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Baking Texture Maps Clarification
Posted: 28 October 2021 07:11 PM   [ Ignore ]  
Total Posts:  42
Joined  2020-07-14

Hello all,


    So there are many, many tutorials and articles out there on baking texture maps. Most of them focus on different aspects of baking but not the general essentials. So, I’m having a little trouble understanding some fundamentals, especially as they relate to C4D. 

I could use a little clarification/confirmation on some key points:

1.)  Baking texture maps has several uses. 
   
    -High detail to low detail projection between models
    -exporting/creation of channel and texture maps created procedurally inside C4d
    -exporting specific attributes such as AO, Curvature, position for ‘smart’ shaders in programs like painter
    -creating texture maps with light information baked into them to save render time and calculation

2.)  Using the ‘Bake Object’ command in C4d is a variation of the ‘Bake Material’ command, but with a few less features,
    and can only bake data that is active in the material/shader/render globals.  e.g. Ambient occlusion, luminance

3.)  Baked textures with light information can replace their original textures, and lights can be turned off (not including GI/LUT)

4.)  GI can not be baked in C4D, you can only adjust the settings for better results (I see a lot of language about Baking GI
    online, but no explanations on how to actually do it)

5.)  I attempted to bake a texture using the projection effect under the diffuse shader and got very strange results.  Is texture
    baking optimized for UV referenced textures only?

I know it’s a lot of text but it is a product of LOTS of youtube and reading.  Just need clarification

thanks,

  Jerry

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Posted: 28 October 2021 07:58 PM   [ Ignore ]   [ # 1 ]  
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Hi Jerry,

There are certainly a lot of ideas about what works and whatnot. I have no general answer to your questions. Most of them, as usual, need to be seen case by case. I like to answer based on scene files, they work, or they don’t - no discussion needed.
Also, here, this is my take on it. That doesn’t mean other perspectives are questionable. Not at all. In a nutshell, what works wins.

First of all, material baking or light baking, etc., makes only sense if the information that will be baked in is not dependent on anything that changes.
Qualities that can be baked if the camera moves: Specular, Refections, GI to a certain degree as the viewing angle to a surface changes its qualities (Fresnel), and of course refraction.
If the object moves, additional limitations will occur, like subsurface scattering, lights, and shadows.
The theme of AO is a very old one. I think we have passed that idea to use fakes. With fast GI engines, we get better results since that is what they produce. To put it in twice (GI +AO) is questionable. On top of that, they are independent of any light source, just a fake, so that I would avoid them.

1
High detail to low detail. That is a question of how close the camera comes to an object. Typically at least 1.5 times the resolution of the final image should be the texture resolution. (Going by the object in the final render image, the texture itself has no other reference than that.)

Typically all influences to the surface, like with normal maps, should be 32bit/float/channel. Whereby a curvature map might get away quickly with a 16bit/channel. I exclude natural 8bit/channel in my answers. I think that format has nothing to search inside a proper pipeline, but people use it. Make your pick.

2
Baking anything with light information requires the baked texture, but one could also use a reprojected render (Camera Mapping). With faster render engines, we have less and less advantage of baking, considering the time investment initially and for every single change of the scene. Of course, there are uses of it.

3
Yes, and no, for obvious reasons in animation.

4
I would cache the GI results. Also, here sometimes camera mapping is faster, but view angle limitations will occur. GI can be baked in the Illumination part.
https://help.maxon.net/c4d/r25/en-us/Default.htm#html/TBAKETEXTURE-ID_BAKEOPTIONS.html#BAKETEXTURE_CHANNEL_ILLUMINATION

5
I’m not clear what you are referring to.

Those questions are best addressed with a tutorial request, with specific examples. Please feel free to do so in the Tutorial Request forum. THanks for considering.

All the best

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Dr. Sassi V. Sassmannshausen Ph.D.
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Posted: 28 October 2021 08:19 PM   [ Ignore ]   [ # 2 ]  
Total Posts:  42
Joined  2020-07-14

Thank you for your generous responses Dr!  I will have a dive into camera mapping, since that sounds like a very critical tool.  For my last question, I set up a PBR material with the physical renderer set up.  I had the normal map and reflectance boxes checked.  For the default diffuse layer under reflectance, I set up the projection affect for the diffuse shader.  I was trying to work around some troublesome UV’s and hoped I could bake out a texture map with that shader.  but the results were odd.  I’m attaching a photo reference of the settings.  I concluded that maybe the projection effect could not be baked, but I think maybe it was just my set up, since the point is to capture the texture as it appeared.  Still, I’ve gathered a lot from your response.  thank you very much indeed.

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Posted: 28 October 2021 08:30 PM   [ Ignore ]   [ # 3 ]  
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Thank you very much, Jerry.

As I wrote, scene files are the key. Images tell only a tiny part of the story, and I think they are more often than not misleading (thanks for the image and effort, but I want to help, and that is not a given with an image.)

YES: UV is the (one important) base for quality, and I haven’t seen a shortcut for that. Learn it once, use it often. There is no way around that theme. Sorry to sound like a boring mathematic-teacher here.

Cheers

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Dr. Sassi V. Sassmannshausen Ph.D.
Cinema 4D Mentor since 2004
Maxon Master Trainer, VES, DCS

Photography For C4D Artists: 200 Free Tutorials.
https://www.youtube.com/user/DrSassiLA/playlists

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