To do it, set Radial Gravity (With W), make a box out of Wall, then place a Stickman. Use his dust for a nice foundation, then grab STNE and put a tiny amount on his head. Have him spray it around for a bit and add some Concrete or Broken Glass if you want. After that, turn on normal gravity then melt everything. Then turn on the Radial Gravity again, and you have a nice round planet