Picked up an ender v3 se. Getting used to cura program. I've found a few chastity cages online but what is the easiest way to edit like the base ring diameter? Which program would you recommend to a beginner to design a cage or at least remix an existing design?
I highly suggest learning Blender, it's free, powerful and quick to learn. Here are some suggested add-ons for Blender If you haven't modelled before, it is a learning curve but it can be very rewarding! Happy modelling!
It's difficult (though possible) to make changes to STL (3d object) files directly. Much easier to edit if you have the original file or a step file, etc. As for learning to design, a lot of people like Tinker Cad, Free Cad, Fusion 360, OnShape, and OpenScad. I personally decided to use Onshape, but that's just me and all of them are fine. I also ended up finding the perfect cage (for me) that was designed in OpenScad, which made it real easy to dial in the length, diameter, ring size, etc.