View Full Version : Remove alpha from image sequence

11-26-2004, 04:00 AM
Hi all,
Have done a search for an answer for this first AND gone through the tut on clip maps in Dan's cd set. but......
I have an image sequence (of nice flashing stage lights in Particle Illusion) rendered as 32 bit TGA (so they have a nice alpha channel)
i then applied this sequence to a nice flat box. but....
I cant seem to be able to "clip" out the background so the sequence plays without seeing the polygon of the box behind it.
Seems simple enough. What am i doing wrong?
thanks as always oh mighty LW gurus

11-26-2004, 06:13 AM
to remove alpha you can go to image editor and on alpha channel set "disable".
anyway i attach a sample of what you want to do.
particles image tga32 mapped on flat poly, check double use of image and i hope that help you to see where you did error.
good work

11-26-2004, 06:06 PM
I have been playing with this a little. I found that the image must be placed in both the color channel and transparency channel. By changing the alpha setting from enable to disable in the image editor will effect the color. I guess the alpha setting doesn't do what I thought it would do. You would think by disabling the alpha you would see the whole image versus a partial image with the alpha enabled.

11-27-2004, 06:26 AM
Thats why I got so confused. I thought the clip map would work it out as well. but no luck really. but by doing both those settings its working nicely. I just wish LW and After Effects worked better together.
But now I have that sorted out I am so confused about a "running lights" question...
oh well here goes...
thanks for sticking with this question and helping out!!!! i am always humbled by this list i must admit. I love it,
hope you're having a great weekend.
from a lightwaver in Africa (yes!)

11-27-2004, 08:51 PM
To get the clip map to work you need to think in luminance. For example black text on white background will show only the text. According to the manual anything over 50% brightness is removed and anything under is kepted. So clip maps do not use an alpha channel. It works like a chroma keyer, exept it is luminace instead of color . Which brings up another idea, you could create a solid background color and use chroma keyer by going to WINDOW>COMPOSITING OPTIONS... or ctrl F7. As far as I know though it only works on background and foreground images, not objects.