face count limit for Vray...

[davehitt]

Hello --

We've just finished a phase of a project where we continually experienced crashes rendering scenes with large amounts of SpeedTrees. I was told that Vray has, essentially, a maximum face count limit. I was wondering if anybody knows if that limit is definable, or if it is totally dependent on machine resources? Our machines are all running 2 gigs of RAM... Anecdotally, that limit seems to be somewhere between 2.5 and 3 million faces for us...

dave hitt

[dbuchhofer]

I've rendered scenes in the 7-8 mil range easily and without much error (though much pain to work in if not handled right).. primarily through the use of NatFX tree's.. and thats before any of the displacements come in to play..

alternatively i've got a scene in the 3mil range that is fairly painful.. but so far i've been able to track down most errors to either materials or to a faulty mesh object. (Damn its entirely too easy to corrupt meshes.)

Are you talking of unique polygons? instancing can help a *lot* in areas like this..

[Biohazard]

There's definetely a memory limit for 3dsmax to access (respectively 1.85Gb under win2k (ws) and 2.85Gb with winXP (+ the /3GB option).

We are rendering huge scenes (over 3-4M) + displaced geometry and the amount of polys is not the issue here.

[jsr]

We had crashes with a 2-3 mill model where most of the faces were in only couple of objects. After we divided the faces into several objects, crashes dispareared.

In windows memory gets fragmented like hard drives. If you have huge amount of faces in single objects there might not be enough continuous memory block for that object and the program crashes if memory allocations are not handled corectly. So making objects smaller in face counts might prevent crashes. This was an explanation from one colleaque of mine.

We had crashes in both VRay and max scanline.

[egz]

This is what Vlado posted on the discreet webboard a few weeks ago:
http://support.discreet.com/webboard.../read?81927,18

On 9/1/2003 12:29:42 AM, Antti Lehtinen wrote:
>Vray crashes while renedering
>very large scene. My scene
>contains 2,3 million faces,
>300 objects and almost 700
>textures. I found out that
>little heavier scene would
>also cause crash with
>scanline(application has run
>out of memory...). The crash
>happens every time when
>rendering. MAX just crashes
>without any error message. If
>I reduce(remove some objects)
>the scene a little(maybe
>500000 faces) it renders just
>fine. Any suggestions how I
>could render such a big scene
>with Vray?

Currently the amount of triangles VRay can render is limited by the available memory. A new dynamic system for loading objects on demand is on the way and will be available soon. In the meantime, you can try to reduce the memory used by 3dsmax by turning on bitmap paging (Customize -> Preferences -> Rendering, Bitmap pager settings).

Best regards,
Vlado

[davehitt]

geometry count

Wow, thanks for all the insights. We might have the "giant" object problem noted above. I collapsed a couple of huge buildings, resulting in large, single meshes. Interestingly, our problem was similar to one of the examples noted -- our scene rendered fine, until we exceeded a certain threshold. If we got rid of some trees, the scene was fine again...

thanks all

dave