Light Cache and IR map problem

[jacksc02]

Hi everyone,

Im having a problem using light cache with irradiance map, im not sure if it is a bug, or if its something im not doing right.


This first image is the Light Cache calculation, it looks good


This second image is during the Irradiance map calcualtion, it looks too dark


This third image is the rendered image with 1000 light cache samples, it looks like it hasnt renderd the secondary bounces.


This fourth image was rendered with 700 light cache samples and everything rendered fine.

If anyone has any suggestions please let me know

[natty]

Yeah i had the same problem today .. i thought i was going mad .. obviously not.. and it was due to invalid lightcache samples... what caused i dont know as yet.

[jacksc02]

Thanks for reply Natty, I thought i was going nuts too

hopefully Vlado has an answer

[natty]

It would seem that the light samples become corrupt and unusable and then vray doesnt have a second bounce calc? odd ..

[corey]

Make sure that your light cache sample size is set to a larger 0. After playing around with PPT I discovered that calculating a single frame light cache map with a sample of 0.0 results in an invalid light map. So I returned the sample size back to default and all is fine.

The only problem is that you cannot save an unbiased light map (sample size 0.0) when using the PPT method. You have to set the sample size to .000001 or something like that.

[natty]

im getting this without using PPT .. this is just lightcache..

[jacksc02]

yeah same here natty, my sample size was set to .01 and it was just light cache

[jujubee]

Does this only happen at 1000 samples?

[corey]

I agree there is something going on. I did into a similar problem as you guys last night. I was just able to reproduce the problem when setting the sample size to zero. So, I know it's possible to encouter this simliar if not same problem if people are changing the sample size zero and forgetting it there. After setting the sample size back I have not had a problem since...

How are you guys calculating your light cache map?

[jacksc02]

1000 and above

[vlado]

You probably get an invalid color somewhere along the process, which then propagates throughout the scene and sucks up all of the lighting (that's GI for you ) Look at the VRay messages window to see if you are getting any "overbright or invalid color" warnings.

Best regards,
Vlado

[jacksc02]

ok, thanks for that Vlado,
What is the best way to get rid of overbright o invalid colours?

[natty]

... well im getting an overbright and invalid colours on every object in my scene all of a sudden ?

[Gijs]

I also noticed that overbright or invalid color warnings seem to increase in amount when lightcache samples get smaller...

[jujubee]

I've been getting random overbrights as well - may or may not be related but I especially took a major hit (a big list of them) when I switched over to IR Buckets when rendering DR. Rmove the 'buckets' and it went away...