I haven't found anything directly relating to this issue, but I'm new here; I apologize if somehow I missed it.
My project is set to 1920 x 1080. Fine.
I render a sub-clip with a bunch of effects from that project, also at 1920 x 1080.
The file is indeed that size, according to every possible way I can check.
I import the clip I just rendered back into the project, and ... it's not 1920 x 1080. I have the annoying Black Bars of Failure all around it.
I don't want to zoom in to fix it, I want to not have to fix it at all. Why is a file that has literally just been rendered by the program not matching up with the project size? What am I missing here?
If I'm understanding your problem ... Make sure your render template is the same as your project properties. Vegas can render in a different format than the timeline. For example your footage is 1080p and you want to make a Standard Def DVD. You can render the 1080p timeline to 480p. If you want the same format as your timeline, make sure you have the correct render template or you can create a custom template to match.