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I am trying to cut a mesh along a set of 20 planes.

Goal is to make this 3d printable without support and in a larger format than my printer volume. See screenshot for the 3d model and the intended cuts along the planes.

  • I tried the boolean modifier intersecting my model with each individual plane. While this works, it is cumbersome to do this for 20 different planes. Automating this procedure for all the planes would be a solution.
  • I tried bisect tool, but it cuts along an infinite plane in parts of my model that I don't want cut. Also this procedure needs to be repeated along all the other planes and the volume needs to be closed manually each time.
  • I probably need to repeat the above procedure a number of times (accurately!) in my prototype development.

Ideally, a tool that takes a mesh as input with a set of intended cut planes would resolve this. I could keep this set of planes then, adjust my model, and repeat the cutting step according to these planes.

Any suggestions within blender (or other software?) would be welcome.

Thanks!! T

screenshot of mesh and set of planes to cut this mesh

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    $\begingroup$ Hello :). Why not join all the planes into one Object? Then you can use Boolean with all at once. $\endgroup$
    – jachym michal
    Apr 9, 2020 at 10:22
  • $\begingroup$ that is a great idea. The boolean tool however doesn't keep all new objects when it cuts. It cuts away one of the two. When I use your suggestion, it works perfectly, except for the fact that in the end only a few of the pieces remain rather than all the pieces of the original mesh. Thanks for the answer though! $\endgroup$
    – tibi3000
    Apr 10, 2020 at 13:33
  • $\begingroup$ Update: @JachymMichal your suggestion is the solution! When I apply this to a simple mesh, it does exactly what you describe. When applied to my more complicated mesh, I seem to loose parts. This is likely due to errors in my mesh, so I will focus on resolving this first. $\endgroup$
    – tibi3000
    Apr 10, 2020 at 13:41
  • $\begingroup$ Glad to be of help :). Good luck with your project. $\endgroup$
    – jachym michal
    Apr 10, 2020 at 14:18

1 Answer 1

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Having done this for 3D printing before, I can admit it's an annoying problem. Admittedly, I did so through booleans, and that was a complicated process. Here is a workflow adapted to the bisect tool:

Bisect Tool Method

process for cutting a mesh

  1. Join the objects as one. This will be necessary in any method.
  2. Bisect while in edit mode. Check the fill box to fill in the mesh where you are cutting it.
  3. Separate the cut mesh.
  4. (Optional) The other side of the mesh needs to have its faces filled too. Unfortunately, the bisect tool doesn't provide for that. Depending on the geometry, this may be easy to do by just selecting the edge to fill and pressing F (or using the menu). Another solution would be to duplicate the mesh after the bisect operation, and delete opposing sides of the mesh on each duplicate (so each duplicate will keep its fill where it was bisected).

Boolean Method

This involves slicing with a boolean cube that has been flattened.

slicing with a boolean

  1. The objects will need to be joined as before. Add in a cube, flatten it, and replicate it with the array modifier, spacing it out as large as your bed is.
  2. Apply the boolean modifier.
  3. After this, it will of course be possible to separate the mesh into different objects for the different layers as before. Use L to select linked parts of the mesh and P to separate those mesh areas into a new mesh object.

In this situation, the boolean operator does require geometry with volume, so the accuracy of this method depends on how thin your cube is.

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  • $\begingroup$ Thanks! See my comment above that the boolean method indeed does the multiple cuts when you join all the cutting planes in one object. For my complex mesh, this process results in parts being 'lost', which is likely due to errors in my model. $\endgroup$
    – tibi3000
    Apr 10, 2020 at 13:45
  • $\begingroup$ If your object is not completely enclosed from the start, it will likely not print well, so you will likely want to fix that.Perhaps simplifying the mesh and merging by distance would help? @tibi3000 $\endgroup$
    – Denis G. Labrecque
    Apr 10, 2020 at 15:20

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