Archived issue #0025042

Cone Meshing: Missing two connecting edges.

CommunityOCCT:Meshclosed14 public notes

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Description

BRepMesh_IncrementalMesh will generated invalid mesh. The result is shown in the attached image file Attachment 3 (PNG).

Steps to reproduce

1. Create a cone solid.
BRepPrimAPI_MakeCone aMakeCone(200, 0, 500);

2. Clean Mesh.
BRepTools::Clean(aMakeCone.Shape());

3. Generate incremental mesh:
BRepMesh_IncrementalMesh aMeshAlgo(aMakeCone.Shape(), 0.2, Standard_True, 0.2, Standard_True);

4. Display mesh with MeshVS.

Public activity

14 archived notes

Participants are labeled by their role within this record.

01Commenter 2
Dear Participant,

I can not reproduce reported problem neither on OCCT 6.7.1 nor on current master using Draw (see attached screenshot Attachment 4 (PNG)).

Please provide resulting shape containing broken mesh as well as description of the way how you display it.

02Author
Dear OAN,

Please have a try with following case, the bug is still there.

BRepPrimAPI_MakeCone aMakeCone(150, 0, 500);
BRepMesh_IncrementalMesh aMeshAlgo(aMakeCone.Shape(), 0.2, Standard_True, 0.2, Standard_True);

See picture Attachment 1 (PNG).
03Author
Dear OAN,

I don't have permission to assign this to the developer, please help me do it.
04Commenter 2
Hi Participant,

to whom you expect to assign this issue?
05Author
Hi OAN,

Please have a look at the bug again, it can be reproduced with new data input in my previous feedback.
06Commenter 2
Dear Participant,

Yes, I see the point - I have just tried to reproduce the bug using current master branch. In fact, mesh is consistent, tricheck command says nothing that means mesh is connected and does not contain lacks. Looking more precisely you can see that reported problem represents case with degenerative triangle (see the attached screenshot Attachment 5 (PNG)).

Such thing is possible due to transformations introduced during passing from parametric space to 3D (screenshot Attachment 2 (PNG) describes this process).

Nevertheless, such result is not quite fine for cone and it will be fixed in order of priority. Be sure we are tracking this issue and it will not be lost.

You also welcome to make your contribution to OCCT and participate in the development of the fix for this bug. We will be glad to see you as a community developer.

With [signature removed]
Oleg.
07Author
Dear Oleg,

I understand the problem and there is actually a degenerated triangle. So the generated triangulation is consistent. To keep this issue for further bug fix, you might be the best candidate for this issue.

Thank you,
Vico
08Commenter 2
Should be fixed in context of #28379.
Could you please check and create test case.
09Commenter 3
Branch [archived branch] has been created by Participant.

[revision removed]


Detailed log of new commits:

Author: nbv
Date: Thu Nov 8 09:57:17 2018 +0300

    0025042: Cone Meshing: Missing two connecting edges.
    
    Adding test case for the issue.
    The problem has been fixed by the patch #28379.
10Commenter 10
11Commenter 11
Reviewed.
12Commenter 1
Adding test case
13Commenter 3
Branch [archived branch] has been updated forcibly by Commenter 2.

[revision removed]
14Commenter 3
Branch [archived branch] has been deleted by Participant.

[revision removed]

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