I've juste tried GrandMA on PC for Mac OS v 18.104.22.168 and in the 3D view I cannot see the "box" or the stage or the fixture's bodies.
Also the ambient and point settings do not do anything.
Could it be because my computer doesn't have a big graphics card? Or is there a setting I am not aware of?
I have a:
Macbook pro 13" retina 2013
Graphics: Intel Iris 1536 MB
16 Gig RAM
Mac OS 10.13.6