PDA

View Full Version : Adding alpha channel

Tornado7
10-28-2009, 03:39 PM
Hi guys, I'm quite new in after effects...I rendered 2 images sequences from Maya; I need to use the first images sequence as rgb, while the second one as alpha information for the first sequence: both sequences are obviously rendered without alpha.
After I imported both in AE, I used the Set Channels effect and I set Source Layer 4 to my "alpha image sequence": my probem is that nothing seems to change and if I render everything out...but sequence has still no alpha; should I use another way to set my alpha or I'm doing something wrong using the Set Channels effect?

thanks in advance for any help ;)
ernpchan
10-28-2009, 05:26 PM
What are you trying to use from the 2nd sequence as your alpha? Is it a black and white sequence? If it's b&w you could use it as a luma track matte.

If you're trying to use one of the RGB channels in the "Layer 4" area of the Set Channels plug-in you need to set the "Set Alpha to Source 4's" drop down to something.

From there you could use your 2nd sequence as an alpha track matte.
Tornado7
10-29-2009, 09:15 AM
yes, the second sequence is a black and white rgb sequence and I selected it in the drop down menu but nothing changes in my alpha channel that is still solid white...
Mylenium
10-29-2009, 11:55 AM
Check your render settings. Enable RGB+Alpha and also of course chose a suitable format that supports alpha...

Mylenium
Tornado7
11-01-2009, 10:48 AM
Yes, I saved it as Tiff image sequence including alpha, but the final result is a white solid alpha channel...
CGTalk Moderation
11-01-2009, 10:48 AM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.