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View Full Version : Controlling a shader transparency with ramp


nelsonteixeira
10-28-2009, 10:53 PM
I need to control a blinn shader transparency using an animated ramp to make an object disappear... the thing is when I plug the animated ramp to the transparency slot.. the specular information still renders... I could plug the ramp to the specular channel, so I could get the specular go out also, but the issue is that this connections is already busy with a specular texture map.
How can I get around this?? I miss a global transparency atribute that would vanish all visible information!

djx
10-28-2009, 11:20 PM
You can use the layered shader to do this (even though in this case you only need a single layer). Set the layeredShader compositing flag to "layer texture". Hook up your blinn to the color slot. Disconnect your ramp from the blinn and connect it directly to the layeredShader transparency slot.

-- David

nelsonteixeira
10-29-2009, 07:22 PM
Thanx David... that's right what I need!

Jozvex
11-01-2009, 01:09 AM
If for some reason you weren't able to use another shader besides the blinn, another couple of ways to do it would be:

* Stick a 'multiplyDivide' node between the specular map and the blinn, using the ramp as the second input to multipy with.

* Or use a 'blendColors' node instead of the multiply, where the first input is your specular map, the second is just plain black and the ramp goes into the third input ('mixer' or 'blender' or whatever it's called!).

* Or (last one I promise), if you don't want to use any extra nodes inbetween, just plug the ramp into the 'Color Gain' slot of the specular map's file node, under the colour balance section.

:thumbsup:

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