enter image description hereI'm a little new to blender so I need help.

I need to cut this mesh/solid stl file for 3d printing, but I don't know how to do it in blender. How would I go about cutting up a mesh into separate solid meshes? I've tried using the bisect tool and I was able to figure out how to cut a slice I wanted in the mesh, but I can't figure out how to make them two separate solid objects. Can someone help me?


  • $\begingroup$ Can you add screenshots/a .blend file? $\endgroup$
    – Shady Puck
    Commented Jun 25, 2016 at 17:15
  • $\begingroup$ Autodesk Meshmixer is made for prepping 3d prints meshmixer.com It's got a tool called 'cut' with an option 'slice' where both segments can be left over. $\endgroup$ Commented Jun 25, 2016 at 18:18
  • $\begingroup$ storm trooper dab $\endgroup$
    – eromod
    Commented Jun 26, 2016 at 1:40

2 Answers 2



  • Select the part you want to separate and press P Separate > Selection
  • Or press P Separate > By Loose Parts parts to break whole the object into all independent parts

You can quickly select all linked geometry inside the same object by selecting Faces/Edges/Vertex and then pressing Ctrl + L, or by hovering the cursor over some peace of geometry and pressing L

  • $\begingroup$ Thanks!! Very helpful!! Although when I do this there's a gaping hole in both meshes where I cut. How would I fill this hole i.e. make both separations complete solids? $\endgroup$ Commented Jun 25, 2016 at 17:39
  • 1
    $\begingroup$ If you Alt select a vertex it should select the whole loop of the 'gapping hole' - once selected you can key Alt + F to fill the selection. You might also want to try K + Z to slice through the whole object instead of Bisect as it can be more predictable. $\endgroup$
    – Patdog
    Commented Jun 25, 2016 at 18:40
  • $\begingroup$ As Patdog suggested you can use the operator Loop Select to select the whole hole, then just press F to fill it, if you don't mind the NGons $\endgroup$ Commented Jun 25, 2016 at 23:42
  • $\begingroup$ Okay. I also have one more question. Now that I've cut my model up into pieces for printing, I need to figure out how to position the parts so the flat, cut sides are parallel with the ground. How would I go about doing this? I could just eyeball it using the rotate tool, but it most likely wouldn't be perfectly flat. Is there a way I could perhaps snap/magnetize the cut side of the piece to the top of a block (making it parallel to the ground) and then delete the block? $\endgroup$ Commented Jun 28, 2016 at 14:14
  • $\begingroup$ Yes, there is. Blender is not very suited for this type of "precision" CAD-like work though, so it is a bit of an involved process requiring a few different steps. You should probably post a new question for it, I'll be happy to address it if I catch it in the stream. $\endgroup$ Commented Jun 28, 2016 at 15:40

I think what you want is software like 123D Make from Autodesk. It is freeware designed specifically for slicing STL models into layers:


AFAIK, it also has options for exporting to 3D printers.

  • $\begingroup$ I do have that software actually, but 123d doesn't have as many design functions as blender. You can import models, but you can only edit them if they were designed in 123D, which my model wasn't. $\endgroup$ Commented Jun 28, 2016 at 14:02

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .