shadow splotches Vray sun/sky

[Guest]

I have been pulling my hair out over this. No matter what setting I change the splotchy shadows wont go away!

Lighting = VraySun
Adaptive DMC = min 1 max 16, Clr thresh 0.01
Vray Environment override = VraySky
Colour Mapping = Linear
IR Map = min -5 max -2, HSph. subdivs 150, Interp. samples 20
Light Cache = subdivs 2000, sample size 0.2, scale world
DMC Sampler = adaptive amount 0.85, noise thresh 0.002

All subdivs for materials and shadows are at least 32. Am I missing something?

[kein_plan]

hi, are you sure, that it is your shadow? it looks like double faces. is there some double geometry ?

[Guest]

I checked, even re built the roof from scratch.

[super gnu]

could it be you have "store direct light" turned on in the lightcache and thats causing it somehow? does look like double faces, but also looks like a crap lightcache.

[Guest]

nope store direct light didn't change anything.

I do have vray light materials in my scene, would that cause it?

[Guest]

I still cant fix it, it wont go away

[Subburb]

My suggestion :
Try the "check sample visibility" into the irrmap options
If it don't works, i'm pretty sure that the Irrmap Detail enhance will greatly help.

about LC : if you're with Vray 2.0, you can try to check on the "retrace corners" option.
You can also switch to screen mode (0.01) to avoid too much inconsistent samples in this area.

[super gnu]

have you tried to pin down the problem yet, you seem convinced its the sun shadows, but it looks very gi-ey to me.. do you still get the same effect without secondary bounces? without gi at all? (you might need an ambient light in there to see)


hows about if you override the materials in the scene/ hide the sunshade?

did you try playing with the secondary ray bias set to say 0.001?

als what is your sun shadow bias set to? try 0.001 or something... process of elimination... innit :P

[fAEkE]

Looks like the sunshade planes above the artifacts are highly reflective, can it be reflective GI problem? Maybe try an override material and set the GI material to standard vray matl 75, 75, 75 or something.

[Guest]

I ran out of time and had to get it out the door, so had to brute force it instead. BF + LC is ok, so it was something to do with the IR. When I get some free time I will go back to it and see if I can find the problem.

Subburb, I tried all your suggestions and none of them worked.

Thanks for all the help.