If your wondering how to use a reference image as a background without your model intersecting your image I have been experimenting. Here is the trick. Import your image in Documents. Under Layer tab adjust the displace Z slider to about 800 (this setting worked for me) . Now when you load your tool (don’t forget to press edit) and try to rotate it it won’t intersect with your image. I hope this helps those who been frustrated like me, especially those who have been using Blender, 3DMax. :)