Linear EXR Texture Baking

Texture Baking 3dsmax/Vray -> Unity3d)

I wanted to post this up for future reference. Somehow I've managed to bake textures as .tga all this time without complaining - The problem is I wanted to try baking my textures as .exr. But when baking more than one object, you aren't able to adjust the filetype you want to export your baked textures as. So they default to .tga

While chatting with a friend about making a baking script for me, we stumbled across this post online - http://forums.cgarchitect.com/34620-render-texture-multiple-objects-jpg.html. Michiel Quist posts the steps needed to change the default filetype used by the Render to Texture dialog.

  • Find your 3dsmax folder and go into this subfolder ...\UI\MacroScripts
  • Edit 'Macro_BakeTextures.mcr' in a text editing program
  • Find this line, local    defaultFileType = ".tga" -- default bitmap file extension

I replaced .tga with .exr to try and take advantage of rendering textures in linear color space. I know Unity3d has buttons for working with linear color space.

So far in Unity3d I've done this --

  • Change the imported texture settings to 'advanced' texture type
    - Bypass sRGB Sampling, tick On
    - Encode as RGBM, tick Off
    - Generate Mip Maps, tick Off
    - Wrap Mode, Clamp
    - Format, Automatic Truecolor
  • Camera has HDR ticked. edit: this is been problematic. One thing is that HDR cameras do not support MSAA. Another problem is that Unity does not support post corrections to linear exr textures. You'd need to invest in Amplify Textures 2 if you wanted full control. But even then, the sacrifice of MSAA doesn't seem to be worth it at the moment.

  • Batch convert materials to lit/texture, then selectively go around and switch various textures/shaders to standard material to give reflective properties
  • Extra camera screen space adjustments

I'll try and put together a personal 3d scene at home that I can share this new process.

Workflow Exploration; 3dsmax to Unity3d

I haven't posted in a bit, since everything is still a mess. I've also been doing experiments with projects I can't share so that's another reason. But I thought I'd catch up on what I've been trying out so far. What has or hasn't worked.

So I'm currently trying to devise a workflow that allows me to bring scenes from 3dsmax, with all the glorious lighting from V-Ray baked into them.

Here's the current method:

1. Optimize all geometry as much as possible. Reducing turbosmooths, reducing curve interpolation on rendered splines and/or sweeps. Some things I've just applied an optimize modifier to reduce.

2. Unwrap. I usually do a shoddy job of just putting simple box mapping on objects. So before I start combining meshes, I unwrap them as properly as possible. I'm still trying to find a better workflow that doesn't damage the existing mapping until after baking.

3. Combine. At this point I combine the whole entire scene into a single object. This is simply so that I can explode it back into pieces based on material. This is because if I have two of the same material in the scene and bake them as two textures - the material is confused as to which baked texture to use.

http://www.scriptspot.com/3ds-max/scripts/detach-by-material-id
detach by material name

4. Organize. Now each mesh should have a jumble of UVs, so it needs to be packed more cleanly. Currently I'm simply using the 3dsmax pack uv function, but I'm looking into other plugins to do this better.

5. Bake! Everything should be ready to go. A couple important things are that; you make sure you're using regular cameras to preview the lighting. You can still use a vray exposure control to match an exposure so that it works with Render To Texture. Also make sure you're baking your gamma into the render. For me this is simply changing my color mapping mode to 'color mapping & gamma'.  Also I have the baked texture replace the existing diffuse slot texture, so that I can convert the material to standard and export with the geometry without issue.

In the Render to Texture panel, check 'color mapping' & select the desired elements to bake:

VrayCompleteMap - everything
VrayDiffuseFilterMap - just diffuse
VrayRawLightingMap - just lighting/shadows
VrayMtlReflectHighlightGlossinessBake - just the texture used in the reflection
VrayBumpNormalsMap - normals from bump material (if any)

I've gotten a lot of issues during this step - ranging from issues if any of the materials are anything besides a regular VRayMtl. So blend materials, 2-sided, light material will cause issue, the issue being that render to texture can't find the diffuse slot of that material to place the baked texture into.

6. Export. Once everything has baked. If you've set the baked materials to load into the diffuse slots. Next you'll convert all the materials to standard. I use this:

http://www.scriptspot.com/3ds-max/scripts/vray-material-to-standard-material

At this point I also use a script to load the diffuse textures into the viewport so they're visible. I can't find the exact script but there are multiple ones on scriptspot.

Now you can export everything as an FBX, I embed media, and for units scale I uncheck automatic and set it to centimeters.

7. Import. The FBX should load automatically if you exported it into your Assets folder somewhere. The model should also have all the baked textures on all its materials. You can now go through them and change them to more complex materials and load the other baked materials if needed (bump & reflection). I'm still struggling to find the best methods for reflections since all my materials usually have some sort of subtle reflective property w/ fresnel. I'll probably wait for Unity 5 before I purchase anymore assets - but I have been eyeing something like Candela SSRR or Screen Space Reflections (SSR). I still need to figure out and make use of the Shader Forge asset I purchased :)


I'll leave you with this, a little test I did yesterday. There's this triangle shaped building near where I live that has had the lower level up for lease, I've been wanting to imagine some use for this space. So yesterday I went and took about 150 pictures of the facade from all angles and processed them in PhotoScan - I got a pretty decent mesh that I'll use for reference when i model it properly. But for now I did a ProOptimize on it, and threw it into Unity to view :)