Hello, I am creating a line with the curve tool straight edges and multiple points, and then I add a Curve node with "Convert to NURBS curve" selected. However, nothing happens with the smoothness of the curve. Is that a regular behaviour in the new Houdini version 19? I know I can use the curve edit mode to turn it into Bezier and smooth it out, but with the Convert node I can switch on and off the smoothness.

I don't think the convert sop has changed in 19. Does the curve have multiple points at each point, effectively making the nurbs curve a linear curve?

here is a screenshot of the simple setup [pasteboard.co]
Yes, it is a linear curve, or the file if it is easier.

petarpavlov
here is a screenshot of the simple setup [pasteboard.co]
Yes, it is a linear curve, or the file if it is easier.

The curve tool is generating a bezier curve, which has two control points for tangents on each vertex. They are just collapsed onto the breakpoint making it a linear curve. Converting to nurbs won't make it smooth because the curve is already a bezier curve and is being rendered as smooth as the control points define. Converting to polygon with low fidelity first, then to nurbs can remove the extra control points.

To make a linear curve directly, change the mode to polygon.

That solves it! Thank you for the help!

If your curve already has multiple points on the same position, you can also apply fuse (to remove them) and change the primitive type to polygon, but this is only another workaround.