OK, voice of sanity here. Projection master doesn’t allow you to rotate the model because it is a still frame of your canvas. Going into this mode allows you to use the 2d paint tools to paint both colour and deformation. You cannot use your regular 3d brushes and you cannot move the model on your canvas either. The idea is to take advantage of the 2d painting tools to do things you can’t do with the 3d painting/sculpting tools. Once you click the projection master button again and click ‘pickup now’, Zbrush ‘projects’ all the details you painted onto the area you see and you go back into your regular 3d mode where you can continue sculpting and polypainting.
The resolution of your mesh, UV texture image and canvas will vary so the quality of your results after you press ‘pickup now’ will vary. So, it is best to keep your mesh, texture and canvas size at a high level so the quality of your painting translates properly.
Hope this clears things up.
Cheers,
Revanto 