render time

[luft]

Does V-ray's rendering time depend heavily on size and poly count in your scene as much as Radiosity does?

 

Some of my exterior scenes are quite big and wondered if it is practical to use.

[ecastillor]

one of vray´greatest virtues, is the ability to handle large and complex geometry....specially in exteriors....

 

It goes through it like butter!

[Christopher Nichols]

 

Some of my exterior scenes are quite big and wondered if it is practical to use.

 

Define big in your case?

 

There are many way to deal with "big" scenes. I have rendered 27 million unique polies with proxies, and I have rendered 1.8 billion with instanced geometry. Quality and sampling rates effect your rendertime more than polies.

[tecton3d]

I have rendered 27 million unique polies with proxies, and I have rendered 1.8 billion with instanced geometry. Quality and sampling rates effect your rendertime more than polies.

 

Wow ~ I've got poly envy! What kind of workstation does your crew use to get a file like that off the ground?

[AJLynn]

Get a 360,000 poly model and instance it 5,000 times, with Vray it's not nearly as bad as it sounds. Surprised me too. Some people were talking about it in a thread about mental ray on the 3rd party renderers forum so I tried it on my laptop - P4-2.4 with 1GB - and it performed reasonably well.

[Christopher Nichols]

Wow ~ I've got poly envy! What kind of workstation does your crew use to get a file like that off the ground?

 

I did the 1.8 billion poly model on a dual pentium 3 650. Only needed 256 megs of ram... Rendertime took 1 hour 22 mins. I tried it on my new laptop and it took 20 mins... that was at film res (2k).

 

[gfa2]

I have problems with big files and vray sometimes. I get memory errors. I've tried proxies...I've tried instancing. I also get errors when I try to render highres (3000 or 4000 pixels wide). Looking at Christophers picture above...I'm thinking, what am I doing wrong with my 1 million poly scene.

[Christopher Nichols]

You just have to be smart about it. You need to do things like VrayProxy, or switch to Dynamic Geometry:

 

http://www.spot3d.com/vray/help/VRayHelp150beta/render_params_system.htm

[gfa2]

cool...I've read about that dynamic geometry in the help file, but I've never tried it. I'll give a go.

[Jeffrey]

So is it mean what effecting the render time is mostly the lighting and materials?

[Christopher Nichols]

What effects the render time the most is how many rays are cast.... this effects glossy rays, indirect rays, how may bounces, how many samples and subdivs, anti-aliasing, etc... Geometry has a factor too, but not as much. I can make a rendering of a sphere super slow by cranking up the AA to an insane number.

[JamesTaylor]

You just have to be smart about it. You need to do things like VrayProxy, or switch to Dynamic Geometry:

 

http://www.spot3d.com/vray/help/VRayHelp150beta/render_params_system.htm

 

Chris,

 

i'm doing more renderings recently with 2d vray displacement but keep finding that after i've added a certain amount of objects with displacement that vray will crash during the calc phase of the irr. map or even before, during the scene setup stage

 

UNHANDLED EXCEPTION: Sampling displacement maps last marker is at.........is the error message,

 

i have been putting this down to the displacement requiring more RAM than i have available (2gb) and turning various elements off and on and rendering a no. of passes to make one final image. This is with the static geometry method.

 

Am i right in thinking (having read the link in your previous post) that if i use dynamic geometry it should solve this problem? rarther than trying to load all the data for displacement in the scene at once, it will just load the data required for each rendering bucket at any one time?

 

so If i follow so far, I presume if the maximum memory limit isn't sufficient for the data required by the one bucket i will have the same error occur as in static mode when the whole scene data is attempting to be loaded into memory.

 

Finally, if this is the case, wouldn't the best idea be to up the maximum memory limit to say 1.5gb or would this affect the render performance in another way?

 

Hope that makes sense! It good to have such knowledgable people around to help us all understand the finer details of issues!!

 

Thanks

 

James

 

BTW: you can definately recommend 3dpowerstore.de to us europeans for purchasing your DVD's arrived within a week......plus free pen!!! (i'll drop that in the original thread i started too)