Non-manifold bug?

Is the Non-manifold error actually a bug? I have made this sketch (see below) but Shapr3D doesn’t extrude it because it gives the non-manifold error. It allows to extrude only the smaller parts.

As suggested in the forum I have drawn some extra lines to split the sketch and to identify the problematic area. After drawing the extra lines (splitting the sketch into smaller parts, the second picture) I was able to extrude the sketch in 7-8 separate parts. Therefore it seems that there was nothing to fix.

The non-manifold state of an extrusion does not seem to be a bug, in this case, just a property of solid body modeling. There may be some small detail in the sketch that would result in self-intersecting geometry or such a tiny detail that is quite close to the tolerance of Parasolid. If we would allow the extrusions to be open polysurfaces instead of solid bodies, you may not see the popup message but the models will not be watertight.
If you could share the workspace, we’d be happy to have a look at the possible causes.

Thanks for the comment. Yes, I could share the model if you mean that with workspace, see attachment.
2D_Vine.shapr (238.4 KB)

Thanks for sharing the workspace! In the video below you’ll see a loop that is one of the details that cause the non-manifold issue.

These loops have barely any thickness but they are perfectly enough to end up in a zero thickness issue along the corners if they are extruded together with neighboring elements. It can also happen that they are so thin they almost meet the tolerance of the modeling engine which is something that is better to avoid.

I am not sure how this sketch was made. These details are regularly a result of an import process where the conversion flow during the export makes mistakes like in this example. Please clean up all of these loops with the Trim tool and everything will be fine