• VEGAS Pro

  Alpha Matte from Softimage XSI

  Posted by John Estes on June 23, 2009 at 2:42 am

  I am a user of Sony 8. I am trying to bring a Alpha matte still sequence over from Softimage XSI with the expectation that the figure is isolated and the black will become transparent. I am having trouble for some reason. Prior I had poser that would render a .tif image sequence that would allow transparency ( with I believe just a change of the import to premultiplied or one of those options). I think vegas recognized it without any import selections.

  I have rendered the alpha matte file and tried .tif, .png all with no transparency generated. Is it because it is a 8 bit image? I have tried all import options. The image I am trying to use the alpha channel on is black background with a single subject ( generated in 3d) on it.

  What am I missing? I used the compositing mode button and have tried all combinations including 3d source and alpha source. I have been trying any combo I can think of so any help is welcome. I am a beginning to intermediate user of softimag e. Is there any way I can check the alpha on one of the stills to ensure that it is alpha black, not just solid black?

  Thanks, John

  John Estes replied 16 years, 11 months ago 2 Members · 2 Replies
• 2 Replies

• 

  Steve Rhoden

  June 23, 2009 at 3:01 am

  When you import the image sequence or when you right click
  and bring up the media properties….did you change the
  alpha channel to straight (unmatted) or premultiplied? etc.

  Steve Rhoden
  (Cow Leader)
  Creative Arts Director and Film Maker.
  Project Samples at:
  http://www.youtube.com/hentys
• 

  John Estes

  June 23, 2009 at 3:46 am

  Steve,
  Thanks so much for your response.
  I actually ended up just solving the problem.

  Mental ray has a image output selection drop down box.
  It has a drop down for choice of image, choice of format( RGB) and choice for bit (8).

  I had changed the file to .png but I did not realize until just now that there is a selection for RGBA that is in addition to the mental ray pass default which specifies RGBA as the heading for that pass, but obviously, the file format must be changed to the same. Not intuitive but it is the way it is.

  Now the file opens without any changes to be transparent in the background.

  If only I had a penny for every hour wasted on that one.

  Thanks again for starting to help me there. It is appreciated.

  John

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