I am trying to replicate in Houdini what is called a tracer object in Cinema 4D, to animate what is called a sweep nurb in C4D. For some reason, I cannot get the ends to close, even though I selected “skin with autoclosure” in the sweep box. I am attaching the file. I tried a great many ways of animating the curve, and this works (with the exception of closing the ends). What am I doing wrong? Thanks. I can add a polycap and fix this, but why isn't the autoclosure working itself? Also, why does the animation at the end stutter during playback?

The help card says that feature only works if the path is closed. Which sounds kind of strange because if the curve is closed there are no open ends to being with..?

There is another thread which has an example file on how to add a taper sculpt to a line via a ramp parameter. It uses polyline for skinning instead of sweep.
https://www.sidefx.com/forum/topic/49955/ [www.sidefx.com]

I will look at the thread you mentioned using a polyline for skinning. It is easy to add a ramp parameter to the animated curve (see attached), but it still jerks around on the ends when animating. I have attached a similar file from Cinema 4D that was a whole lot easier to create, and allows bezier curves along the ramp equivalent (and there is no jerking). If any one knows how to stop the strange motion at the endpoint, I would appreciate it. (attachments: Houdini file with ramp and animated curve, C4D file with equivalent - requiring studio version).

Edit: solved in technical discussion forum by helpful member. I specified distance between points on curve, so as curve changed length, number of points changed. Solution was to resample based on number of points, not distance.

Did you ever find a solution to this?

I too have a sweep that needs closed ends.

Hi,
bypassing “polyspline1” solves the problem for me.

hello. i have same issue. i can't find out what you mean with “bypassing polyspline1”.

Make group of the two end profiles and fuse. Your looking at a post that was using the previous sweep node. New one in H18.
https://www.sidefx.com/tutorials/sweep/ [www.sidefx.com]