See Curves for more information on RenderMan curve and its attributes such as how to turn on round curves.
To render the curve, we need to add at least a width attribute, curve interpolation and basis.
Add Width Attribute
- Add a width attribute with Attribute Create. Set a width value at the bottom, e.g. 0.01.
- Map the width attribute to RenderMan attribute with Attribute Rename.
- Connect the nodes.
Add Curve Interpolation and Basis
In your ROP, select Edit Parameter Interface and add ri_curveinterpolation and ri_curvebasis. Set the interpolation and basis accordingly.