Circular holes not lining up in shaded view

Rhino Rhino for Windows
1

I am modeling a simple shape and am seeing a weird graphics glitch. In shaded or rendered mode, the edges of the mesh don’t line up with the surface edges, quite dramatically:

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image1103×925 180 KB

I have checked the tolerance settings – it is the default for millimeters small. The object is about 100mm on the long side.

I’ve tried exploding and rejoining the surfaces.

I’ve tried changing the render mesh settings – the mesh updates properly, but still with the offset:

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image1113×921 196 KB

The isocurves are also misaligned with the surface edges:

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image1155×917 91.7 KB

The render mesh is actually correct, while the edges are not! What is happening here? What caused it to happen? It’s not hard to recreate it, but is there a way to fix it short of starting over?

2

Hi,
Please post the model, someone will have a look…

3

Here is the file.

broken file.3dm (252.3 KB)

I was able to fix it by exploding the object, running rebuildEdges on the top and bottom surfaces, and deleting and re-lofting the walls of the holes. I am still curious why it happened in the first place, though!

4

I fixed the file by Exploding the polysurface, RebuildEdges, Join.
Rebuilding the Edges seemed to fix it.

My guess is something in this model’s tortured path to this state buggered the edge tolerances.

Can you report the file’s provenance?

5

I built it from scratch :expressionless:

There wasn’t anything particularly complex about the process. As I recall I started with a box, did some WireCuts for the internal holes, and then scaled the object nonproportionally with a combination of using ctrl-shift on some of the outside faces and scaling them in and out, and ctrl-shift selecting a face and clicking the gumball arrow to offset it a few millimeters. I then filleted the corners and chamfered the edges and moved on to some other parts that mate with the holes, and that’s when I noticed it was broken.

I assume the scaling is what broke it. It’s weird that the outside edges would scale correctly but the inner edges wouldn’t…