Select all objects visible to camera / drag select

[apeiron]

Hello,
I have a huge and complex scene (basically an entire city)
after positioning the camera for the shot I'd like to render, It would help free resources and keep me work smoothly if I could delete everything that is not in the shot.

In any other 3d software I would simply drag select everything in the viewport and delete the rest.. but doesn't seem I can do that in Keyshot, is there any way?
there's way too much stuff to go through one by one on the scene tree, or ctrl clicking every object in the viewport.

thanks a lot!

[LayC42]

Have you ever tried to use a selection window (shift + holding LMB and drag a window inside the entire view port)?