Run this snippet and then hit the space key. If this is the effect you’re referring to, it is due to the cameras perspective projection. You could create a orthographic camera projection and mask the object to that camera.
sync on
sync rate 60
backdrop on
color backdrop 0
autocam off
position camera 0, 0, 0
make object plain 1, 96, 24, 1
position object 1, -100, 75, 200
lock object on 1
make object sphere 2, 5
ink 0xffff0000, 0
do
line 24, 34, 24, 160
if (spacekey())
yrotFlag = 1
endif
if (yrotFlag)
yrotate object 1, wrapvalue(object angle y(1)+1)
endif
sync
loop
