Speeding up the Prepass

[MegaPixel]

I've got a scene with some recently acquired Evermotion trees where the prepass process takes 4-5 times longer than the actual rendering process does and I'm trying to understand what factors (other than material settings) contribute to this? I've tried adjusting the VRAY Properties of the trees to reduce their subdivs and GI contribution, but that didn't seem to help. Is there a simple way to tell VRAY to put more precalc emphasis on some things than others? Is IR not really recommended for scenes with heavy tree & plant usage anyways? Should I just disable all the double sided materials that come in on the trees? Any tips would be super appreciated. Thanks! -Dave

[tashko.zashev]

Hi,

It will be difficult for me to help with this issue without the scene file and render settings. However, one option is to discard the Irradiance map engine and move to the Brute force one. For exterior renderings with huge amount of small geometries this might be a better approach.
Another option is to untick the "use irradiance map" checkbox for the materials used to shade the trees and force them to be brute-forced for the GI calculations.

[Laserschwert]

Another option is to untick the "use irradiance map" checkbox for the materials used to shade the trees and force them to be brute-forced for the GI calculations.

That's a very cool feature! Is there a way to get this option on a per-object basis inside the V-Ray properties as well? Having some objects excluded from the irradiance map and automatically having them rendered with BF GI would be very handy. Right now excluding objects from the irradiance map requires them to get some fake lighting to match the rest of the scene, and this would make things SO much better and easier.

Edit: Added this to the wishlist forum

[tashko.zashev]

Actually we have this option in V-Ray for Maya and now I'll make a feature request in our system to be added in V-Ray for 3DS max as well.

[Laserschwert]

Awesome! Thanks a lot

[thanulee]

Idk if this helps, but I ve noticed this too with evermotion files, and u need to double check the samples of ur mats (older vray versions had like up to 128 some cases) and some mats are also sss2 with many maps. Need to optimise scenes sometimes. Ofc the bf calculation on objects with tones of details is much more optimal than IM. If u scenes are detailed, bf eventually is better. cheers

[MegaPixel]

Actually we have this option in V-Ray for Maya and now I'll make a feature request in our system to be added in V-Ray for 3DS max as well.

This sounds like exactly what I was looking for and would end up being the quickest/simplest way to shut down processing time on the heavy merged-in assets when you are in a time pinch. Thanks to everyone else for your responses as well. I knew in the back of my mind that the long term answer would be to spend time reworking/optimizing the new assets to perform better, we just never budget enough time to do this.