so i want to render an object and in front there is mirror. what i want is that alpha of that object on the reflected surface..eg suppose there is window and in side of that there is mirror and window is reflected on the mirror.Now i want from the mirror is only reflection of mirror and alpha of only the window that is reflected...
pls feel free to ask any questions.
where do you want that to happen?
i can't imagine the scene you're describing but generally speaking maybe applying flat black and white materials and rendering that would generate a mask you can use from the scene.
does your software have a Matte/Shadow material, you should be able to render the shadow cast by the window into the alpha channel.
the thing is the window will not be directly in contact with the mirror so i dont think it will produce alpha channel.
maya (if you mean in which i software)
i have downloaded this from google but this shows what i want sorry i should posted this with original post
now as you can see there is a ball and mirror 1 and mirror 2 are reflecting the ball.
i want the alpha of the ball in middle and only the alpha of redlected object .right now what i am getting is alpha of the ball in middle and a square alpha of mirror instead of that ball only..
hope you now get the point.
i mean its a bit hacky what killnpc said, but yeah. what if you just apply a white material to the ball in the center, make the scene all black and have the mirror only mirror the white ball, that way you'd have a mask for that.
so if i understand you correctly, you want an alpha (or mask) that would look something like this:
yup!! and i don't want the black and white image separately the image should have this as an alpha channel when i export it in tiff or png..
yes i could do that and ultimately have to do that only ....but i was looking if anyone have some other techniuqe..
i have to use that black and white image in photoshop to cut alpha.
What renderer are you using in Maya? Many modern renderers like V-Ray have AOVs (arbitrary output variables) which can automatically make masks like this.
i am using arnold renderer.