I wanted to test the print volume of my Mars, and liked the idea of having a tangible representation of it that I could hold in my hands. Particularly with the need to orient things in a certain way with resin printing, I like being able to compare the size of it to objects in the real world and even check for fit by putting an item inside the volume in whatever orientation I wanted.

I was not aware of any standard tests for this and wanted to familiarize myself with the capabilities and limitations of my new printer so I designed one myself. It has a few features to find the exact size of the envelope and demonstrate some of the capabilities of the printer (small features, thin walls, etc.). I made it almost completely open on two sides so it would be easy to fit objects inside. It prints flat on the plate and requires no supports.
Interestingly, I found the actual print volume to be a bit smaller than the 120x68x155mm advertised. I found the actual volume to be 117x65.5x151.5mm.

I designed this for my Mars print volume, so exact overall dimensions are 117x65.5x151.5mm. If your volume is different, it can be adjusted in the slicer to use on any resin printers with similar sized envelopes.

As mentioned, there are features on each side to tell you when you are pushing out of the bounds of the print envelope. Each face has at least a few pointed features. If they come to a point, everything was in the print volume. If the points of any of the features are blunted (or completely missing), then they are projecting out of the print volume. See included picture for reference. The features are .5mm tall, so if they are blunted you can can get within .5mm in X/Y/Z by visual inspection.

I can get into this is more detail... and I have some ideas for improvements if anyone else actually turns out to have interest in it.

I found at least one other volume test after creating this, but it required a lot more resin and part of this project was learning the limitations of the printer and designing around them for myself.

Hope someone else finds some value in this, and let me know if you have any feedback!