Remove (3D)

[jgomez720]

Description

All extrudes should be able to remove material as well.

Functionality

• Have an option in Extrude to remove material. The default behaviour of extrude should be to add material, but the user should have an option to remove it.
• Shouldn't work if the user is trying to extrude in the opposite direction of correct model body.

Supporting Docs/Images

Extrusion Dialogue

Error message if user tries to remove in opposite direction of model body

Extrusion with (remove) selected

End Result

PseudoKCL

the |> extrude() function adds material by default, but will expect the parameter remove: true.

const box = startSketchOn('XY')
  |> startProfileAt([-9, 6], %)
  |> line([18, 0], %)
  |> line([0, -12], %)
  |> line([-18, 0], %)
  |> close(%)
  |> extrude(4, %)

const extrudeRemove = startSketchOn(ExtrusionStart(box))
  |> startProfileAt([-6, 3])
  |> line([12, 0], %)
  |> line([0, -6], %)
  |> line([-12, 0], %)
  |> extrude(1, remove: true, %)

Expected Result

[adamchalmers]

Why not just use a normal boolean operation?

const outer = startSketchOn('XY')
  |> startProfileAt([-9, 6], %)
  |> line([18, 0], %)
  |> line([0, -12], %)
  |> line([-18, 0], %)
  |> close(%)
  |> extrude(4, %)

const inner = startSketchOn('XY')
  |> startProfileAt([-6, 3])
  |> line([12, 0], %)
  |> line([0, -6], %)
  |> line([-12, 0], %)
  |> extrude(1, %)

const finalShape = outer.remove(inner)

[alteous]

Has this been implemented in the engine?

[adamchalmers]

No, not yet.

To answer my own question above: we shouldn't use general-purpose subtraction. Here's why.

Kurt and Josh pointed out that remove-extrude is a special case of more general 3D constructive geometry subtraction. The former is much easier than the latter (as we discussed in-person with Alyn, fully general 3D subtraction is, mathematically speaking, Fucking Hard). So we should probably prefer a dedicated remove-extrude operation because fully general 3D subtract will be a while away.

[jgomez720]

oh I think David was commenting because this discussion got closed by mistake. I reopened it