Cura LE "merge models" question

Say I want to make a thing that consists of two parts that I want sliced at different infill densities. If I model them correctly so when using Cura’s merge model interface their origins place them where I want them upon merge, slice one at X% and one at Y%, and then merge them, does Cura respect the original infill numbers per model, or does it reslice to the last setting used? I am seeing more slicing happen upon merge, even if I slice a model, lock it, and then slice the other and lock it. But this may just be redoing the wall calculations, since the two models would share two walls that should go away upon merge.

I can and will do this as a small experiment, but thought I’d ask here if there’s a BKM for doing what I am trying to do. Should this work?


So I created a small set of cubes that assemble into one thing. Sliced the center piece with 80% infill, locked the model. Sliced the rest with 20% infill, locked that. Merged them, and saw some more “slicing” dialog in the GUI. Printed the result, and stopped it at 80% completion so the infill wouldn’t get capped. There’s no visible difference between the stuff that I’d hoped would be 80% infill and the other–it all looks like 20% infil to me.


Next experiment, I actually clued in and used the “per model settings” option, and got what I had hoped for: 80% infill in the center, 20% on the outside. My goal/folly is that I’m printing a large support for a plastic drawer to level it on a car seat. The drawer has holes on each side through which I could fasten the drawer and support together. Want to sink a 2mm knurled brass insert into a 3.2mm hole in the right spot on the support. 20% infill around that hole won’t suffice, and I hate to use enough plastic to print the whole support at 80% (or higher). I could do gradual infill (which I have finally figured out), but the contact point for the fastener is recessed a fair way from the top of the model…again, a lot of plastic where it’s not needed.

So I can split the design into two models, set their infill separately pre-print, and it should all be good. Because the bottom slopes, getting the respective origins right may be exciting. But it’s just math in OpenSCAD…it’s doable.

Sound like what you need is tree supports; that’s available in Cura. Custom supports may also work for you.