Vray render settings (GI,IS...)

[rollsroll]

Hi,

 

 

Maybe my questions were answered sometimes before, but i'm little bit confused with Vray render settings.

So it would be very helpful for me if you can summarise my questions :

 

 

1. Is there any connection between GI (LC & IRR) and subdivision settings on lights ?

I tried to compute only light cache or IRR pass and change subdivs on vray lights in scene, but it takes no effect.

 

 

2. How are image sampler, GI settings and light subd. settings affecting each other ?

 

 

3. Why lightcache is computed before IRR, even if it is set for secondary bounces ? I understand that IRR using informations from lightcache, but lightcache compute first bounce too ? I though that the ray comes from light (direct light) then hits object in scene (first bounce) and then every other bounce is computed as secondary bounce. So why are secondary bounces computing before primary ? From where have they information about first bounces ?

[Francisco Penaloza]

I would recommend to go to chaos group website or VRay website and read the manual and tutorial introduction, they will explain all these

http://help.chaosgroup.com

[rollsroll]

i can´t find answer for my 3th question - why lightcache is computed before IRR ... ?

[Devin Johnston]

Question #3 is something Vlado would have to answer but I'm not sure why it matters that's just the way Vray works.

[Francisco Penaloza]

Thou I agree with Devin, from what I understand.

The calculation of light is not from light to object only, it is a little more complex than that, it also uses the camera position and usually there is rays from the camera to object and rays from light sources to the objects and so on.

GI or global illumination, is the bounced light or ambient igniting that you get I real life, for VRay this calculation is separated I two stages, but they still work together.

LC is like a rough pass of GI then IRR take that info and refine it. You could actually only use IRR only or LC only, or Brute force only but the overall calculation time will be longer and not efficient, VRay is all about how to do it good and fast, it is very flexible, that's the strength of VRay.

http://www.aversis.be/tutorials/vray/vray-20-gi-methods.htm

 

For detail info go to chaos group website.

[Corey Beaulieu]

I agree with Fransisco....

 

As a Path Trace algorithm, the secondary rays would be calculated first; camera to object to object to light.

 

http://www.disneyanimation.com/technology/innovations/hyperion