Irradiance map weird artifacts

[BinaryRay]

I have met with these weird situation before when using irradiance map and the only solution i have is turn primary bounces to brute force which works flawlesly.

 

Anyone has any ideas when these artifacts appear?

 

The scene is lit with vray sun and sky and the material is a simple gray.

Even when i crank up im values the problem persists. any ideas?

[luthias42]

what is your secondary bounce set at?

 

I usually get some good results with irradiance primary, Light cache secondary.

[ScottDeW]

Could you post your settings for Primary and Secondary? It also could be a problem with the geometry. I've noticed issues if my mesh has any stray verticies running around in it.

[BinaryRay]

the model was imported from revit so it is accurate, even though i tried to merge the geometry, align it, split it etc. the problem persists. It is not a geometry problem because brute has no problem with the scene.

 

The artifacts disappear (not completely) when i use very high irradiance map values for both subd and interpolation.

 

The scenes above were rendered with brute + lc and im + lc.

[Alyosha]

My first guess would be geometry. Since the geometry in question is very simple, I would encourage you to recreate it (not just attempt to fix it but create it from scratch) in max and see what happens, for the sake of learning about the problem, if nothing else.

 

Because this really looks like geometry flaws to me, havent seen such irradiance splotches before.

 

And you don't know if it's not a geometry problem if brute has no problem with the scene - definitely worth a try imo.