How to draw CeTZ arc in x-z-plane?

Questions
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1

Hey, this probably has some very obvious solution that for some reason I can‘t seem to find. Is there a way to draw an arc in CeTZ, that’s on the x-z-plane. When i try arc-through and feed it points in that plane, i get an error. Thank you for your help!

2

Hi!

Please provide a minimal code snippet of what you tried to do, so we can further investigate the error.

Thanks. :slight_smile:

3

Sorry it took me so long to get back to you - here‘s the code I tried:


#cetz.canvas(
  {import cetz.draw: *

      // drawing reference axes
      line((0, 0, 0), (0, 3, 0), name: "axisY", stroke: (paint: black, thickness: .7pt, dash: "dashed", cap: "round"))
      line((0, 0, 0), (0, 0, 3), name: "axisZ", stroke: (paint: black, thickness: .7pt, dash: "dashed", cap: "round"))
      line((0, 0, 0), (3, 0, 0), name: "axisX", stroke: (paint: black, thickness: .7pt, dash: "dashed", cap: "round"))

      //labeling axes
      content("axisZ.end", [$z$], anchor: "east", padding: .1)
      content("axisY.end", [$y$], anchor: "east", padding: .1)
      content("axisX.end", [$x$], anchor: "west", padding: .1)

      //drawing arc between z and x axis
      arc-through((0, 0, 2), (calc.sqrt(2), 0, calc. sqrt(2)), (2, 0, 0))
})
4

The function arc-through() does not seem to directly support drawing with three-dimensional coordinates. The example here only uses xy-coordinates but the documentation does not directly state that the function can not have non-zero z-coordinates.

Since you want to draw the arc in the xz-plane, you can use the projection function on-xz. This will “promote” your arc points from 2D to 3D according to (x, y) → (x, 0, y).

// drawing arc between z and x axis
on-xz(arc-through((0, 2), (calc.sqrt(2), calc.sqrt(2)), (2, 0)))
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5

Thanks, that should work. On another note - would you happen to have such a handy solution for when I‘m trying to draw an arc outside any base plane?

6

Looking at the available projection functions, I think ortho() is what you would be looking for. In the example they use on-xz() to draw a rectangle in the xz-plane which is then “rotated” by the ortho() function.

2 Likes