Occlusion And Displacement Problem

[meerkat]

hi,

i am trying to render an occlusion pass with displacements using this occlusion shader:

surface occsurf3(float samples = 64, maxdist = 1e30, coneangle = PI/2)
{
      normal Ns = faceforward(normalize(N),I);
      float occ = occlusion(P, Ns, samples, "maxdist", maxdist, "coneangle", coneangle);

      Ci = (1 - occ) * Cs * Os;
      Oi = Os;
}

it seems to work ok without displacement but when i render with displacement it doesnt look good, where am i going wrong?

thanks in advance

amir

[rjpieke]

i am trying to render an occlusion pass with displacements using this occlusion shader:

it seems to work ok without displacement but when i render with displacement it doesnt look good, where am i going wrong?

26148[/snapback]

Some initial thoughts:

Does it look any better if you crank up the number of samples? If it's a polygonal mesh, are you using N and Ng in your call to computenormal(), or only P?

Can you post the displacement shader you're using?

Cheers!

[AdamJ]

also check your shading rate.. it looks like it's set really low to somthing like 0.1... if not disregard

[Jason]

Good point - how many occlusion samples are you asking for? It's not uncommon to have 1024 for some scenes (!). Try 256.

edit: Ah, I see you're asking for 64. Yeah. crank it.

[meerkat]

here is what the vop net looks like. I have tried rendering with more samples and is still the same.

[rjpieke]

here is what the vop net looks like. I have tried rendering with more samples and is still the same.

26162[/snapback]

Hmm ... not sure what to immediately suggest. Does a diffuse/specular render look "ok"? Can you post your scene for us to play with?

[meerkat]

here is the file:

environment.hip

[rjpieke]

here is the file:

26165[/snapback]

Try modifying your occlusion() call to include "maxerror" 0.01

float occ = occlusion(P, Ns, samples, "maxdist", maxdist, "coneangle", coneangle, "maxerror", 0.01);

Cheers!

[meerkat]

thanks for the help.