Rendering Alphas from PI

I am having several issues while rendering projects to movs with alphas. No matter if it is straight or premultiplyed, whenever I get my content on Vegas there are allways some undesired black dirt information on them. I am not sure if it is an issue related to PI or Vegas, but I only get that when exporting from PI to Vegas.
So far, the solution to this is to import the PI rendered file into Adobe Media Encoder and just convert it to another compatible codec with alpha. It gets me some delay on pipeline, but works perfectly.

Hi @pfelberg ,
You need to change how Vegas works with alpha channels to get “clean” particles. Click on the three horizontal bars at the far left of your track with your rendered particles. Select “Compositing Mode” and then select “Screen”. Depending on your particles one of the other blending modes may work better. I hope this helps!

I’ll give it a try, but usually every footage with alphas work perfectly with “source alpha”. I only have this issue while importing PI renderings.


I believe that Particle Illusion creates intense and non-intense alphas which don’t get displayed correctly using “source alpha”.