Question

If you run the following code snippet:

 Manipulate[
   Graphics3D[
     {Cuboid[{{-1, -1, -1}, {1, 1, 1}}], Sphere[{5, 5, 5}, 1]}, 
      ViewPoint -> {1, 1, a}, AxesOrigin -> {0,0,0}
   ], 
   {a, 1, 100}
 ]

and move the viewpoint from (1,1,1) to (1,1,100) with the slider you will see that after a while the objects remain fixed in size.

Questions.

1. When I move the viewpoint further away from the scene I want the objects to become smaller. How should this be done in Mathematica?

( EDIT: )

2. What is the position of the ‘camera’ in relation to Viewpoint?

Answer 1

See ViewAngle. Under “More Information”, note that the default setting ViewAngle -> Automatic is effectively equivalent to ViewAngle -> All when you zoom far enough out.

You just need to add an explicit setting for ViewAngle:

Manipulate[
 Graphics3D[{Cuboid[{{-1, -1, -1}, {1, 1, 1}}], Sphere[{5, 5, 5}, 1]},
   ViewPoint -> {1, 1, a}, AxesOrigin -> {0, 0, 0}, 
  ViewAngle -> 35 Degree], {a, 1, 100}]