Cinema 4D 2026.2 / V-Ray UI Bug after Rendering (Save dialogs not opening)

V-Ray for Cinema 4D V-Ray for Cinema 4D :: Issues
1

Hi,

I’m experiencing a strange UI issue in Cinema 4D 2026.2, Windows, last nightly vray version / CPU only:

After doing a preview render in the V-Ray Frame Buffer (VFB), the UI partially stops responding :

  • Menus like “File” open, but submenus like “Save As” do nothi ng

  • No dialog appears (seems blocked or offscre en)

  • After waiting, it sometimes recovers, otherwise only a restart h elps

SINCE:

  • The issue started right after updating the AMD chipset driver yesterday (don’t know if this rel ated)

  • I also tested rolling back the chipset driver today, but the issue still occurs

What I tested so far:

  • Preferences reset → temporarily fixes it

  • Removed plugins (including CV Toolbox) → n o change

  • Clean NVIDIA driver install

  • Tested different scenes → issue only happens with a speci fic scene

After isolating the problem, it seems related to a V-Ray node material using displacement channel and no geometry tag. Copying everything into a new file, without that material and rebuilding that material and using a geometry tag fixed the issue. Any Ideas, what happened?

2

Is it possible that some of the displacement materials in your scene have really high subdivision values i.e. really low edge length/high max subdivs? And as always a scene would be helpful.

3

Hi,
are you having a problem with the viewport? Are you able to save and then close the program? Can you change the viewport window, but it’s still unresponsive?

4

Hi, yes also problems with the view port. But as mentioned it is only with one special project.. Tried to reduce it, much as possible to send it, but reduced the problem is gone… I can’t share the full client project…