Use background, Alfa in alfa. Maya textureing help needed.

[Jerakin]

Hi.

I have posted some days ago about my school project. We are trying to recreate wings. Like the guy in X-Man. It is soon done, but I have uncounted an problem.


I want to do a Shadow Pass, thou I use an alpha texture to get an extra definition on the edges. Because I wanted to have the rendertime/polycount low.
The computers we use isn't the best and we don't got an render farm to use.

I use to do the shadow pass by using an "Use Background" shader, setting:
Specular color to black
Reflectivity to 0
Reflection Limit to 0
Leaving Shadow Mask and Matte Opacity to 1

If I do this way I get the Shadow information in the Alpha Channel.

So the problem is then of course that I don't want any Shadow information on the places where the color is removed by the alpha texture.

Now you are thinking "Ah just use the alpha from different Render pass, like color."

Unfortunately that won't work. Because we got feather above feathers and that feathers are casting shadow on the feathers under them.
But it is the whole feather that is casting a shadow, not only the part that is visible in the Color Pass or masterLayer.


So now that the problem in explained I would really love some help. Do someone know of an way to render a Shadow Pass, but get it cut outed by the alpha texture?


Thanks in advance.
Jerakin

[McKronic]

Try texturing your feather alpha into the matte opacity of the use background shader.

[Jerakin]

Try texturing your feather alpha into the matte opacity of the use background shader.

Tried it, and it didn't work. =(

[McKronic]

could you post an image of your feather alpha and the result your getting?

[Jerakin]

could you post an image of your feather alpha and the result your getting?

I sure can.

So. This is the alpha texture of the feather:
http://img826.imageshack.us/img826/2260/featherapha13f.th.png (http://img826.imageshack.us/i/featherapha13f.png/)

And this is the result that I am getting.
http://img52.imageshack.us/img52/7092/shadow02.th.png (http://img52.imageshack.us/i/shadow02.png/)

As you can see, the whole feather is casting and receiving shadow. That isn't the result that I am after. I want the alpha not to cast or receive shadow.

Maybe the "Light cast only Shadow" technique could work, do anyone know how I could achieve the pic look but with an alpha cutout?

[Perversonality]

This is how you do it in Max: http://www.cgarena.com/freestuff/tutorials/max/ambient_occlusion/

Not sure if it's directly possible to do that with MR in Maya but I can't see why not...

[Jerakin]

This is how you do it in Max: http://www.cgarena.com/freestuff/tutorials/max/ambient_occlusion/

Not sure if it's directly possible to do that with MR in Maya but I can't see why not...


I would think that it could work, for AO not sure how to achieve the effect thou. It is the shadow I got problem with.