FreeCAD: Part: Slice

[last updated: 2023-05-28]
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FC Command and Operation notes

(link to:) FreeCAD Part_Slice
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In process ...
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• Introduction:
  • There surely are many uses for this procedure, most of which I know nothing about.
    My need for it was because I was building a model to be 3d printed,
    but it was awkward at the least to print it in one piece,
    so I wanted to build the model as a whole, and slice it to create separate printable parts.

  • The main procedure is:
    Part WB --> Part --> Split
    Here you have two options:
    • Slice apart:
      • creates a 'Slice' parametric feature
      • sliced pieces are put into a compound
      • explodes the compound into separate objects
      • "Slice apart" will not update the number of objects as the number of pieces changes.
        (no clue about the consequences of this...)
    • Slice to compound:
      • creates a 'Slice' parametric feature
      • sliced pieces are put into a compound
      • DOES NOT explode the compound into separate objects

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• Example:
  • Create a drawing to be sliced:
    PartDesign WB,
    create a model that has two features in the same Body,
        perhaps two pads from two different sketches
  • Create slicing plane:
    • with Part:
      • Part WB --> Part --> Create primitives
        with Plane selected, click Create, then Close
      • See that 'Plane' has been added to model tree
        This will be the slicing plane to separate your model into two parts
      • edit slicing plane size and orientation:
        • be sure it is big enough to slice the entire model:
          Select Plane in model tree
          in Data view, Property column, scroll to Plane
          adjust Length and Width as needed
              (double-click Plane heading in Property column if L & W are not visible)
        • orient the plane to where you want to slice:
          Select Plane in model tree
          in Data view, Property column, scroll to Base
          adjust Placement - Angle as desired
          adjust Placement - Axis of rotation as desired
          adjust Placement - Position as desired

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    • Or with Datum Plane:
      • This is slightly easier IMO, because you don't need to set the size of the plane.
      • PartDesign WB --> PartDesign --> Create datum
      • adjust properties to align as desired

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  • Create the slice:
    • Documentation on detailed procedure is sketchy.
      If you just do Part --> Split --> slice apart,
      an error comes up saying:
      "Select at least two objects. The first one is the object to be sliced,
      the rest are objects to slice with."
    • Select at least two objects:
      in model tree, click to select the last feature in your model. (JWID)
      Hold ctrl and select a second object (the slicing plane)
    • Part --> Split --> slice apart
      notice new entity in tree: Exploded Slice
    • If you expand the exploded slice entity,
      you'll see it's composed of Slice.0 and Slice.1
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    • However:
      • If your model contains more than one body, you have to join them first
        For example, if you've done a Revolve or other Part operation
        than creates a new entity in the tree
        that is not part of your original body,
      • Select main body, press-hold Ctrl, select second body/entity
      • Join them:
        • As always, there are several ways to do this
        • JWID:
          With both bodies selected as above,
          Part WB --> Part --> Boolean --> Union
          This will create a new entity in the tree: Fusion
      • Slice them as above, choosing the Fusion entity, then your slicing plane
        (it did not seem to matter that the plane was already inside the Fusion body...)

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  • Create a mesh for printing:
    • You can now create meshes for each slice,
      and separately export stl's to print each slice independently.
    • MeshDesign WB
      select desired slice in tree
      Meshes --> create mesh from shape
      notice new mesh entity is created in tree
    • export mesh as usual for printing.

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