Rendering the Enforcer - ZBrush Creature Design: Creating Dynamic Concept Imagery for Film and Games - page 692

After the render is complete, do not change the view of the Enforcer—not only will you lose the render
you worked so hard at creating, but it will take just as long to create a new render. However, if you don't
change the view, ZBrush stores the ambient occlusion and other render information in a buffer. This means
that if you need to redo the render, it should not take as much time, as long as you don't change the view of
the scene! This is a great time saver if you need to adjust the lighting or change a material property.
Once the render is complete, you are still not finished. In the next section, you will use the Render Filters
to add postproduction effects to the render. This will help separate the Enforcer from the background as well
as allow you to adjust the look of the image in real time.