Generate a half circle?

What’s the easiest way to generate a solid half circle or slice of pie in Vuo?

Or — why is this parametric thing not working?

circle.vuo (2.05 KB)

Make Parametric Object wants to generate a surface whose 4 corners (so to speak) are defined by X Expression and Y Expression at the minimum and maximum U and V values.

In your composition, since neither X Expression nor Y Expression uses V, the surface lacks the second dimension. The Make Parameteric Object node generates points around the circumference of the circle — which you can see by attaching Get Mesh Values -> Make Points Object to see the positions in the object — but not a meaningful 3D object that can be rendered.

Attached is a working example. Like yours, it uses sin and cos of U to go around the circle. The difference is that, for each unique U, it uses V to generate a pair of points: one at the center of the circle, the other on the outside edge. That gives the object the extra dimension that it needs.

circle.vuo (3.36 KB)

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Thank you Jaymie !
Helpful stuff

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Great explanation, thank you so much, @jstrecker.  

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