Alpha -> Colour

[TheNeverman]

Sounds fun....
So was there a question in there?...

n8

[Ithuriel]

Intro

im making some image planes for a modelling project.

Question

I was wanting to make a onion skin effect for the images colour channel to be mapped as a alpha channel.
I remember reading that you can make onion skin image planes in photoshop, and was wondering how to do this?

I remember that it had something to do with mapping the colour channel as a alpha or somthing? any ideas on
A) what im talking about
B) how to do it

cheers any help would be grand

[Skjoldbroder]

not really no. what are you trying to achieve, why, and through what means?

[halo]

are you talking about perhaps copying line art into an alpha channel and then turning on the alpha channels preview so you can see it over your image?

[Ithuriel]

Kinda...

Lets say i have a photo, which i want to use as a refrence for modelling.
I want to be able to place it onto a nurbs plane (hardware texture shaded) so i can see straight though the image and model straight on top.

i want the image to be transparent. and the color channel to be kinda like a onion skin or alpha channel, so i can see though even the colors..

attached image as a example...

http://cgc903f.ifreepages.com/onionskin.jpg

or...
if image doesn't load
http://cgc903f.ifreepages.com/onionskin.jpg

[franklyn]

why dont u just adjust the opacity of the material in the modeling program :S ?

[Ithuriel]

Thats what i have been doing for the past 12 months whenever i have been modelling,

but when i saw this idea i thought, hey that looks funky... give that a burl next time, and kinda never got around to it, besides which my photoshop skills aint tip top.

but its no drama, was just curious if anyone knew how to do that same sorta effect

[Skjoldbroder]

ah right, that makes more sense.
yeah, i've been doing that a few times. If you're using a quite clear linedrawing or blueprint without gradients and weird stuff going on, you can just use the image itself as the alphamap on a plane, yeah. (to work like a stencil, basically)

[Ithuriel]

excellent...

so how do i make it a alpha map in photoshop...?

but then again i can just do that in maya, import the file and input the color to the alpha of the texture yeah?

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