HindSightStudios opened this issue on Mar 10, 2007 · 12 posts
HindSightStudios posted Sat, 10 March 2007 at 12:53 AM
... when I don't see one thing that controls the "Alpha" settings.
I've imported a PNG image which I know has a transparent alpha channel, so how do I key out the unwanted portion without haveing to go generated a separate "black and white" alpha image?
bruno021 posted Sat, 10 March 2007 at 5:36 AM
When loading a texture that has embedded alpha layer, Vue will recognize it and offer to load the alpha information in the transparency channel.
HindSightStudios posted Sat, 10 March 2007 at 1:46 PM
Yes but only when you go to the EXTRA TROUBLE of creating and embedding a "Vue style" alpha layer. Meaning a separate black and white alpha.
Most programs automatically embed a transparent layer when saved as a PNG or TIFF.
So surely Vue has some setting I'm missing that lets it take advantage of this transparent layer.
It makes no since for them to not use an industry standard.
bruno021 posted Sat, 10 March 2007 at 2:52 PM
No, Vue recognizes the embedded alpha in the tiff image, and offers to load it in the transparency channel. No need for a "Vue style" alpha, which doesn't exsit, btw.
Maybe you should check the alpha channel of your image in a paint program, to see if it is right.
I'm sure I'm right about tiff, but I never used png, so what you could do is save your png as tiff in a paint program, and see if it works then. If it does, then there is a bug with the png format.
HindSightStudios posted Sat, 10 March 2007 at 3:54 PM
Well I be damn! You're right. Now all of a sudden TIFF, TARGA and PNG work great.
I can't even re-create the problem I was having. So great!
I'm thrilled I'm wrong. Sorry I doubted you Vue.
Now if I could just get the multipass SHADOW image to export with a transparent background.
I keep getting the shadow background as solid white, then I have to select and delete the white from every frame. AND I made sure I selected Vue's "embed alpha info."
bruno021 posted Sat, 10 March 2007 at 4:45 PM
Cool! Now I wouldn't know about the shadow pass problem, never used it, do you also save as png with embedded alpha?
HindSightStudios posted Sat, 10 March 2007 at 6:39 PM
I've tried all three formats, same result. White instead of transparent.
It's got to be something simple that I'm not "checking" or "clicking." And by the way, I appreciate your help, I just added Vue to my pipeline a couple of weeks ago, so I'm still learning.
bruno021 posted Sat, 10 March 2007 at 8:26 PM
You're probably not doing anything wrong here. But if the alpha information is embedded in the shadow pass render, maybe you can use it in your compositing program? I'm afraid I can't help more in this field.
Polax posted Sun, 11 March 2007 at 11:00 AM
You can advantage of the automatic connexion of the alpha output to the grayscale of an image used as a texture to make decals out of images that have no embedded alpha (.jpg, bmp..)
For the shadows, if you need a .png of your shadows on a transparent background, you can use the Shadow mask created in the Multipass and use PS or similar to add it as an alpha channel in the rendered picture.(you'll have to negative it first).
Then, save the new image as a .png.
Paul
HindSightStudios posted Thu, 29 March 2007 at 9:39 PM
Ah ha ... here's the problem Bruno021.
Loading one image, Vue loads the alpha. But if you load a sequence of images, it DOES NOT.
So Polax, you've got the answer, but I couldn't quite follow your guide. I added the filter to the alpha side, but all I got was a semi-transparent image. It didn't seem to key out the white.
Is there a tutorial on this? And thanks.
Polax posted Fri, 30 March 2007 at 4:01 AM
of course in this case, you have to make background color pure white and if this pure white appears elsewhere in the image, it will become transparent too...
You might as well choose another shade as background, depending on the subject (bright values), black could be more convenient.
The idea remains the same: via the filter, eliminate all values BUT the one used by the background.
(hope it makes sense.. :) )
HindSightStudios posted Sat, 31 March 2007 at 8:42 PM
Polax, your so kind to post the graphics and try to help. Unfortunatley, I'm still doing something wrong, but I'll keep trying and searching until I get it.
All I want to do is import a series of PNGs into Vue, with the background keyed out.
Thanks again.