MrPrim and hanging/slow renders

[toddd]

Hi Everyone,


I am doing some R&D at work for a project we are working on, and have noticed that when I use hair and fur, along with the MrPrim setting that I am getting some slow rendertimes, and in some cases renders that seem to be frozen(on more than 1 workstation). So my question is, is there an efficient way to use mrprim with vray? I realize this may be caused by the temp file hair and fur uses, but want to know if this is a viable combo to use for a print ad I eventually have to render. I have tried using the vray and standard frame buffer, and tried using vray lights as well as standards lights with vray shadows.



Thanks for any help/info


Todd

[vlado]

Have you tried increasing the dynamic memory limit in the V-Ray system rollout?

Best regards,
Vlado

[toddd]

I'll give it a try Monday. Is there an amount I should use based on ram or anything like that?

[Morne]

if you are already on VRay 2.0 then just set it to 0. This will let vray use maximum available ram

[vlado]

if you are already on VRay 2.0 then just set it to 0. This will let vray use maximum available ram

A small correction - setting this to zero will remove the limit on the amount of RAM for dynamic geometry. That means that if the physical memory is overflowed, Windows might start swapping to disk, which will drastically reduce performance.

Best regards,
Vlado

[toddd]

So I am back at hair R&D today. I tried raising the dynamic memory limit to 2400(a random number as I wasn't sure what value to put). Still having the same issues. I have 16 gb of ram on the workstation I am using. any other suggestions?


Thanks!

Todd

[vlado]

I will need a scene to be able to tell you more...

Best regards,
Vlado

[toddd]

Unfortunately can't give the scene, but I just did a test with a simple sphere, generate some hair, added a target spotlight with vray shadows then rendered with each of the options. Buffer was very quick, geometry not as quick, and mrprim still very slow. I am running 3ds as admin.

[vlado]

By default the "Tip fade" option is enabled when you use the "mr prim" mode, which slows down the rendering a lot - every hair is transparent, whereas if you render in geometry mode, transparency is ignored. Turning it off speeds up the "mr prim" mode quite a bit. Geometry is probably always going to be the fastest option, but also the most memory consuming. In future builds, rendering of hair is somewhat optimized bringing it very close to the speed level of regular geometry.

Best regards,
Vlado

[LarsSonparsson]

Somehow, with Vray 2.0 sp1, the mrprim isn't working anymore. It doesn't generate any hairs. Geometry mode is the only way to go.

testing now with: Max 2009 x64 - Vray 2.0 sp1