Material GI Control

[Chris_Jones]

I would like it if the gi control for gi multiplier was better integrated into the vray material, as most people ignore the important aspect of gi control due to the use of 2 materials to do it, it shouldn't be that hard either.
What i would like it there was a summation of energy of somesort for the materials, so that diffuse+absorb+reflection+refraction=total light hitting, so you get even better materials due to their more correct aproach to the way they interact with light.

[natty]

are you talking about GI send and recieve ?
this can be done in the vray object properties, or a material wrapper.

[Geddart]

I agree with you Chris_Jones,
I'd like to see a Spinner for the Amount of reflected energy in Percent too. Lightscape, Max Radiosity and other renderers that are used for Lightplanning have it too. The thing is that a white Wall and a white Table both have the same color but they do not reflect the same amount of energy. We have sheets with reflectance values for various surfaces - they're in the Lightscape Help too and it's exactly what the Architectural Materials of Max6 are for.

Right now Vray calculates the Amount of reflected Energy alone from the RGB color what is obviously wrong. I really like to see a more accurate approach to the GI properties of surfaces and more control for the user like a "GI" Material. (Red Object bleeds blue)

Where one would implement those new spinners is somewhat questionable. When we took out all the GI controls out of the Wrapper, only Matte controls are left. Would be cool to hear the voice of the people here.

[natty]

Ahh ... i understand, yes that would be good.

[tom schuelke]

Hi

Same opinion here.

My experiance is, that an energy control, that gives you a feedback for the overal energy a material reflects in the scene gives you a very good control over the brightness in the scene. right now for controling the traveled way, the depth to which light goes into a scene depends, like Geddart told on the rgb values.

there are only two physical incorrect ways by the moment to change this. first, change the object color. a brighter material will reflect more "energy", like vray would understand this. but this leads to wrong object colors.

secound, use exposure controls. this also doesnt solve the real problem, of incorect energydistribution of reflected light.

a wrapper would solve this. you would exactly get the color you need, on objects, but still could change the depth, light would would travel into your dark areas, before getting absorbed.

at the moment the object GI multiplier dont solve this realy. by multiplying the Gi amount you can get very unpredictable results. you can make a material reflect 110% of the incoming energy, so that in holes, and areas you can get some sort of blown out incredible strong lights where there should be shadows.


my suggestion.
in the first step, vlado could implement only a counter that gives you a feedback for the effectivley reflected energy. for example if it is 90% or 50% or something like that. this would work together with the actual gi-multiplier, but would give you predictable feedback, for not getting such overbright areas.

secound you also could need presets for realistic reflection scales like the max 6 architectural material has.

third, reflections i would like to see more accurate reflection values as in max radiosity, that calculates diffuse lightreflection of objects allways as diffuse, which is wrong for realworld materials.
highend lightplanersoftware usualy has got further options , to mimic realworldmaterials, for example , the possibillity, also to calculate partialy diffuse and also specular energybouncing from surfaces.


well this sounds like more options to handle, and more work to do, when setting up the scenes, and so for an artists point of view doesnt seem to fit what he wants.

but this in my opinion is wrong. When you get some presets, and use this, you very very fast get very realistic light distributions in your scene, and get better control of what you want. i was surprised, how fast, you can get a ralistic lightsetup, once you understoud the max radiosity or lightscape. you nearby havn´t to think anymore about it.

i am sure vray would be able to handle such things much better than maxradiosity, and some smal more buttons would save us all much much time, we usualy use, to fake ralistic results, by using exposure settings, and other fake solutions.

and for more, it also could open the door for accurate physical renderings.



Tom