SubD pipe creates unwanted twists

With the Rhino WIP SubD multipipe command, is there currently any way to prevent the topology from twisting? Or is this something that is in the works?

image key: pink highlighting the unwanted “twists”, green highlighting the “untwisted” shapes.

This is filed as RH-59271 already to investigate different means to control this. Thanks for the post, I’ll add it to the report.


Hi @Sukey_Thomas,

As Brian says, this is an issue we are working to improve.
There is one minor modification you might be able to make to your model that I think will give a better result even with the current version though.
Where you have segments of your curve network which are nearly straight, but represented as NURBS curves, if you replace them with actual straight line segments, the pipes there will be much less prone to twisting.
This is because on even slightly curved segments, the tool orients the cross sections along the segment according to the curvature, whereas for straight segments it always tries to find the twist minimising matching between the 2 ends.

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Thanks! Will give it a try.