Very Slow material viewport preview management

[f2b]

Hi,

More and more the team is using the last Cinema 4D 2024 + VRay 6, and more we are figuring out that there is a big problem with material display in viewport / material preview in material manager.

Little scene runs fine, but big scene with 1500+ materials are horribly slow, there is a 2 or 3 seconds lag for each click each time we select an objet in viewport, or when draging the camera view... It's like Cinema 4D was accessing/checking each texture file on disk, for each material displayed in the current view. This routine is just a process killer and could explain the very laggy viewport with huge scene. And time to time another routine refresh material thumbnail preview, we don't know why... Another ressouce killer

I'm not sure it's VRay related, but i want to share this problem here, beacause i assume chaos team is best placed to relay this problem directly to the devs from Maxon department.

Best regards.

[deyan.hadzhiev]

Hey f2b, that is unfortunate to hear. But we would need a bit more details to troubleshoot this problem. Can you give us answers on these questions:
1. Are you using mostly node materials or classic materials?
2. What is your preview quality in preferences? Is there difference if you lower the quality?
3. Is disabling material preview solving the problem?
4. What if objects are hidden from the viewport, like Solo mode? Is it still unresponsive?

Additionally, you may try to decrease the render resolution of textures. For classic materials this may be done globally by the option in the V-Ray preferences (1) and for node materials, you may change it from each materials' Viewport tab (2) (probably can be done by selecting all node materials):



A very simple calculation is that by using the Default map sizes (of 256KB per material) you would have almost 400MB of just textures to be stored on the GPU, and if Cinema 4D loads them on each update, it can easily explain such slow downs.

And last but not least - can you try opening the scene in Cinema 4D 2025 and also opening the new Object profiler dialog - it may show what is troublesome in your viewport rendering. It is easiest to open it from the commander dialog (Shift-C):