liderbug

Google has been no help, so ... Think a large building with concrete support pillers. I'd like to (example) construct an inverter "L" or a "7". A cube, 10,10,40 with another cube 10,30,10 off the top. I can do infill at 100%, but... What I'd like to do is insert a smaller infill version inside, say 4,4,35 + 4,8,4 at 100% and 50% for the rest. I did find a Youtube where I can switch from 50% to 100% at a given slice - which means my build just snaps at given slice. Or I guess I could drill size 4 holes and insert a size 4 wooden dowel mit glue. Suggestions please. Thanks