Concave Edges being reported as Convex, isParamReversed=False?

[amitabhVA4SD]

Hello All,

I am noticing a weird issue on one of the Part(s) in Inventor 2020.3.4

All the concave Edges are reported as Convex and the isParamReversed Property on all the reported Convex Edges is False? The Part file is attached to the thread.

Does the API have any limitations?

Inventor API Team and Experts please help

@MjDeck @JelteDeJong @johnsonshiue @michael.navara @WCrihfield 

Thanks,

Amitabh Mukherjee

[WCrihfield]

Interesting observation.  I'm using Inventor 2022.1.1 and still seeing the same thing.  If I extrude cut a rectangular hole through the ring, I then get a couple of edges in the 'ConcaveEdges' list, and they a all say False too under the IsParamReversed property.  I could not find a proper definition of how/why they consider one edge concave and another convex.  But it seems to me, after a little playing around with it, that all round edges are seen as convex, but some straight edges (not all) are seen as concave.  Because the way I cut out the ring with a rectangle, left 14 new edges, all of which were straight, but the list in VBA only showed 2 concave edges in the result.

Edit:  When I cut a small rectangular hole down through the ring (the same direction as the small holes), without cutting through the inner or outer edge of the ring, I then get 4 concave edges.  That means that only the 4 edges inside of the rectangular cut-out (in its depth) are being counted as concave.  The 4 edges on the top, and the 4 edges on the bottom face of the ring made by that little cutout, are not counted as concave.  And when I cut just the tip of a triangle our of the edge of the ring, I get one concave edge (the one on the interior depth of the cut), so the two vertical edges at the edge of the ring were not counted as concave.

[amitabhVA4SD]

Can you please upload the edited part file @WCrihfield ?

I think it is better to make use of pure maths to compute the Concave/Convex face by projecting a point from the edge circumference in case of circular edges and checking if it is contained in the SurfaceBody.

Thanks,

Amitabh Mukherjee

[WCrihfield]

Sorry about the delay.  I left right after my last post here so I didn't see your request until this morning.  I have attached the model this time.  It still has the rectangular cutout in it.  It also has the simple VBA macro I was using in its Document Project, named "InspectBody".  It simply used the Pick function to get the body, then a MsgBox to report the ConcaveEdges.Count & ConvexEdges.Count.

All I really did was download your model, create a sketch on the top face of the ring with simple geometry (circle or rectangle) to extrude/cut through the ring.  First tests were with circle cuts, but they did not result in any concave edges.  Next tried rectangular cuts.  Then started getting concave edges.  It seems like any edges on the interior of an extrude cut, within the depth of the cut (not new top surface or bottom surface edges) are considered concave.  A circular cut that goes all the way though, does not have any such edges along its interior depth, so they don't create any concave edges.  A circular cut that only goes part way though though has one concave edge (the circle at the bottom/inside of the extrude cut).

I hope this helps in some way.