Wrong volume for mesh with zero thickness

Rhino Rhino for Windows
1

Hi there,

for meshes with 0 thickness rhino (and grasshopper) returns wrong values. Unifying normals and/or rebuilding the mesh didn’t work. Any chance to get the right values (in this case the volume should be 0)?

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image2316×732 102 KB

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image1920×960 87 KB

Wrong Volume.3dm (4.4 MB)