Gimbal Lock for Phantom Pro 3 with PolarPro filters attached

I liked essamy's lens cap and gimbal stabilizer for DJI Phantom Pro 3
http://www.thingiverse.com/thing:1179071
but when I got some PolarPro filters, it no longer fit due to their larger OD. I recreated the cap from scratch using Onshape. An improvement I made is that I put a small lip around the inside of the lens cap so that there will always be a gap between the glass and the plastic cap. This eliminates the need for any sort of soft material to protect the filter.

The source file is