Hi,

I'm trying to obtain smooth curves from an imported spline mesh (a tractography dataset exported as FBX from Blender). What I've tried so far is the polyspline node to reduce the mesh from a ribbon of quads to a line of points. However the line is not as smooth in corners as the native curve primitive in Houdini. The screenshots below show a Houdini curve on the left, and the polyspline geometry on the right. When rendered with Arnold, the individual segments making up the polyspline become glaringly obvious.

Any tips on how to better smooth the polyspline?

Since you are able to work only with the naked curve, you can convert it to a NURBs curve or use the Refine or Resample SOP.

I don't know much about arnold. Perhaps it has a rendertime curve smoothing option? For Mantra, this is on the Geomtry tab – “Render Polygon Curves As Subdivision (Mantra)”.