Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: Bormax on 2014-12-29, 13:04:35

Title: anisotropic reflection
Post by: Bormax on 2014-12-29, 13:04:35

Hello!
I have a problem with anisotropic reflection. Is it possible to make direction of anisotropy related to the object local coordinates? "Anisotropy" and "rotation" parameters rotate the hotspot in screen coordinates and objects with the same material look different depending on their position and angle they are rotated.
Here are my examples and the material I need to imitate

Title: Re: anisotropic reflection
Post by: borisquezadaa on 2014-12-29, 17:14:18

Correct me if i'm wrong but it seems that anisotropy is always in world coordinates?.
You could do better trying the glossiness and bump approach for that material instead of.

Something like attached maybe can be useful, i didnt include hdr to reduce size of file.

Title: Re: anisotropic reflection
Post by: Bormax on 2014-12-29, 21:29:19

Thank you very much borisquezadaa for your reply, suggestion and for the shared file!
I had the question "Why anisotropy oriented in world coordinates if the reason for this phenomena is scratches on the surface?" always when I had to use this kind of materials on surfaces which are oriented not directly vertically or horizontally. In attached files you can see the render with the shader from your file - it looks good, but it's not the result I'd like to get in this project. Also here is comparison "bump vs anisotrpy" just to see the correct direction of specular spreading. And here I've taken few photos of brushed metal object lit by linear lamp to see how it looks in real life. It's funny, that anisotropy works correct on simple objects as cylinder.

Title: Re: anisotropic reflection
Post by: Juraj on 2014-12-30, 00:46:45

No sadly not, this is issue on Corona's part (as compared to VrayMtl)

But if you have daily build (at least I think it's unique only to DB) there is now Anisotropy rotation mappable parameter.

Title: Re: anisotropic reflection
Post by: Ondra on 2014-12-30, 02:27:54

no, I havent touched it in a while. it is the same in all builds

Title: Re: anisotropic reflection
Post by: Bormax on 2014-12-30, 10:15:08

Thanks for your replies!
I use Alpha 7.2 and Anisotropy rotation parameter is mappable there. It uses gray gradient to determine direction of specular spreading and it does it in world coordinates. It doesn't make any relationship between direction of specular spreading and orientation of the object with all it's microdetails which make this effect happened.