Vray - complex scene render optimization

[denic]

I am currently working on my biggest exterior scene. It has 120 buildings with more than 450.000 square meters. I'm modeling complete detailed terrain with streets, cars, trees, grass, people... I already converted buildings and trees to vray proxys and also scattered grass... but scene takes long time to render.

I need to make 5 min. animation of building complex. So...

 

I would appreciate any possible idea to speed up things. Any tip for optimizing render for animation: image sampler and anti-aliasing setup, GI, textures, global switches ... is welcome!

 

I am planing to make "to do list" on this subject and it would be nice for all to have one topic with all ideas in it!

[Nic H]

very hard to say without seeing a frame and rendertime and machine spec

5mins is pretty fast for a frame (what size - 1280? or 1920? )

 

typically / very generally - its the image sampling that will slow you down the most - as long as you aren't topping out on ram. then displacement and raytracing reflection / refraction that will also have a big effect.

 

i deal with giant scenes quiet often so more info and i can try help out!

[denic]

Maybe I didn't say it right .. length of finished animation needs to be 5 mins (1280x720x25fps). So with 25 fps I need to render 7500 frames for whole animation and because of that - every minute per frame is important to me.

So far, render time for close ups (2-3 building) is 20 mins. Much bigger problems are shots of complete area with all the buildings - 70 mins per frame.

 

Buildings are converted to 8-9 different vray proxys.

Trees are iCube iTrees - 500.000 tris per tree - also proxys 300, pieces

Grass scattered proxy- vray double sided material - reflection only specular

So far I'm avoiding any displacement and refractions in scene.

I am planing to bake GI solution IR + LC for walk-through animation.

Image sampler for now Adaptive DMC min/max 2/5

 

It will be rendered on AMD X6 ( 6 cores ) with 8 gigs of ram, 64 bit win 7.

 

I'm hoping that your experience with giant scenes will help a little bit!

 

And here are some early test 3D models and renders...

 

 

 

 

[Nic H]

Id say its the vray scatter 3d grass that is making your frame times a bit longer (allthough to be honest those times seem reasonable on your hardware) on the close in frames.

 

7500 is an awful lot of frames to render! I cant possibly imagine you need 5 minutes to show that development. i suppose its too late for a edit though.

 

Can you break it up and optimize each section or is it one continuous path?

 

Your DMC settings are pretty low as well, and you have reflect turned off for the grass so im at a bit of a loss as to how to make it render quicker sorry. Can you use an external render farm?

[aaronrumple]

70 min per frame is pretty good for a scene like that on said hardware. Drop the grass scatter as it will burn time and probably not really add much at the animation size and with motion blur. You could add it in for few seconds if you really are up close at some point.

 

Outside of that - you need network rendering. If you don't have it yourself - you can rent: http://www.rebusfarm.com/render-farm-home-ppc_en.html?gclid=CIq-2u61kqQCFRFW2godtiiuHw

[denic]

Tnx, but....

My question is not related to hardware at all. Even if I use any render farm services, I can dramatically cut expenses if I optimise properly render setup.

 

Take for example Rebus costs calculator:

render time per frame 20 mins x 7500 frames = 3722 $

render time per frame 15 mins x 7500 frames = 2791 $

 

So good render optimization is the issue here also (and/or money saver).

[Devin Johnston]

You can try excluding all of the glass from the GI, go into Vray properties and turn "Visible to GI" off. You can also try not having your grass and trees generate GI, those two things should decrease your render times. You should also post your GI settings so we can see if they can be tweaked. If your looking for a much much cheaper solution to the Rebus render farm send me a PM.

Edited September 21, 2010 by Maxer

[Nic H]

but the GI will be baked and is generally very quick to precalculate - depending on how gigantic the camera moves are you could do it every 25th frame.