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Leftover
03-30-2003, 10:56 PM
Since i started to explore XSI i've noticed werd color cast on colored reflections. Looks like it comes from blending reflection and diffuse buffers...
Finally i've found solution which gives correct render output.
But i feel completely dumb now, i don't understand a logic of what's going on and how it works...
Is this color cast bug or feature? Could anyone explain how to make correct colorized reflections and how it works?

There's illustration of shading network:
(Scene contains 2 spheres: big one with checkboard texture and small one with reflections)
1-st way looks logical but it doesn't work
2-nd way is failed attempt to use separate "reflection" node
3-rd way which actually worked.

http://ok.vtc.ru/xsi_ref.gif
belly80naz
03-31-2003, 02:09 PM
I think it's a feature, but I don't use it too, I prefer to use only a gray scale reflection, That it's a normal reflection in a real world.
frumpy_bunyin
04-01-2003, 11:01 AM
You're doubling up your reflection.

The reflection node you're using is generating a reflection (multiplied out by the incidence), and then you're passing that reflection onto the phong node telling it to be reflective based on that.

You may want to get rid of the reflection node and plug your gradient straight into the phong node.

Or use a mix 2 colour node and screen in the reflection after the phong node, and into the surface of the material.


FB
Leftover
04-01-2003, 06:52 PM
belly80naz: Actually there are colored reflections in real world... a good example is christmas-tree colored glass balls... and this inverted color cast happens with refractions too...

frumpy_bunyin: if i connect gradient node directly to phong i get weird inverted color cast....
belly80naz
04-02-2003, 06:59 AM
Originally posted by Leftover
belly80naz: Actually there are colored reflections in real world... a good example is christmas-tree colored glass balls... and this inverted color cast happens with refractions too...


Oh, yes! You're right:thumbsup: , but I think that in the more or cases the color distorion of the reflection is very very low. (nearly zero)
frumpy_bunyin
04-02-2003, 09:32 AM
What on the gradient are you plugging your incidence into? You're basic tree seems to be a bit askew.

The reflection node has an input (it's base colour) and then has a reflection amount, this tells it where to reflective, it takes a reflection sample and a reflection is generated at this point.
You're then using this reflection sample to tell the object where to be reflective, where it takes another sample. You're doing it twice.

Screen the reflection in after the phong node and see if that gets the results you want.


FB
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