[size=14.6666669845581px]I need to calibrate the P3's camera to use Photomodeler software. This requires taking multiple shots of a calibration drawing at various angles (Landscape, Portrait Right, Portrait Left). The only way I can figure to do this is to keep the gimbal lock on so the gimbal does not move while I'm taking these shots. Of course the Gimbal Overload warning pops up.[size=14.6666669845581px]Will this cause damage or is the gimbal smart enough to sense it can't move so it stops trying?

I don't think that it's going to damage the gimbal. I have forgot my gimbal clamp a few times at nothing wrong did happen.

Perhaps I'm not fully understanding the specific calibration process in your case...but why not just turn the paper, rather than the aircraft?  I've calibrated other cameras with other software and found that easier than moving the tripod/camera/lighting.