Help: move camera origin away from middle of screen

Hello all,

I’m attempting to render my camera to only a portion of the screen. What I mean is this – normally in a game the UI just covers up part of the actual 3d game world on the 2d screen. This is fine in most cases, but in an extreme case (which mine isn’t), you would end up with the UI covering the middle of the screen (i.e. Diablo 3 when you open your inventory – your character is still in the middle of the screen, you just can’t see what’s on the right side). I’m aiming to have 3d world on the left, 2d menu on the right.

My current way of avoiding this issue is to have my menu on the far right, say about 300px, and the rest of the screen is covered by a raw image, with a render texture fed from the main camera. It works sort-of, I guess, except I get a warning stamp “display 1 - no cameras rendering” (but my game plays just fine). warning stamps aside, this doesn’t feel like an actual solution to the problem, feels more like a duck-tape fix.

Does anyone know of a way to address this properly? Many thanks in advance!
-theagemaway

p.s.
See attached image for clarity.

Render to texture and suffer from there.