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raw-m
08-15-2010, 05:44 AM
Starting with an apology, I know it's a simple question but my searches bring me back 1000s of "chaff" results and I've lost my bookmarks....

What is a good rule of thumb between relationship wise between the Diffuse, Reflection and Transparency channels?

I'm creating a simple transparency effect with a gradient into the Transparency channel, an invert into the Reflection. I want to bring the Diffuse into the mix but not sure how to keep things "balanced".

This is really an exercise in trying to help me get up to speed using gradients - I find them really confusing!! When using as a simple black and white colour gradient to drive Incidence the black and white seems to swop behaviours depending on what channels I'm plugging them into, ie some channels the black is the alpha, others the white.. - it's driving me mental, but getting there!! :thumbsup:

zardoz
08-15-2010, 07:13 AM
from the kray manual at: http://www.kraytracing.com/wiki/Setting_up_Lightwave#Surfaces

The general balance rule that should be followed to avoid unrealistic materials is :

Color*Diffuse+Reflection+Translucency<100%

or a more complex version including transparency would be:

Color*Diffuse(100%-Transparency)+Transparency+Reflection+Translucency < 100%

Cageman
08-15-2010, 07:36 AM
For transparent/refractive/reflective objects I would use Dialectric Material, since it actually takes care of all of that. While it is good to know how to set it up using gradients and whatnot, Dialectric material is really a huge timesaver for realistic behavour for this type of surface.

:)

raw-m
08-15-2010, 11:47 AM
Love you guys!! Big thanks :)

Am I being daft, how do you Color*Diffuse?

MooseDog
08-17-2010, 05:53 AM
Love you guys!! Big thanks :)

Am I being daft, how do you Color*Diffuse?

computers (yes even computer graphics) ain't nothin but numbers :D for instance your color is 255, 163, 067, and you've marked your diffuse at 73%. multiplying away gets you 255(.73), 163(.73), 67(.73) or 186, 118, 48.

raw-m
08-17-2010, 08:16 AM
Man-alive, I only want make pretty pictures!! Thanks MooseDog, but isn't that returning 3 values when refl, trans etc are 1 value each?

MooseDog
08-17-2010, 05:30 PM
Man-alive, I only want make pretty pictures!! Thanks MooseDog, but isn't that returning 3 values when refl, trans etc are 1 value each?

just answering for the "color" part of "how do you Color*Diffuse". for the others, yeah, one number. remembering color=r,g,b for red, green, blue.