Vray for Grasshopper - export vrscene

[aaouviz]

Hi all,

Long time, no see. I've been out of the game for many years now. I suddenly find myself testing out 30 days evaluation of all the latest software, so exciting December holiday coming up!

I have a Grasshopper issue. I'm trying to export animated geometry (using vray timeline) to a *.vrscene to then use in 3dsMax. It exports and imports, but the animation does not work. Any idea why?

(When I try to export as vrmesh, it processes, then crashes both GH and Rhino.)

If my screenshot and explanation isn't enough I've created a video to explain my predicament, but will only upload if there isn't an easy solution...

Thanks for any tips!

[nikolay.bakalov]

Hi, aaouviz

if not a problem, could you attach the GH definition (and the rhp if needed) here for investigation. If there are sensitive copyrighted work, could you attach as simpler as possible file(s) that stll reproduce the problem. Mind that any texture files and/or actiual materials are not required

thank you

[aaouviz]

Hi, thanks for your response!

I have attached the GH script, it has a simple box geometry imbedded in the script (which is animated over 100 vray4gh frames). My problem should be easily replicated.

However, I now think perhaps I'm generally missing something... I can't get vrscenes of any origin to animate... Am I wrong in presuming that vrscene should be animated (when applicable)?

Cheers,

[nikolay.bakalov]

Hi aaouviz,

the problem you're experiencing is called "alternating face ids limitation". That basically means that a proxy cannot handle certain morphing geometry. Your definition have morphing geometry since for each frame the BRep is meshed independently. For some frames we receive one face count, and for other frames we get another face count. This is due to the fact that the RhinoCommon mesher takes the BRep as is in the global coordinate system and meshes it. It doesn't see that you just rotate the same BRep. So for frame 1 we get 40 vertices, for frame 4 we get 58, etc...
This is not supported very well in the vrmesh infrastructure.

Now the real problem - since we're aware of that fact we check for alternations of the face ids between two frames. The real bug was that this check was somewhat skipped for the Exporter component in particular.

Fortunately there is a simple workaround. Just mesh BRep before transforming it. This is guaranteed to be deterministic, since the mesher is only invoked once.


I'm also attaching the modified file.

Thanks for the report. Good catch !

[aaouviz]

Excellent! Ah, so simple, I think I did try this at one point, but something got confused along the way and didn't work.

1 problem however still - When I export from GH and import in 3DS MAX, the animation works perfectly, as expected, ONLY when I export as *.vrmesh. If I export as *.vrscene the animation still fails to run (or is this expected? Sorry, I don't have much experience with VR scenes)

Thanks for your help - this is a big thing for me, I think Vray for GH is a massive deal