This is a quick tutorial on splitting a mesh in Blender with a guide plug.

  1. Start with your beautiful mesh. I’ve added Blender’s Suzanne mascot: monke

  2. The first thing we’re going to do is create a cutting mesh. This will determine the shape of the guide plug and shape of the cutting surface.

    First, create a mesh for the plug. Press Shift+A to add a mesh. I’ve chosen a cylinder, but you can use whatever mesh you want. A box-shaped plug will prevent the two halves from rotating and might be a better choice. add cylinder You can expand the menu in the bottom left to input the exact dimensions of the mesh: size cylinder

  3. Use the same process to add a cube that is large enough to encompass the portion of the mesh you’re cutting out. Use G+Z to grab the mesh and move it along the Z axis until it’s just barely overlapping the bottom of your plug mesh. Left-click to confirm your placement. Pressing Numpad 1 will put Blender into a front-view that may make positioning easier: base

  4. We’re now going to take the union of the plug+cube to make a single cutting mesh. To do this, select the cube, open the modifiers panel on the right (wrench icon), and search for a modifier: mod mod modify Search for a “Boolean” modifier. Change the modifier settings to “Union”, choose the plug mesh as the object target, and set the method to “float”: settings The modifier is currently editable and will react to the component meshes moving. We want them to be permanently attached. Finalize the modifier by clicking “Apply”. just do it

  5. You now have a cutting mesh named “Cube”. You can now delete the plug mesh - we won’t need it anymore. cleanup Go ahead and position your cutting mesh in the mesh you’re trying to split. You can use G to grab the mesh and R to rotate it. You can also press N to open the properties panel in the top right and input exact values for position/rotation. prep

  6. Make a copy of the mesh you’re trying to split in the top right panel. You can just select it and press Control+C and Control+V. getting out of hand

  7. Select one of the copies of your mesh and add a Boolean modifier to it like you did before. This time, set the modifier to “Intersect” and select your cutter mesh as the object target: cut 1 Go ahead and apply the modifier. Note that you can’t undo this action. Make sure you have a clean copy of your object file somewhere in case this goes horribly wrong.

  8. Select the other copy of your mesh and do the same thing, except setting the modifier to “Difference” this time. cut 2

  9. Congratulations! You’ve now cut your mesh apart: yippee You can now select+export+print these separately. I’ve rotated them a bit for clarity, but you don’t need to do that.