This is a grid for helping positioning exposure test models for Anycubic's Resin Exposure Range Finder (RERF) feature. The dimensions are set for the Photon Mono 4 bed, and should fit any bed with same width and length.
Also throwing in the .SCAD file so you can adjust parameters for any bed size.
More on how RERF works:
The author marked this model as their own original creation. Imported from Thingiverse.