Odd artifacts in render

[n4vdeep]

Hi everyone at odforce

 

I am rendering an ocean in Houdini 13 for a sim, after shading and lighting the ocean I get these odd little white squares in my render, just wondered if anyone can help in identifying why this is happening?

 

I don't know if this is a GPU issue? I mean my GPU isn't the best but its not the worst either, its a nvidia GeForce GTX 660 Ti which is fully up to date drivers wise.

 

I have attached some screen shots.

 

Many Thanks

 

Nav

[SSFX]

First of all your GPU has nothing to do with this issue since mantra is not GPU accelerated or anything. From the screen grab, I would say its probably fireflies in the specular. You might try to clamp the high values of your bounces by reducing from 10 to 2 your color limit in your mantra node. You could also try to increase your sampling quality from 1 to 3 on your env light, assuming your using some kind of IBL setup in your scene. If this still does not work post your scene so we can take a look.

[Skybar]

Try upping the reflect roughness/equivalent to something that isn't 0.

[n4vdeep]

Hey Guys

 

Tried your suggestions but this didn't work either.

 

I have included my scene file, maybe you can help me work it out?

 

Thanks

 

Nav

breechFX15.hip

[fathom]

first things first.  you should render with additional image planes to help you diagnose the problem.  in your rop, add direct and indirect and then toggle on both the "per light" exports and the "per component" exports.  that will give a pretty good assortment of different image planes to track this down.  indirect channels all refer to secondary rays (refractions and reflections and gi bounces(?)).  direct refers to primary lighting only.

 

the specs are likely in the direct_reflect (spec).  if so, then you should might consider adjusting your material's specular properties.  or upping samples could also help.  blocks like that are typically VERY high spikes that infect neighboring pixels based on the pixel filter size, so sampling probably won't really help much.

 

for oceans, i like to use a dome environment object for the reflections.  i use the env light only as a diffuse emitter and then add a real sun light also as a diffuse only light for some added control.  then i'll typically clamp the high values in the shader on my environment dome (object) so the sun area doesn't get too hot (like clamp at 1 is usually fine).