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ajz3d

A few questions from a new user. Mostly Paint Room and related stuff.

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Hello.

I've just purchased 3D Coat after my trail ended. I have to say I tried the hell out of it and I'm very impressed with the software. Sculpting with voxels is something I've been looking for for a long, long time, ever since I saw Ken Silverman's Voxlap engine. While not directly related to 3D modelling or sculpting, it showed how powerful voxels might be. I never quite understood why nobody picked up the idea of using voxels for volume shaping and model detailing. And then there was light - I've stumbled upon 3D Coat!

But enough of praising the app. I've been doing a hero character in 3D Coat lately and I'm a bit puzzled about the some aspects of the workflow. I would like to address a couple of questions to more experienced 3D Coat users.

  1. My character consists of several parts (body, tongue, a pair of tendons and two groups of teeth, each on a different VoxTree layer), so I'll be using several different materials after I import the retopologised model into Maya). I need those parts to stay on separate UV spaces and maintain proportions in relation to each other. I have already retopologised the volume and placed each part of the character on a different retopo layer. Unfortunately UVs from each one of them are bunched up together on a single UV space and I can't seem to find a way to separate them to different UV spaces. How do I do this?
  2. Does a voxel shader affect textures in Paint Room in any way, or is it completely ignored?
  3. There's a Layer 0 in the Paint Room. What does it contain? Looks like a geometry, but other layers (that were created with the Merge with NM command from Retopo Room) seem to contain geometry as well? Layer 0 can't be deleted.
  4. UV Room most of the time stays completely empty, even after I unwrap UVs in Retopo Room. It fills with content after I Merge with NM. Is it normal?

Paint Room has me completely puzzled. :wacko:

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1. I think you might just need to use the Unwrap command. It will unwrap all of your UVs along your seams and then efficiently pack them all into a single UV tile. If you want more than 1 UV tile, then create a new UV set at the upper left corner of the screen. Then select the UV islands you want in the UV preview window (they will highlight in blue), and then use the "Move selected faces to..." drop down in the upper left corner of the screen.

2. Yes, the voxel shader will affect textures in the Paint Room. For example, when you use a command like Merge with NM in the Retopo menu, you will see that the diffuse information from the material will be baked into a diffuse layer in the paint room, and the depth information from the material will be baked into a layer called Normalmap in the paint room.

3. As far as I can tell...Once you have a mesh merged into the Paint Room, then Layer 0 is similar to smooth shade view in Maya (like pressing "5" in the viewport). Once you turn on the layers above Layer 0, then that is like pressing "6" (show textures) in Maya.

About the Paint Room:

The Paint Room is only for painting your model. You can paint directly onto your voxel mesh or you can paint onto your retopo mesh after merging it into the Paint Room.

In order to paint on voxels you need to go to Preferences and in the General Tab turn on ShowBetaTools. Then go to View and select ShowVoxelsInPaintRoom.

Technical Note: When painting on the voxels, it will automatically switch your voxel objects to Surface Mode. Therefore it is not technically painting on the voxels, but rather is painting on a dense polygonal proxy mesh. If you then switch out of Surface mode back to Voxel mode, then all of your paint work will disappear. Don't worry it is not gone forever. Once you return to Surface Mode your paint work will reappear. Painting in this way is good because you can get high resolution painting results similar to Polypaint mode in Zbrush. You can then bake your voxel paint work onto your retopo mesh when merging into the Paint Room.

The layers in the Paint Room function very similar to layers in Photoshop. It helps to think of them in that way.

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Oops I forgot your number 4.

There won't be anything in the UV room unless you import a mesh (like an OBJ for example) into 3D-Coat. Then the UV room will show the UVs associated with your imported mesh. If you build a retopo mesh inside of 3D-Coat and make UVs inside the Retopo room, then those UVs won't show up in the UV room, but you can see them in the UV preview window.

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When you "Merge" anything from the Retopo Room into the Paint Room, your unwrapped UV mesh will appear in the UV Room - that's the way it works - and when you import an object into 3DC that has UV's - these will appear in the UV Room, as well.

Don't worry about Layer 0 in the Paint Room - it's just there.

To understand the Paint Room, it helps to understand the origins of 3DC as a texture painting program. It is much more economical to introduce medium to high resolution detail by means of textures than it is to model them in voxels or polygons. That is why there are so many "baking" functions in 3DC.

Once you have sculpted your model - to the point where very small details need to be added, as well as diffuse color and specular color - it's time to "Merge" your sculpted model into the Paint Room - where you can paint actual displacement, bump, color and specular, simultaneously, or one at a time.

Since 3DC is not an end, in itself, to the entire 3D creation process, it is designed to offer many export functions for use of your completed model, and its associated textures in other programs.

Greg Smith

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A few things worth noting:

Consider the Paint room and UV to be together, they really go hand in hand and maybe, should be grouped on the top bar as such. They function on the level that you would expect any other application to deal with meshes. You have mesh, you edit UVs, you paint details.

The Retopology room is more of a "meta" room, wherein your meshes are not live (in the paint/UV rooms) yet, until you send it to the paint room via the merge command. That retopology mesh has no bearing on the paint or UV room, which is why it has it's own UV tools (mirrored from the UV room).

The same could almost be said of the Voxel room, in that until you merge a mesh from this room to the paint room, the paint room has no effect on the voxel room. This has recently changed, in that you can now paint directly on something from the voxel room so long as it is in "surface" mode in the voxel room, you have the beta tools turned on in the preferences panel and lastly, from inside the Paint room, under View>ShowVoxelsInPaintRoom must be active.

On Layer 0, that is the mesh data. Don't ever delete it (in PS this can be done, definitely don't do it.) You'll lose much work otherwise.

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Guys, many thanks for your responses.

I've managed to organize the retopo'ed mesh into separate UV spaces thanks to the info you gave me and I'm beginning to familiarize myself with the Paint Room.

However, I've stumbled upon a small problem here...

If I have, say, two geometry pieces in the Retopo Room, both on different layers and UV spaces, then how do I toggle their visibility in the Paint Room, so I can paint under the tongue, for example?

There's the Objects tab in the lower right corner, but containing only one object (named something like: "head_tongue_teeth_.../etc/" - basically layer names from Retopo Room merged into one string) and not pieces from my retopo layer.

Ah, please ignore this this question. :)

The moment I stopped writing this post, I've noticed the Materials tab, right beside Objects, that contained all of my sub-objects. The name's a bit confusing as I thought it had something to do with the other Materials - those that you use to paint your model with.

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Hi!

Glad you got it figured out. :)

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An odd thing happened today. When I press Space in the Paint Room a very convenient circular Tool Palette appears:

20120627125027.jpg

But when I right-click the wheel and load custom palette, like a preset Skin colors.aco for example, the Tool Palette turns into this:

20120626183344.jpg

While it looks pretty interesting, it's completely unusable. I can select tools from the radial menu, but colours (within and outside of radial) are all unselectable. Is it some kind of a beta feature not yet fully implemented (I'm using CUDA x64 3.7.08B version of 3D Coat) or is this a bug?

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Also, a curiosity...

Those teeth below, have a Default shader applied to them and are painted with pure white colour. The lighting settings are 0 for ambient and 50 for primary light intensity. As you can see, they appear gray (@ ca. 128 RGB). The worst thing is that the exported diffuse colour map is also 50% grey instead of white! I've noticed, that when I hide Layer 0, everything displays as it should be in the first place and it exports correctly, meaning - painted whites are white in the texture map. I believe, that the Layer 0 is the shader layer, which affects all of paint layers and thus should be set to visible only if one intends to render with 3D Coat's internal renderer. Am I right?

20120627150242.th.png

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An odd thing happened today. When I press Space in the Paint Room a very convenient circular Tool Palette appears:

But when I right-click the wheel and load custom palette, like a preset Skin colors.aco for example, the Tool Palette turns into this:

While it looks pretty interesting, it's completely unusable. I can select tools from the radial menu, but colours (within and outside of radial) are all unselectable. Is it some kind of a beta feature not yet fully implemented (I'm using CUDA x64 3.7.08B version of 3D Coat) or is this a bug?

That's an old bug that I had a hard time reproducing. If you could please add your findings and content to the report Andrew may be able to fix this old nasty bug! Here is the report:

http://3d-coat.com/mantis/view.php?id=359

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Sure thing.

I've put some info there already. I dunno whether I said anything new or not, but perhaps it will help somehow.

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Awesome, thanks! Every bit helps that we can get. :)

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I have a question about workflow non-linearity.

Imagine you've already painted the texture, but your boss strolls in and decides one more thing needs to be added or changed in the voxel model. He wants ears to be larger and the character needs to have a long coat instead of a shirt or whatever. So, some volumes have to be altered in the Voxel Room and the model has to have its retopo mesh corrected afterwards. Is it possible to somehow preserve the texture information that one already have, or at least a part of it, so the changes done to the model wouldn't require one to start painting the texture from scratch, again?

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I have a question about workflow non-linearity.

Imagine you've already painted the texture, but your boss strolls in and decides one more thing needs to be added or changed in the voxel model. He wants ears to be larger and the character needs to have a long coat instead of a shirt or whatever. So, some volumes have to be altered in the Voxel Room and the model has to have its retopo mesh corrected afterwards. Is it possible to somehow preserve the texture information that one already have, or at least a part of it, so the changes done to the model wouldn't require one to start painting the texture from scratch, again?

Great question ajz3d! I too would love to hear a solid answer for this!

But...as far as I know, I think there is a workflow for this in 3D-Coat which involves using the texture baking tool. In the texture baking tool there are some options to select two different meshes (each with different topology) and then you can bake texture information from one to the other. I guess one of the meshes is your source mesh "input mesh" and the other is your target mesh. I've never done it before, and I don't know how well it works, but I'm guessing that is the correct path to take...

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Timmy, thanks for the info. I'll test this baking tool out as soon as I finish texturing my character. I wonder if it will do the trick.

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In the meantime, before experimenting with workflow non-linearity, I've been looking at 3b file sizes and I couldn't help but ask a question. Judging by the enormous weight of files that contain texture data from texture layers, created in the Paint Room, textures are all embedded in the 3b files. Is there any way of linking them to physical files instead, so they're not stored within the 3b? Like it's in Maya for example?

This would also enable to easily edit the textures with 2D application, like Photoshop, without the need of having 3D Coat running and increase the "security" of the texture files (in case of 3b becoming corrupted).

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Does Photoshop store layers externally? I don't think it does. In Maya, you aren't working with a layer structure, like you are in a texure/painting app. Maya is linking to a Texture Map, so it's somewhat of an Apples to Oranges Comparison.

If you merge down all your layers, then the file size won't be so big, but it's all relative to what you are asking 3D Coat to do. You want 4-8k maps and lots of layers (each one having 3 maps per layer...Diffuse/Depth/Spec)? Cool, but you're asking 3D Coat to store a ton of information when saving. Having said all of that, I have been thinking about asking Andrew to look into some sort of caching system artists can use when working with large texture maps.

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If you zip the 3dc files they become extremely small. Andrew once said he could compress the file format but at the expense of performance. I'd rather zip and archive old files than deal with constant lag in performance.

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Hm, I think we've got a slight misunderstanding here. Perhaps, because of English not being my first language, I did not express myself correctly. Let me explain.

First of all, I've never said that Photoshop stores its layers in external files.

Second of all, when I referred to Maya as an example, I meant that it links the textures from files instead of storing them in its native .ma or .mb files, unlike 3D Coat. You can tell Maya not to load texture files that exceed a certain resolution and manually load only the chosen ones. Nothing about layers here too.

Let's say you're painting (per pixel) a 4096 map on a model. Initially, you start with a normal map plus one layer (not including Layer 0). That's two 4096 textures. Let's say we're making textures for mental ray's misss_fast_skin shader. What you need is: diffuse colour, diffuse weight map, epidermal scatter colour, epidermal scatter weight, subdermal scatter colour, subdermal scatter weight, back scatter colour+weight, not to mention primary and secondary specular colour and weight. Each one of them having several sublayers for future flexibility, so you won't end up with your boss or client telling you to change something, and you having to repaint half of the model to achieve that. Like he'd like veins running under the skin to be darker and perhaps acne a little bit more oily. I'm referring to your suggestion about merging layers here. The more layers you have, the more flexible you are.

But... (how I understand it) each of those layers (like those several dots that stand for diffuse colour sublayer for acne, for example) is 4096! Wait a minute, this means we have bazillion of 4096 textures loaded into memory at the same time and the hard disk is working like crazy now, accessing the pagefile.sys. And if we work on reflectivity at the moment, we don't even need colour or subdermal layers in loaded into RAM at all.

This is why I think file linking is necessary. If each layer in Paint Room would be stored in a separate image file, you could completely unload unnecessary layers from memory. And what if you want to open the file to do something other than working with textures? Do you need to load all of that information? No.

Also, if you'd need to make this exemplary acne more oily, all you'd have to do, is to open acne specularity, acne reflect weight and perhaps acne diffuse weight texture files in Photoshop only, without the need of even launching 3D Coat!

I hope I've managed to clarify on the above example what I meant in my previous post.

Call me crazy, but that's how I think things should work when it comes to texturing. :)

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Also, a curiosity...

Those teeth below, have a Default shader applied to them and are painted with pure white colour. The lighting settings are 0 for ambient and 50 for primary light intensity. As you can see, they appear gray (@ ca. 128 RGB). The worst thing is that the exported diffuse colour map is also 50% grey instead of white! I've noticed, that when I hide Layer 0, everything displays as it should be in the first place and it exports correctly, meaning - painted whites are white in the texture map. I believe, that the Layer 0 is the shader layer, which affects all of paint layers and thus should be set to visible only if one intends to render with 3D Coat's internal renderer. Am I right?

20120627150242.th.png

Try to use this series of custom shaders from one of the default simple shaders that bakes predictably into specular and diffuse:

Baking Vox Layer shaders to textures

http://3d-coat.com/forum/index.php?showtopic=6863&st=0&p=51861entry51861

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