Depending on the effect you want to get, set
Bounding Box Type of the source's
Transform other than
No Bounds.
OBS Studio Help Guide:
https://obsproject.com/forum/resour...ware-studio-multiplatform-help-guide-pdf.365/
Problem is, if I use any of the other settings for the bounding box, I can't crop away the black borders that come with a 4:3 game being projected in fullscreen on a 16:9 monitor. Using any of the other settings for the bounding box squishes the entire 16:9 fullscreen into the box, black borders and all, and they even show up no matter how wide I drag the source. I should probably mention that I don't even know what these inner and outer bounds are, I'm just trying to experiment my way forward with the different settings.
Though it was a pain, with no bounds I could always crop the black borders and make the projected source fit nicely into the set borders on my customized backdrop. However, this process was way too infuriating as I had to roughly estimate the ratio by making educated guesses as to what the fullscreen game was going to look like. I had to resize the source for when it would show up as windowed, while at the same time take into account the estimated difference between what the source looked like as the game was in windowed mode as opposed to what the source looked like when the game was in fullscreen, thereby indirectly determining what the dimensions would be for a fullscreen game. An extremely convoluted process. It was also kind of unreliable as the dimensions would screw up once in a while for some unknown reason and I had to do it all over again.
It would be so nice if I could just resize the source in OBS as I want it, crop the borders, and then make OBS ignore fullscreen toggle for the source.