Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: mikinik on 2014-09-21, 00:09:20

Title: glossiness reflection and smoothing groups
Post by: mikinik on 2014-09-21, 00:09:20

hi all! why there are differences in glossiness reflection?
it is correct, that there is a dependence glossiness reflection and smoothing groups?

Title: Re: glossiness reflection and smoothing groups
Post by: Ludvik Koutny on 2014-09-21, 00:50:00

It is not glossiness. It is that when smoothing is off, those flat polygons reflect only very small portion of HDRI, and since your HDRI does not have very high resolution, it is filtered, and looks blurry.

Basically, when smoothing is on, polygons reflect quite wide angle of the environment. While when smoothing is off, polygons reflect only area that is perfectly perpendicular to the surface.

I am also attaching picture to better explain

Title: Re: glossiness reflection and smoothing groups
Post by: romullus on 2014-09-21, 00:53:27

I think it could be just lack of resolution of your enviroment map. On convex surface reflection is much smaller than on flat surface, hence it doesn't look so blurry. Try to place some geometry to reflect and see if its blurred by the same ammount.

edit: ninja'd

Title: Re: glossiness reflection and smoothing groups
Post by: PROH on 2014-09-21, 01:35:51

Yes, reflections is angle dependent. When smoothing groups is on the reflection is being calculated as if the object was round (even though it's actually flat).

Title: Re: glossiness reflection and smoothing groups
Post by: mikinik on 2014-09-21, 16:41:23

Rawalanche, thanks!
romullus, yes, from some geometry glossy reflections appear correctly.

Title: Re: glossiness reflection and smoothing groups
Post by: maru on 2014-09-21, 17:47:30

Most simple explanation from my mind: when smoothing is off, flat polygons behave like flat mirrors.