FBX Export Freezing C4D

[VR Theatre]

I had problems exporting models to FBX a few versions back. Recent versions seemed to have fixed the problem, but I just got 2024.3.2, and the problem has returned! On export, the process hangs and c4d is frozen until it killed and restarted. The exported .fbx file is partially intact, but the materials are missing and/or misaligned, and objects may be oddly rotated.
Is there a setting or plugin that I can use to workaround this old/new problem?

[Dr. Sassi]

Hi VR Theatre,

I can't reproduce here any crash. Sorry. I checked all the information channels I have access to.

If you have a c4d that you can share here or as a Dropbox, Apple, Adobe, Google, or Wetransfer cloud-based file (no shortened URLS, please), I will check it.

Please contact tech support:
https://www.maxon.net/en/support-center

All the best

[VR Theatre]

I figured it out. In one material, the color channel had changed to Color+AO? (I don't know what that is.) FBX export couldn't handle it and choked halfway through. Thanks

[Dr. Sassi]

Thank you very much, VR Theatre.

Interesting find. Color and AO. AO stands for Ambient Occlusion, a technique used mainly in the '90s to produce some hints of how light behaves in "corners". Typically, it takes the geometry into account and has no light source. You can test that by significantly losing light to it and see if the result of the chosen render reacts to the light. Since it is a light-based effect that doesn't react to light sources, I think it is fair to say that it is fake. Valid in the '90s, where the only way to get GI for animations in reasonable render times was to bake a one-frame GI result into the mesh information. Which allowed for a static scene while the camera explored the space. But it was very "blurry" (if the mesh density was low), and AO gave it a bit of contrast to make it look better. I have explored that in over a hundred computer animation videos as a scientific project at the Technical University in Berlin. Perhaps the reason to be a little bit too picky with it.

When you have GI running in the scene, that "light trap" effect is already included, and wasting time on an AO pass seems not the best idea. But it gives a stronger contrast, and that might speak to some artists. If applied in Post as a pass, it is often applied via Blend-mode Multiply, which is the next problem, as it works there even more unnaturally. Everyone should do what feels right and what one likes to have their "style."

So, that leaves me with one question: if you place a cube into the scene and apply that specific material to it, the export will cause trouble. I would love to test that so I can write a report. Could you just copy the material in a scene and share the '.c4d' file here? Thank you.

All the best

[VR Theatre]

Try this zip file on GDrive
https://drive.google.com/file/d/1OwierBTZclkQ9bUHTBJa3GlYUqQxShz2/view?usp=sharing

Mark

[Dr. Sassi]

Hi Mark,

Thank you very much for the file and for using Google.

I can export it without a crash and import it without a crash.

The material export import is a different theme altogether.

I'm not aware that FBX has any handling on the Cinema 4D native Blend-Shader. Baking this before might be a good idea. At the same time, I get not tired of saying that AO is an outdated thing and should not be multiplied. If you must have that effect, typically already included in GI, use the AO as a mask for color adjustments. AO is a geometry effect, and no light source will change that. Hence, the effect looks fake. With the Color adjustment method, one can at least get the fill light's color established, typically during the day outside cold and in the evening or inside warmer. Or, like in a dense forest, it would be greener with all the thinkable varieties.

To my knowledge, no system on the market allows for a universal exchange of materials among all the DCCs and their options to convert materials to their native idea about it.

The best way is to ensure all textures and UV data are included and the receiving app provides its optimized material for the rendering if needed, manually set up. This is not a Cinema 4D limitation. The industry has been looking for a long time to establish a universal format. Perhaps we will get one—one day.

Enjoy your weekend