opacity map alpha channel

fish · 12-11-2007, 07:40 AM

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 · 12-11-2007, 08:35 AM

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

fish · 12-11-2007, 09:05 AM

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 · 12-11-2007, 09:22 AM

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

poopipe · 12-11-2007, 03:31 PM

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

12-11-2007, 07:40 AM	#1
fish Registered User Join Date: Oct 2004 Location: Romania Posts: 108 Thanks: 0 Thanked 0 Times in 0 Posts	opacity map alpha channel 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 __________________ I do 3 kinds of work: GOOD, FAST and CHEAP. You may choose any 2. http://www.fishstudio.ro

12-11-2007, 09:05 AM	#3
fish Registered User Join Date: Oct 2004 Location: Romania Posts: 108 Thanks: 0 Thanked 0 Times in 0 Posts	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? __________________ I do 3 kinds of work: GOOD, FAST and CHEAP. You may choose any 2. http://www.fishstudio.ro

12-11-2007, 03:31 PM	#5
poopipe conscientious objector Join Date: Sep 2007 Location: cambridge, uk Posts: 4,234 Thanks: 3 Thanked 126 Times in 120 Posts Awards Showcase Total Awards: 9	you can use a separate greyscale bitmap in the opacity map - in Max at least. Last edited by poopipe; 12-11-2007 at 03:34 PM..

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12-11-2007, 08:35 AM	#2
zek0 Registered User Join Date: Oct 2005 Posts: 22 Thanks: 0 Thanked 0 Times in 0 Posts	In opacity map go to bitmap parameters, find "Mono Channel Output" and set it to alpha.

12-11-2007, 09:22 AM	#4
zek0 Registered User Join Date: Oct 2005 Posts: 22 Thanks: 0 Thanked 0 Times in 0 Posts	Yeah You need to use a format that supports alpha channel, png or tga or anything else with alpha channel.

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