tasks on surfaces

[seblezinzin]

Hello,
I didn't find answers on the forum to my question, so I ask you :
I've a  Problem with some surfaces, I've "tasks" :


I tried to change meshs of the surfaces, check normals, change material, change environement, reduce the reflect ot the material....

The only way to success is to render in real time but it's so longer....

Thanks for any informations

[seblezinzin]

No ideas

[DriesV]

Have you tried increasing the samples (say to 64) in advanced render settings?

Dries

[seblezinzin]

Yes, I tested to increase samples, but no better results

[DriesV]

Have you tried increasing the global illumination quality in advanced render settings?
Maybe you can set it at a value of '3' and see if that improves the surface quality.

It seems to me that you're only getting the 'flaky' appearance on under-lit surfaces. You could also add some simple geometry with the Area Light Diffuse material applied to act as fill lights. You will get much cleaner surfaces when your model is fully lit.
At least in my experience advanced rendering often gives undesirable results when the scene is underlit (f.i. HDRI-only lighting with lots of indirect illumination in interior scenes).

Dries

[PhilippeV8]

Are you sure your material doesn't have a bumpmap, opacity map or ambient map that creates this effect ?  Maybe it looks all white in photoshop, but with more contrast in your KS scene, they show up.
Just a thought ...

[seblezinzin]

Thanks for answers, but it's not this.
I increased the global illumination, the surfaces are clean (simple surfaces made with Catia), and I've not bumpmap or any other map. it's just the paint material in the keyshot library

[seblezinzin]

I found the problem 
It's the global illumination option, I should uncheck the option.