I'm not entirely certain what you mean, you of course have to change camera angle to paint on e.g. the back side of an object because it's not visible otherwise and so the Painted Shader has no idea that you want to put a stroke on front *and* back, nor how to make "two" strokes from one, so to speak (i.e. painting front and back simultaneously). But if you want to paint "in 3D" you need to switch to 3D mode on the Transform tab.
- Oshyan