GC's 3D viewer used to show models in perspective view mode, which is more realistic than the currently used parallel (or orthographic) view mode. Being able to switch between the two would be great.
Follow the below mentioned steps
Answered with a tutorial: https://grabcad.com/tutorials/is-there-any-chance-the-3d-viewer-will-get-perspective-view-mode-back
I hope, this will help you