Rhino fails to compute area

I’ve got an issue with a Brep, rhino always fails to compute its area.
Both the command _Area and the rhinocommon function Rhino.Geometry.AreaMassProperties.Compute() are not working. If I convert the Brep to mesh there is no issue to get the area, so I think it must be a Rhino bug.
Any idea? (model attached)

BrepError.3dm (81.3 KB)

Something pretty odd about that surface - turn on control points. There is an extra row of control points, it is degree 1 but has a crease in it, and the creased part has been trimmed off…

If you Dup the border, run Untrim then DivideAlongCreases and re-trim the surface, Area works. How was the surface made?

Thanks for your help @Helvetosaur

This is how I made the surface:

A planar polyline curve is extruded on the plane’s normal vector. Then the resulting brep is trimmed by the curves intersecting with other breps. The brep I’ve shared is one of this polysurface’s face. (Every other faces are alright)

I get that the output is weird for some reason, but even like that don’t you think that rhino’s area calculation should be able to cope with this? After all the trimming curves are good enough to define the surface boundaries.

Well, if you dup the border and explode it, you get 5 curves instead of the expected 4… The 5th one is a very small segment on one corner ~.003 units long, which might also be messing things up… The surface appears to be folded over in that corner.

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ooh thanks @Helvetosaur, I didn’t see this! No Idea why it is there, I’ll investigate. Have a good day