Hi all!
As a newcomer I have a question on the materials. Image a simple wall: when it is hit by a light beam it spreads its 'color' all around (so, it's really different if you have a reflective dark green wall instead of a matte white wall). In Kray the amount of 'light' spreaded from the wall surface is generated via the diffuse channel, via the reflection channel or by both?
And, in the third case, what is the amount of the light, emitted from the diffuse, different from the reflection channel?
Hope I could explain the problem...
Many thanks
Last time I took decision keep diffuse level 100% (if material has 20% reflection I reduce diffuse to 80% - to keep always 100%)
If You have green , red or another "strong" colour of course You will receive strong GI color effect . Then You can use desaturate shader to reduce this bad effect (V-ray also has it). Of course transparent surfaces do not reflect many photons because some of them go through the transparent material...so also You have to reduce diffuse level.
Kray takes information also from colour , if wall is almost dark You will kill all photons.
lav wrote:Hi all!
As a newcomer I have a question on the materials. Image a simple wall: when it is hit by a light beam it spreads its 'color' all around (so, it's really different if you have a reflective dark green wall instead of a matte white wall). In Kray the amount of 'light' spreaded from the wall surface is generated via the diffuse channel, via the reflection channel or by both?
And, in the third case, what is the amount of the light, emitted from the diffuse, different from the reflection channel?
Hope I could explain the problem...
Many thanks
Kray calculates amount of reflected light basicly by this equation:
Color * Diffuse + Reflection
So you can see they all contribute to the reflected value. And if you calculate those values together they should not exceed 100% (if you want to stick to physicall accuracy). So this means that if you increase Reflection value you should decrease diffuse or color value to compensate. Of course once you start adding transparency and translucency this gets a little bit more complicated but this is the basic idea. More on the topic can be read on Kray Wiki.
So, to make the subtle reflection blur on a painted wall I can use reflection channel with reflection blurring (with a incidence angle gradient as input)...
As a second question, I have a doubt, cause in the repository of materials (here in kray site) I found some materials with specularity channel active, even if deprecated.
And I have a lot of troubles in obtaining the beloved effect in Kray.
lav wrote:So, to make the subtle reflection blur on a painted wall I can use reflection channel with reflection blurring (with a incidence angle gradient as input)...
yep.
lav wrote:
As a second question, I have a doubt, cause in the repository of materials (here in kray site) I found some materials with specularity channel active, even if deprecated.
And I have a lot of troubles in obtaining the beloved effect in Kray.
Specularity is a funny effect... It acts as if there was a real model of a light source in scene. It fakes this by creating a bloom on the spot where light reflects from the surface.
To get similar effect with using just reflection you need to model the light source. This may be feasible for artificial light sources but you probably won't go about modeling the Sun. So there you can use specularity to get the "fake reflection" effect from the sun light.
There is also a third option: enable "Trace direct light" on Kray quality tab. This will have similar effect as if your light sources were visible area lights - they will show in reflections.
