Sometimes you don’t need a full CAD workflow to make modifications to a model, your slicer is capable of some truly amazing feats! Here’s a story about a time where I had a model that I loved that didn’t quite meet my requirements and a remix that also didn’t meet my requirements. The “only” solution was to mash up the two models to make something a bit more customized.

I’ve been trying to upgrade my domains of nerddom and one area I’ve always been mostly-blind to is the physical craft of electronics. I know just enough to be dangerous and spot obvious problems (after they’ve combusted), but I’ve never delved into the practice of soldering or building/repairing my own electronics. Luckily, I have friends well-versed in this domain. I bought a PINECIL and had a friend walk me through the very basics of soldering.

He recommended this PINECIL case on Printables, which is an extremely nice model. Functional and beautiful. The only issue with it is: I’m not gonna use those extra iron tips. While I have another tip, I have neither the experience nor knowledge to use them effectively yet. I’m still an absolute beginner at this stage, I just don’t know what I don’t know.

My friend recommended a flux pen for my beginner soldering kit, but the default case didn’t come with a spot for it. Luckily, this remix of the PINECIL case had a socket that fit perfectly, but it was mashed up with the soldering iron tip holder that I didn’t need. I wanted to blend the models together so I could replace the spare-tip holder with the flux pen socket. Normally, I’d just take this out to TinkerCAD, but I wanted to see if I could get away with a more “low-tech” solution.

For better or worse, that low-tech solution was some goblin engineering shit with PrusaSlicer:

A screenshot of PrusaSlicer showing two models overlaid on top of each other. The models are overlaid with several negative-volume modifier cubes. It looks like a chaotic mess.

A screenshot of the PrusaSlicer part detail window. This shows the original PINECIL case model with a couple negative volume boxes added. Under that, a model named “THIS_IS_FINE.JPG” has SIX negative volume boxes added.

What have I done??

Instead of solving this problem “correctly”, I decided to solve it “good enough”. PrusaSlicer has a great feature called “Negative Volume Modifiers”. You can do a lot of different functions with these simple shapes, even adding text to models easily. This particular modifier just removed areas of a model, kinda like a big boxy 3D eraser.

Let’s dive into what this mess actually does:

The first model uses negative volumes to remove the spare tip holders from the model. It isn’t perfect and leaves some gaps in the original filet of the case, but it’s good enough:

A screenshot of PrusaSlicer focusing on a single model with a couple negative volume boxes added. These negative volumes remove the spare soldering iron tip holders.

A screenshot of PrusaSlicer showing the sliced model after the negative volume boxes were added. The slicer preview shows the soldering iron tip holders are not printed. Instead a blank space is left behind.

This leaves us a space to add the flux pen socket!

The second model just removes the entire case around the flux pen socket, leaving just the socket behind:

A screenshot of PrusaSlicer showing the second sliced model after several negative volume boxes were added. The resultant print is just the flux pen holder without the case around it.

Now, we just gotta overlay those models just right and….

A screenshot of PrusaSlicer showing the print preview of the two models mashed up. The soldering iron tip holders of the original model have been replaced with the flux pen holder from the second model.

Voila! We’ve now mashed up both of these models to come up with a jankier third option. Slicing this model does result in some problematic g-code and PrusaSlicer isn’t too happy about it: