opacity map alpha channel

[fish]

Well this question goes somewhere between textures and rendering:
I have a tree with opacity maps on the leaves (which are simple quads). Standard material, default scanline (i'm only outputing the alpha channel now for comp)

How do i get the b/w bitmap on the opacity channel to affect the alpha output? Cause i can't comp the rendering right if the leaves come out as rectangles in the alpha render.

Please help

[zek0]

In opacity map go to bitmap parameters, find "Mono Channel Output" and set it to alpha.

[fish]

i can't, its disabled.
The jpg i'm using for the opacity is a 24 bit bitmap

Should i be using a png or tga with an alpha channel or shoud i be using a grayscale bitmap on the opacity channel?

[zek0]

Yeah You need to use a format that supports alpha channel, png or tga or anything else with alpha channel.

[poopipe]

you can use a separate greyscale bitmap in the opacity map - in Max at least.