This brief tutorial will show how to use the Lower Thirds with Vegas Video
as though the thirds had embedded alpha channels. We used Version 5, so if you
have a later version some of the options or terminology may have changed, but
the concept will remain the same.
Firstly put your footage on one track and your lower third directly beneath it. See example below

If you play a preview all you'll see is the lower third with black since it's higher up on Vegas' timeline. We're going to tell Vegas to remove any black out of the third revealing the footage under it by using the compositing mode tool on the Lower Third. This will create a nice blend. So left click it and a drop down of options with appear.

Select Lighten - see below.

And that's it! Any areas in the third which are black will now be transparent.

If you'd prefer a solid Lower Third please check our other support pages. As always - experimentation is key to getting your desired result.