Render viewport subdivsion slow

[sharktacos]

It seems to me that the Vray implementation of subdivisions is quite slow.
If I alternately smooth the mesh, the render times speed up dramatically.
However, this is suboptimal, since I don't want to have a lot of heavy meshes in a scene, rather I would like to have it display as lowres, and render as a smoothed subD, and do that fast (which is of course the whole point of using SubD's).

Are there any work-arounds for this, I should be aware of?
Can we expect to see this improve in the near future?

[mr furious]

you need to turn on render viewport subdivisions and then tune the tesselation from the Settings tab .... by default it 4.0/256 which is quite high... make it 4.0 and 2 or 4

that should do the trick.

A

[aweidenhammer]

This is a pretty common thread, and has been posted numerous times, but you need to increase your dynamic memory limit (in settings). 500mb is too low for subdividing most geo at rendertime. set that low, it will only be able to subdivide portions, render it, then dump the memory and subdivide the next portion... very slow. I have 12gig ram, and set it to about 7000 for most scenes. Generally half of your ram should be fine, but for some scenes you may have to go higher.

that said, it is generally faster to pre-smooth your mesh at this point. Vlado has talked of making some changes there, but from what I know at this point, it's still better to pre-smooth if you can.

andrew

[sharktacos]

This is a pretty common thread, and has been posted numerous times

I thought it might be, but did not come up with anything after a quick search. Thanks for be patient with me asking a noob question, I appreciate it!

[vlado]

You need to increase the "dynamic memory limit" setting in the "System" tab of the V-Ray options. The default (400 MB) is typically too low. We are also working to obtain this value automatically instead of relying on the user to set it...

Best regards,
Vlado

[super gnu]

so that would be a dynamic dynamic memory limit then. this be a max feature too? a useful little addition i think.

[vlado]

Which feature? You can use render-time subdivision surfaces in 3ds Max as well (the "Subdivision" mode of the VRayDisplacementMod modifier).

Best regards,
Vlado

[sharktacos]

I changed it from 256 to 8 and now it is super fast again (yippie!)

Andrew, this might be a good thing to go over in one of your vray videos (which are awesome by the way!)
I wish it had been mentioned in the Nederhorst Primer too.
Both Subdivisions and displacements can really kill the render times, so it is an important thing to be aware of.

[super gnu]

i was referring to an automatic dynamic memory limit, not the subdivision system

[vlado]

i was referring to an automatic dynamic memory limit, not the subdivision system

Yes, of course; it will get there as well.

Best regards,
Vlado