Patch mantaining polyline edges

I need to create a patch from a 3d polyline maintaining the edges but the option “maintain edges” need a starting surface…why I can’t create the patch surface simply by maintaining the input polylines edges?

sometimes it might be tricky when the curves/lines shear out in all directions, what might help is using a higher resolution for your points.

if you post a file people can have a look in specific.

Hi, encephalon,
thank you for your message.
The question is very simple…I would like the patch for a closed 3d polyline to strictly maintain the edges…but it seems it’s possible only to approximate it.

Hi Roy - that is generally correct - if the polyline is not planar then there is no way to match it exactly with a single surface. Feel free to post an example.


Hi Pascal,
here is the example. 3D polyline with Patch command applied. The Edges are approximated and not precise.

Yep, that is expected - the surface cannot have perfectly straight bits.


why I can’t use the option “preserve edges” without selecting another surface?

Hello- please see Help (f1 key) on this tool.


depending on your tolerance you can make it fit. i just approximated your shape, so it might be slightly different in your model.

make 2 curves sticking out like so

sweep with options untrimmed miters

patch with the following settings (again yours might be slightly different)

Bildschirmfoto 2021-11-03 um 19.52.11

join and use the command ShowEdges, if there are no edges showing inside you have successfully created a watertight patch

but the edges are no more the originals… :grinning: