add_select_menu(self, context):
    self.layout.operator_menu_enum(
        OBJECT_OT_select_rigid_body.bl_idname,
        "type",
        icon='PHYSICS')

def register():
    bpy.types.VIEW3D_MT_select_object.prepend(add_select_menu)
    bpy.utils.register_class(OBJECT_OT_select_rigid_body)

def unregister():
    bpy.types.VIEW3D_MT_select_object.remove(add_select_menu)
    bpy.utils.unregister_class(OBJECT_OT_select_rigid_body)

if __name__ == "__main__":
    register()

Install addon as shown here https://blender.stackexchange.com/a/1689/15543
To enable.

Alternatively (aka old answer)
A simple script to add a toggling property to the object select menu. (Avoids setting up an operator, but end up with code useful to create an op later if needed)

Showing the checkbox on menu
If toggled from false to true will select all active type rigid bodies.  The other way will deselect.
import bpy
from bpy.props import BoolProperty

def select_active_rigids(self, context):
    # deselect all
    if self.select_active_rigids:
        for o in self.objects:
            o.select = False
    rigids = [o for o in self.objects if o.rigid_body
                and o.rigid_body.type == 'ACTIVE']
    for o in rigids:
        self.objects.active = o
        o.select = self.select_active_rigids
    return None

bpy.types.Scene.select_active_rigids = BoolProperty(update=select_active_rigids)

def draw(self, context):
    scene = context.scene
    layout = self.layout
    text = "Deselect" if scene.select_active_rigids else "Select"

    layout.prop(scene, "select_active_rigids",
                text="%s Rigids" % text,
                toggle=True)

# hit F8 to clear from menu (reloads all)
bpy.types.VIEW3D_MT_select_object.prepend(draw)

For scripters: an example of defining a context property.
import bpy
def selected_active_physics_objects(self):
    return [o for o in self.selected_objects
                if o.rigid_body
                    and o.rigid_body.type == 'ACTIVE']

bpy.types.Context.selected_active_physics_objects = property(selected_active_physics_objects)

'''
Example Console Output
>>> C.selected_active_physics_objects
[bpy.data.objects['Cone.001'], bpy.data.objects['Cone'], bpy.data.objects['Cube.001'], bpy.data.objects['Cube']]
'''


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How can I find my particle system?
I feel very stupid asking this .... but uh ... I have this brick wall and I gave one of those bricks a particle system. But now I don't know any more which brick. How can I find the brick with the particle system ?

Open the Outliner
Switch it's mode to Current Scene
Use the search box to search for ParticleSystem by default (or whichever other name you used, if you manually renamed it)
You object with the particle system should come up in the list bellow
Just click on its icon and it should select the relevant object in the 3D view


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Rigid Body and Invisible Object Collision
Let us assume I have a brick wall (rigid body) that I want to get smashed with an object (in a rigid body simulation). I want this object to be invisible in the render. Is that possible? How do I do that?

Via shaders? Couldn't you just turn up the transparency or use a Transparent BSDF?

As of now, I see no reason why you couldn't add a Transparent BSDF shader to the smashy object.
View:

Render:

Animation with transparent smashy thing:

My .blend file:

Also, as lemon points out, in the Properties panel > Object tab > Cycles Settings dropdown, you could uncheck the Camera checkbox. If you follow this course, though, you will have a disembodied shadow.

As Nathan Craddock adds, you can also turn off Render Visibility in the Outliner.

You can also simply disable the camera ray visibility in the Cycles settings of the object

@lemon Very true. Added your advice.

You can also turn off renderability in the outliner.

@NathanCraddock Thanks! Added that in, too.

@NathanCraddock If I turn off render visibility I will have my object not rendered, do I ?

@OldMan it just won't be visible. It will still interact.

@NathanCraddock I tested it and you are right.  I always thought the object was excluded from the render


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Containing a hair's shape within a mesh, even with vertex groups: Is it possible?
Is there any way to contain the shape of hair within a mesh? Would it need vertex groups for more than density? I want to put hair inside a mesh, make the mesh invisible while containing the hair, then have the hair follow along with the shape of the mesh.

Hello. Which kind of shape do you want ?

I want to make a wig mesh, then fit the hair inside of it, forcing it to conform.

so a wig but any kind of shape ?

Yes, and that it shapes and contains hair particles.


text:
Why OSL script is not showing the result?
I tried to copy the source of the Separate RGB shader but not getting the same result as the original Separate RGB node.

Top Left: A copy of Separate RGB source taken from blender repo.
Top Right: The texture used as mask.
Bottom Left: Plane with material using the the script to get the B channel.
Bottom Right: Plane with material using the original Separate RGB node to get the B channel.

Why is it not working using the script?

Have you enabled Open Shading Language in your Render options?

That is it. I thought that's the default since the built-in shaders have . osl extension. The result does not show in material view mode though; it needs to be rendered. Thanks.

The material view actually tries to convert the cycles materials to OpenGL in the background, and use that in the viewport. It cannot do that for OSL nodes sadly.

note that GPU can't handle script nodes :/ (the "Open Shading Language" option does not shows up)


text:
Why are these fluid particles not being blocked correctly?
I am doing this tutorial. I have this cylinder / lamp and an emitter plane (see arrow).

Just below the emitter plane I closed the cylinder with a face. And checked Size Deflect. Also the cylinder has Collision marked. Now the fluid particles should be blocked by the cylinder / lamp ? But as you can they are not. What should I change to block the fluid particles by the lamp ?

I am not very skilled at that so I wont give an answer, but you have a parameter to increase the precision of the simulation. You can find it in the physics section of the particles system. Its name is "subframes" and is set to 0 by default. Set it to 2, for instance. The principle is to calculate more simulation steps (here 2+1) during each rendering frame. To say it differently, for each frame (image) calculated, the simulation calculates more than 1 (here 2+1) frames so that it will not miss the collision (or will miss less)

You can also change the calculation mode : it is found in "integration". By default "Midpoint". But the tooltip says that "verlet" for instance is more accurate.

I think you are pretty skilled at this .... thanks a lot :)

Seriously, I am not... but I learn a lot with the questions : )

The most possible reason for that behaviour is non-manifold geometry.
When closing particles within the lamp by filling a face inside of the lamp, you create non-manifold mesh which might be hard to deal with for engine. Particles fly through from the bottom, where the face is created and which should block them.
To make the mesh as manifold one, first delete that inside face. Then you'll need to:

Solidify the mesh (either with Solidify modifier or by extruding geometry in Edit mode and scaling extrusion a bit inside).

Create a face which will block particles. For that, select edge loop, left from original face, bevel it with Ctrl+B and fill 2 new faces (they will be Ngons, however it doesn't really matter here).
Beveled edge loop:

Filling new faces:

Particles will  fly inside and collide with walls as expected:

WOW, Mr Zak. That is really a big improvement


text:
Blender: on/off collision modifier
I have a collision object with the fluid particle emitter inside. The idea is that when the fluid fills up the object, it explodes and all the particles falls out.
The problem is that I can't find a way on how to animate the collision itself and turn off the modifier on certain frame?

Typically you can animate any value in blender by hitting i. If there isn't an on/off switch, you can modify the collision object's geometry.
Go to the frame before the shattering. There hit i > Scale. Go to the next frame and sto scale the object up. Make it so big that it doesn't block the flow of the fluid. i > Scale again to save the size.
Now it should work.


text:
Blender Can't detect 3D hardware accelerated Driver
I have just installed blender 2.77a from blender.org om windows 8.1.
When i try to open blender it gives me an error as follows

Blender - Can't detect 3d hardware accelerated drivers.

I have checked my graphics card driver via windows update and it says my drivers are up to date. My graphics driver details are as follows (dxdiag) :

---------------
Display Devices
---------------
          Card name: Mobile Intel(R) 4 Series Express Chipset Family (Microsoft Corporation - WDDM 1.1)
       Manufacturer: Intel Corporation
          Chip type: Mobile Intel(R) 4 Series Express Chipset Family
           DAC type: Internal
        Device Type: Full Device
         Device Key: Enum\PCI\VEN_8086&DEV_2A42&SUBSYS_02631028&REV_07
     Display Memory: 1065 MB
   Dedicated Memory: 64 MB
      Shared Memory: 1001 MB
       Current Mode: 1280 x 800 (32 bit) (60Hz)
       Monitor Name: Generic PnP Monitor
      Monitor Model: unknown
         Monitor Id: LPL0000
        Native Mode: 1280 x 800(p) (59.976Hz)
        Output Type: Internal
        Driver Name: igdumd64.dll,igd10umd64.dll,igdumd32,igd10umd32
Driver File Version: 8.15.0010.2702 (English)
     Driver Version: 8.15.10.2702
        DDI Version: 10
     Feature Levels: 10.0,9.1
       Driver Model: WDDM 1.1
Graphics Preemption: DMA
 Compute Preemption: DMA
           Miracast: Not Supported
Hybrid Graphics GPU: Not Applicable
     Power P-states: Not Applicable
  Driver Attributes: Final Retail
   Driver Date/Size: 3/11/2013 15:49:02, 6593816 bytes
        WHQL Logo'd: Yes
D3D9 Overlay: Supported
            DXVA-HD: Supported
       DDraw Status: Enabled
         D3D Status: Enabled
         AGP Status: Enabled

Please tell me how i can solve this problem.

Same problem here with the driver error. Downloaded direct from website suggested above. Didn't work - still exact same error. Did OP ever get the problem solved? Thanks.

You should get "software" OpenGL:

Go to this link: http://download.blender.org/ftp/sergey/softwaregl/
Pick your OS version (86/64).
Put the opengl32.dll file into your top Blender installation folder (C:\Program Files\Blender Foundation\Blender). This should be the same location as your blender.exe file.

Blender should start.

i did this and it just crash. nice job sir.

This worked for me.

I installed the file from Blender http://download.blender.org/ftp/sergey/softwaregl/win64/opengl32.dll into C:\Program Files\Blender Foundation\Blender on a virtual Machine. Since now it is able to run without exception "No graphic card found". Now with success.

This worked for me

This Works for me

Blender uses OpenGL for just about anything (except rendering the final result) – Direct3D is no use to it, because Blender is cross plattform and Direct3D exists only in Windows. Hence you require a working, fully supported OpenGL implementation installed on your system. Microsoft years ago decided to actively sabotage OpenGL by stripping everything that is OpenGL from the GPU drivers that are installed through Windows Update and just leave around a software fallback for OpenGL-1.1 (totally outdated version from 1996).
The only way to get proper OpenGL support on Windows is to install the graphics drivers directly from the GPU vendor, i.e. the driver packages you can download directly from Intel, AMD, NVidia and so on. In your case you need the original Intel drivers installed.

i tried that too. But when i try to install drivers downloaded from dell the installer says : This computer does not meet the minimum requirements for installing the software.

so i don't know how to run away from Microsoft's drivers.

@RanaAliRaza: Dell does not make GPUs. Intel made your GPU. You want to download from here: https://downloadcenter.intel.com/download/26078/Intel-Graphics-Driver-for-Windows-10-and-Windows-7-8-1-15-40-?product=80939

Is downloading the drivers with geforce experience direct enough? I downloaded and installed my nvidia drivers multiple times with geforce experience and I still get the same error.

Both answers are valid with possible requirement of updating chipset code drivers and the loading opengl32.dll into the blender folder. Make sure its in the Programs folder or programs(86) depending on location 64 bit or 32 bit Blender folder respectively. Some of the newer computers or my engineering computer did not require the updated chipset drivers and Linux version didnt need drivers at all.


text:
User Persp implementation
Is the User Persp implemented as an invisible camera ?
When I rotate the User Persp with middle mouse button, does the entire world rotate or just this camera ?

It's not a camera you're looking through. The MMB rotates the view around a defined point in the 3D viewer.

As far as I understand it, a virtual camera is implemented in Blender. Blender users a GL library which implements it in some other way underneath though.
Could you tell what you are trying to achieve with this?
Edit:
(This is what I have gleaned by reading some of the source. If someone more versed into it can correct me, he or she should feel free to.)
If you dig into blender/editors/space_view3d/, you can find the actual implementation. In summary RegionView3D objects hold the reference to the area's perspective (and by extension what you refer to as a virtual camera) in the persp member variable. The reference to the physical camera object is held by View3D objects. These may or may not be the same. (Or rather the persp derived from View3D.camera may or may not be the same as RegionView3D.persp.)
Here is the view3d_setobjectascamera_exec function's code. It manipulates both cameras. I am on a phone right now, and I can only post a screenshot. It is from the 2.6 branch found on launchpad.

Only understand some implementation details


text:
How do I prevent rigid body objects from falling down before they are hit?
I have done BlenderGuru's Quick Rigid Body Fun on Rigid Body Collisions.

Regarding this .blend file:

When you play the animation, the cubes start falling down long before they are hit by the wrecking ball. This is because of gravity and because there is some space between the cubes. How can you prevent the cubes falling down or at least arrange that the cubes don't fall down before they are hit by the wrecking ball?
P.S Blender Guru says it is necessary to have some space between the cubes because if there is no space the wall will explode. I have here another .blend file...

...where there is no space between the cubes, so I don't think he is right. But the stones don't behave like there is a wall .... hmmmm ???

See http://blender.stackexchange.com/questions/2620/insert-properties-keyframe-for-multiple-objects

You need to reset the origin points of the cubes after you separate them from the arrays they were part of. They fall because the origin point is at the same place for all of them once you separate them. he explains to use Ctrl-Alt-Shift-C > Geometry to Origin, but when I do it, the cubes all end up at the same location, so I don't know what's up with that.

The reason I couldn't change the origin points was because I had rigid body physics turned on. I had to turn it off for the cubes first.

Now my physics isn't working at all.

The simplest answer to this is to apply transforms to all of the cubes. Ctrl+A>Scale and then in the physics panel, enable deactivation and start deactivated for all cubes so that the simulation does not take over the objects until they interact. Just enable the option for one, then choose copy from active in the Tool shelf with all cubes selected.

It seems to work and a indeed a simple solution. Thanks

I started with the first linked .blend file. After my short, 14-step method, I achieved this:

Make sure all the cubes and the cubes only are selected. The active object must be a cube.
Go to frame 85.
Go to the Properties panel > Physics tab > Rigid Body dropdown and uncheck the Dynamic checkbox.
Hover over the Dynamic checkbox and key I to insert a keyframe. It should turn from grey to yellow.
Key RightArrow to move to frame 86.
Go to the Properties panel > Physics tab > Rigid Body dropdown and check the Dynamic checkbox.
Hover over the Dynamic checkbox and key I to insert a keyframe. It should turn from green to yellow.
Key Shift + LeftArrow to go back to frame 1. Any simulated physics should have gone away.
Key Ctrl + J to join all of the cubes.
Tab into Edit Mode.
Key P to open the Separate menu and either key 3 or manually select By Loose Parts. All of the cubes should now have the aforeinserted (heh) keyframes.
Tab out of Edit Mode.
Select all cubes, if they are not already selected.
Key Shift + Ctrl + Alt + C to open the Origin menu and select Origin to Geometry.

Here is the finished .blend file that produced the .gif at the beginning:

This is more like a workaround than a real solution. As animation data is handled with, the only thing left is to link it. Already given solution - http://blender.stackexchange.com/questions/2620/insert-properties-keyframe-for-multiple-objects

@ShadyPuck do not really understand your comments, or did I miss something ?

@OldMan Lemon was here earlier, and we were discussing the fact that I forgot to write up steps 12-14. Lemon is someone who prefers to delete their comments after posting. If my answer helped, please consider marking it as accepted.

@ShadyPuck so your solution is essentially to work with keyframes and exclude the cubes from the animation till they get hit by using keyframes and the Dynamic check box ? The part that I don't understand is al joining, separating of the cubes (step 10 -14). I mean I already did separate the cubes and did set the origins, did not I ?

@OldMan The joining and separating copies the keyframes from one object to every object.

@ShadyPuck Although I prefer the Timaroberts answer I think it is good to know the solution you propose. So I would suggest to keep your answer. Thanks


text:
Cycles support for gtx 1070
I just got my MSI gtx 1070 gaming X card today and tried to render something in cycles but to my surprise I got this message.

Is Pascal still not supported? Are there anyways around this/fix it?
Any help is much appreciated

; ~ ; I thought they would by August, the forums have lied to me

Initial support for CUDA 8.0 cards has been added to master.
You can download a supported build of blender from the buildbot or any recent version.

From the developer meeting notes (Sunday 31 July 2016):

Everyone wants the GTX 1080 cards supported with Cycles, unfortunately the required CUDA 8.0 is still not official released. We can add their release candidate though. Sergey Sharybin and Brecht van Lommel check into this."

Proably applies to GTX 1070 too...

I just used the latest build (nightly builds?) and it works now, not sure if it's faster tho but it works :D


text:
Realistic Rusty Chain
I was doing this tutorial. I think the UV unwrapping in the tutorial is not done well. I think the UV map should look like this

But these top and bottom views show that I have done something wrong. Either in my UV unwrapping or in my node map.

The top view shows much more "rust" than the bottom view. This is why I think I have done something wrong with this "rust" image texture.
Here is my node map

How to make a realistic rusty chain link ? What should I do better ?

I don't think it's clear from the pictures what is wrong with those top and bottom pictures. Please edit your question with a description of what you think it is meant to look like and what specifically is wrong with those images.

You have two options: use seamless texture and unwrap chain to the edge of it for eliminate seams visibility. Second option (I always prefer) is make full procedural materials. Just use 3 noise textures - 1st in small size for iron detail bump, 2nd in small size for rusty detail bump. Now you create two different materials: iron and Rust. Use 3rd noise texture in bigger size for a mix this two materials. EDIT: in this case don't give sense use image texture, because noise texture give you very similar pattern. Only play with values.

@RayMairlot I edited the question and added a .blend file with the textures packed.

A seam is slightly visible around the chain link. This is due to the marked seams. You can retouch that with texture paint and a clone brush (strength set to 1). This method can also be useful to add rust where you want.

@Shubol3D I don't have any experience with procedural materials. I can try but maybe you can post your answer with a little more detail ?

@ Old Man : I'm really sorry, I'm busy now for make tutorial. But also I'm glad to help. I find this tutorial. https://www.youtube.com/watch?v=_8CmR_5KXFo    It is relative simple fundamentals
and can be amazing time saver.  No image texture = no seams, no unwraping and work for any object and can adapt to almost any shape. You only combine generated textures and use it for your benefit. I really recommend spend time and study this feature. You save this time many times in future :-)

@Shubol3D No problem, thanks a lot. I will try the procedural textures. Is is time that I learn that skill too

Seams are visible around the link at the lines corresponding to the UV seams :

To correct that, you can paint (texture paint) this part using the clone brush, preferably using a strength of 1 (if not you will have more blurry painting).
To clone paint, Ctrl+LMB at the position you want to clone, then paint along the seam :

Note that will change your texture. So make a copy of it before you do that.
For adding more rusty parts, you can use the same principle, both in order to have more rust at the places you want and also to correct the seams :

The same part, before and after (no need to be an artist to do that !):

Edit : to have more rust in a more easy way (but that will not correct the seam problem) you can move the UV map parts to the center. In this particular case, that will not have any impact for the other texture :

Thanks @lemon ...do you think there are some errors in my UV unwrapping and/or node map ? Why is the bottom view not very "rusty" ?

@OldMan, This is because the uv map parts seen from the bottom view are on the top and bottom of the rusty texture : these parts of the texture have much more alpha than the center (which itself corresponds to the top of your mesh). For the unwrapping this is ok I think. Probably you used Blender without touching it after that and that guaranty the best surface proportionality for the faces. A trick could be to mark the seams inside the link (and not outside) because this is generally less visible, like for the seams of clothes in the principle (but painting is necessary too).

@OldMan, concerning the nodes setup, something to try : having the rusty parts less glossy than the other parts.


text:
Macro operator children are not called from python
The Macro operator in the following code calls two other operators that log the calls of their invoke and execute functions. If the macro operator is called from the spacebar menu, the console output is what is expected:
TestOp1.invoke
TestOp1.execute
TestOp2.invoke
TestOp2.execute

However, if TestMacro is called from a python context (a script / addon / interpreter window), it returns {'FINISHED'} without calling the children operators TestOp1 and TestOp2.
What is the proper way to register a Macro operator ?
import bpy
from bpy.types import Macro, Operator
from bpy.utils import register_class, unregister_class

bl_info = {
    'name': "Test macros",
}

class TestOp1(Operator):
    bl_idname = 'wm.test_op1'
    bl_label = 'Test Op1'

    def execute(self, context):
        print('TestOp1.execute')
        return {'FINISHED'}

    def invoke(self, context, event):
        print('TestOp1.invoke')
        return self.execute(context)

class TestOp2(Operator):
    bl_idname = 'wm.test_op2'
    bl_label = 'Test Op2'

    def execute(self, context):
        print('TestOp2.execute\n')
        return {'FINISHED'}

    def invoke(self, context, event):
        print('TestOp2.invoke')
        return self.execute(context)

class TestMacro(Macro):
    bl_idname = 'wm.test_macro'
    bl_label = 'Test Macro'
    bl_options = {'REGISTER', 'UNDO'}

def register():
    register_class(TestOp1)
    register_class(TestOp2)
    register_class(TestMacro)

    TestMacro.define(TestOp1.bl_idname)
    TestMacro.define(TestOp2.bl_idname)

def unregister():
    unregister_class(TestOp1)
    unregister_class(TestOp2)
    unregister_class(TestMacro)

if __name__ == '__main__':
    register()

    # This doesnt call TestOp1 or TestOp2
    bpy.ops.wm.test_macro('INVOKE_DEFAULT')

The children operators need to be registered with their fully qualified internal name:
TestMacro.define('WM_OT_test_op1')
TestMacro.define('WM_OT_test_op2')

Good find...  TestMacro.define(bpy.ops.wm.test_op1.idname())

Doesn't work within the def register() function. At that point the Operators are not registered under bpy.ops yet:
`AttributeError: 'BPyOpsSubModOp' object has no attribute 'test_op1'`


text:
Something wrong with my hole
I am doing the Introduction to Camera Tracking in Blender tutorial by Blender Guru.

Somehow, I managed to mess something up, and supposedly hidden parts of the hole are showing. I don't understand where I went wrong. Thoughts?
Here is the .blend file:

Looks like the mask (the ground plane) is not big enough and therefore can't mask out the wall of the pit going down into the ground.

Your jagged ground plane isn't big enough. Use the following procedure to fix it.

Tab into Edit Mode.
Your outer ring should already be selected (it is in the .blend). If it is not, use Alt +  RMB to select the edge loop:

Key S to scale the edge loop up until you can't see the tube any more.

Tab out of Edit Mode.

btw ...your answer did do the trick, but I must say that I am not understanding what I am doing. Is this "jagged ground plane" a sort of mask ?

@OldMan Yes. The compositing makes it so. If my answer helped, please consider marking it as accepted.

You can also mix the material of the sides of the hole with a holdout shader while using the backfacing output of a geometry node as the fac input of the mix shader.
Without the holdout shader:

With the holdout shader:

The OP didn't help by tagging the post as Cycles, but the .blend is in BI.

If you download the .blend it is in cycles.


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

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

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

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

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

I think I understand your node set up and thanks a lot. Maybe there is one thing I don't understand and that is why you take the "generated coordinates" instead of the UV coordinates ?

@OldMan For whatever reason, UV coords didn't work right with the rest of the top nodes. I'm sorry that I can't give a better explanation.

Could you maybe edit your answer and include your comment. Maybe somebody else can shed some light on this and then we both have learned something :)


text:
How to apply textures with alpha channel?
I am doing the Introduction to Camera Tracking tutorial by Blender Guru and at some point he is applying a texture to create cracks in the road (around the hole, see image below).

As you can see there are no cracks visible in this image. I think the problem is that I don't know how to apply textures with an alpha channel ? But perhaps it has to with the node tree in the compositor. Blender Guru is working with Blender Render, I use Cycles.
Who can help ? Blend file with texture packed attached.
P.S I know there is also an issue with the floor but I think I can only ask one question

It looks like the ground that you are trying to apply the texture to is on the Background layer and is being used as a sort of a mask, so it is not being rendered.  What I did to fix your problem is duplicate the ground, move the duplicate in the Z direction just slightly to avoid it intersecting with your ground that is being used as a mask, and then move the duplicated ground onto the foreground layer, which you have defined as the first layer, by pressing M.

Now the ground will render.  Next, you need to apply the cracks as a texture to the new ground.  Applying textures with alpha channels is simple using cycles.  Here is the node setup that is used:

Now if you render your should be able to see the cracks.
\


text:
Animation Body Rig Mesh is Messed Up
So I was animating a scene for minecraft. The character rig was completely fine the entire time. Right when I got done animating I even previewed the animation and everything was fine and there was no problems. Then I added more to the animation and the character rig all of a sudden had a glitched mesh. I have no idea what is wrong with it, I believe that I might of accidentally parented it to something. So I tried to get rid of the character meshes parent if that was the case and the entire characters body disappeared. I have no idea what to do. Here is the image of what the glitched mesh looks like.

Looks like the weight painting got messed up.  Try adding (painting) those parts of the mess to the appropriate bones.

I tried and it didn't work

Is there a way to replace the mesh with a new one and reparent the mesh to the already animated bones?


text:
Background is not blending well
In the Introduction to Camera Tracking tutorial by Blender Guru, in the first 40 minutes, he gives an introduction to Camera Tracking and then shows how to make a hole in a road. He did this in Blender Render, but I'm trying to do this in Cycles. Somehow, I made a few mistakes because this is my rendered image.

Notice how there is a huge shadow where my mask is. Any thoughts on what I can do better?
Here is the .blend file:

It's your nodes for the plane. They are not optimized for Cycles. I'm writing up an answer now.

ohhh.... supers.

As I said in my comment, the problem is caused by your nodes for the plane. In BI, your plane rendered white with black cracks. In Cycles, you rendered black with white cracks, I believe. Also, your UV Mapping needed some touching up, as only part of the cracks image was actually showing. After fixing your nodes and the UV Mapping, I achieved the following result.

The following is the modified node setup for your plane mask. I used the Emission and Light Path > Is Camera Ray nodes to achieve the Shadeless effect provided in BI (logic from Import Images as Planes addon Cycles node setup). Then, I used the Alpha output of the cracks Image Texture to differentiate between white, normal, and cracks, black. I used the Alpha instead of the Color with Bright/Contrast to make a Fac: because in this case, there was a readily available B/W Fac: already.

Here is the .blend file. Note that I may have messed up several of your paths.

As an alternate solution, you can use the following compositing. Note the changes in the two nodes immediately following the mask's RenderLayer node. If you do this, do not utilize the above solution as well. I will say that this works slightly worse, but it's still reasonable.

I did post the problem with the cracks as a separate question http://blender.stackexchange.com/questions/60687/how-to-apply-textures-with-alpha-channel I will now study both answers and try to come to an understanding :) Thanks a lot

@OldMan Ok, I didn't see it. All I did was scale down the map until there were no cracks showing in the hole in the center. Then I just moved it around a bit to center the cracks better. Lastly, I rotated the map so that the cracks appeared facing towards the camera. I did all of this while in rendered view, so I could see my results.

no problem at all. I am very glad that you dive into this problem and learn me things :) Only reason that I mentioned that other question is that it might give you second thoughts.

maybe off-topic, but ... do you simply know an awful lot or do you have a gift to analyse new problems and come up with completely new answers (also for you) ? I am simply interested how you came up with this answer because this is really very unexpected answer for me (never heard of Light Paths)

your solution clearly works very well, but I have this "feeling" that to apply the texture with alpha channel like showed in http://blender.stackexchange.com/questions/60687/how-to-apply-textures-with-alpha-channel (but without duplicating the circle object) should also work somehow ... but I cannot get it figured out

@OldMan I'm not sure I have a gift, but I was never taught Blender; everything I learned I learned from Google, so I have a lot of practice asking the right questions. Plus, I have a good memory, so things stick.

@OldMan I didn't duplicate the mask, so I must have done something right. I did do this tutorial myself long ago (all in BI, though) but I believe my method, since it both shows the cracks and eliminates the weird shadows, should render the other one that you linked to obsolete. If you use my .blend file in the above post, you should not need the answer from the other post.

As I said, your answer works and is very clear (even I understand it haha). So yes I accept your answer happily. I also think I should learn to aks the right (at least better) questions

@OldMan Just added an alternate solution. It works slightly worse, but it's also simpler.


text:
Is there a way to create a seamless image in the compositor?
Can a rendered frame be made seamless, by some compositor tricks? What I'm looking for is something similar to the GIMP filter Make seamless.
Here's an example
Original (downloaded from Pixabay):

After Make seamless applied:

I could, of course, do this in GIMP, but I'd like to avoid post processing in external applications, and get a ready made image directly out of Blender. My goal is to have a repeating background and composite non-repeating text on top of it, and I'd like to be able to do it with two render layers or, if necessary, two scenes in the same .blend.
When searching Blender.SE, I found several questions about seamless images, but they all seemed to want to know how to use pre-existing seamless images, or how to get a texture to repeat seamlessly on an object. The ones I actually opened, did not answer my question, since I'm aiming to create a seamless image from a render.

I don't think it's possible, long time ago there was a thread (probably at blenderartist) to create 'seamles node' but I think it's dead by now. There is nothing wrong with using external apps to post process your work. I'm myself such a purist as you, and I wanted to make whole lightsaber in render even without compositing (!!!) but sometimes we need to give it up and use simple, outside methods.

@LukeD I know there's no node that does it directly, but I was hoping it could be done with some tricks with the existing nodes. I actually do post processing externally, but mostly pretty simple stuff from the command line, using ImageMagick. The problem is that GIMP still doesn't do 16 bit colour channels properly, and ImageMagick doesn't have a Make seamless filter.

So as far as I know the only 'trick' would be making masks and do it manually but that's pointless. I'm photshop user but I see that development gimp version (2.9.x) can do 16bit.

The question depends on the nature of the source image. In the Fireworks example the edge is already seamless (black). So you can use the compositor. Otherwise you would prepare the edges as the other answer suggests with a blending mask.

Import image
Add a Translate node, turn on "Wrap Both Axes"
Alter X and Y offset
You can add the original image back over the top with an "Add" mix
node.

I would mention that this method works only in the cases where the background is completely black, otherwise the "add" mix node would not be able to produce clean results.

Yes this solution is image dependent but I did write that in the response. with the Translate Wrap function I think you could go some way to making a general purpose group node for this effect.

Thanks. This is the one that lead me in the right direction, and my own answer has issues, so I decided to accept yours.

First of all, you need an alpha mask. It should look a bit like this:

Basically, black in the middle and white at the edges.
It should preferrably be the same size as the image you want to make seamless, but it also works if it isn't.
Make sure that you set the render resolution to the same resolution as the image you want to make seamless.
Go to the node editor, go to the compositing tree and add two image nodes, one with the image you want to make seamless and one with the alpha mask. Connect the image node with the alpha mask to a Scale node, and set it to stretch to the Render Size.

Add four Translate nodes and four Mix nodes. Connect the Image output of the image node with the image you want to make seamless to the Image input of each of the four Translate nodes. Set the X value of the first Translate node to 0.5, the X value of the second to -0.5, the Y value of the third to 0.5 and the Y value of the fourth to -0.5. Mix each of the Translate node's Image outputs with the original image using the Mix nodes, while using the alpha mask as the Fac input for the Mix nodes.

If you render it, the result will be a (somewhat) seamless image.

Note that there are still borders, this time caused by the borders in the alpha mask. You may want to experiment with different alpha masks in order to find one that works well for your particular image. For example, mine has a large black square in the middle, while you might be better off with one that has no square in the middle at all.
Here is the .blend file:

Even though this solution works, you are probably far better off using a different program than blender.

Thank you. I just had a quick look, and like you said yourself, I'll probably achieve better results with external post processing. But this is a good starting point. I will play with it, and see if I can improve it. I upvoted, but I'll wait a few days or so before accepting, to see if something ever better shows up.

Doesn't look seamless to me. Seamless at the edges, but now there are seams in the middle of the image. (actually at the edge of the black part of the alpha mask)

Indeed, my method is far from perfect, but using a different alpha map might help. In the end, the best way to make it seamless depends heavilly on the image. For example, it is possible to make the black background of the image in the question transparent, making it much easier to make the image seamless.

Combining the two previous answers, I came up with this.
Here is the original image, which I'm going to try to make seamless.

Add an Ellipse Mask node and connect its output to the Image input socket of a Blur node. Connect the output to the Fac of a ColorRamp node. Connect the rendered image to the Image input socket of a Set Alpha node and the Image output socket of the ColorRamp node to the Alpha socket of the Set Alpha node.
The Blur node blurs the edges of the Ellipse Mask, and combined with the ColorRamp the shape of the mask can be set quite precisely. The output from the Set Alpha will look something like this.

Connect the output of the Set Alpha node to a Translate node and enable Wrap: Both Axes.
After translating, the alpha channel will be something like this.

And the translated image, with the alpha channel above will look like this.

Connect the output of the Translate node to the lower Image input socket of an Alpha Over node, and the unmodified rendered image to the upper Image input socket of that Alpha Over node. Enable Convert Premul on the Alpha Over.
And this step combines the original image and the masked, translated one into this.

That's about it. Now just tweak the size of the Ellipse Mask, the settings for the Blur node and the positions of the handles in the ColorRamp node, and possibly the position of the Ellipse Mask and the values for the Translate node.
The image I used here isn't the same as in my question. I used this one to make sure I had one where the colours of opposite edges aren't identical.
Screenshot of the node setup.

After some further playing with this, I must confess that this has some issues with the masking. It can probably be solved by some tweaking, and I'll be looking into it as soon as I can get the peace and quiet.


text:
My mesh is not moving like the motion tracked video
With lots of help of you I ended up with this movie. Something has gone wrong because my mesh is moving .... Any ideas what has gone wrong ?

@cegaton Sorry, I will do better again next time. If you feel I don't improve, please let me know

Your solve error is too high:

You should aim for a tracking error of 0.3 (a third of a pixel)
Revisit your tracking marks and make sure they are not sliding. If they are re-track or try a different tracking mode.
Read: How can I get better results when doing camera motion tracking?

hmmm ... Blender Guru said that any value between 1 and 3 is good and values below 1 are very good. So it had to be below 1 ? Because I stopped  since I had a value close to 1