Hi Page,

The issues I was referring to are related to misuse of a connected triangular 
mesh. What you created is a “triangle soup” with no connectivity information.  
That is not the best way of specifying a collision mesh. You should read more 
carefully the description of a ChTriangleMeshConnected and generate all its 
information. But even better is to use a mesh specified in a Wavefront OBJ file 
and let Chrono read it and create the corresponding collision object.  There 
are only very few situations where one would need to create a trimesh 
programmatically. Not knowing what exactly your end goal is, other issues with 
the code you provided could be: using a trimesh when a convex hull would do 
(more efficient collision shape) and not sharing the geometry (assuming you 
have multiple objects/bodies with the same collision shapes.

--Radu

From: 'Page' via ProjectChrono <[email protected]>
Sent: Saturday, December 2, 2023 8:20 AM
To: ProjectChrono <[email protected]>
Subject: Re: [chrono] The collision is strange after using AddTriangleMesh


Hi,Radu

Thank you very much for your prompt reply. The issue you pointed out is 
correct: I made a mistake in the direction of the normal. When I corrected this 
issue, it seems to work properly. In this demo, I just tested using a 
triangular mesh for collisions, and in the future, I will use complex models 
for precise collisions



You mentioned that there are many issues with my code, can you help me point 
them out? Thank you very much. I am very interested in this physics engine



--Page

在2023年11月30日星期四 UTC+8 16:02:20<Radu Serban> 写道:
Page,

First of all, please attach code as a text file, not a Word document!

There are many issues with the code you provided and it’s not clear to me why 
you are trying such a low-level approach when other solutions are available. If 
you are convinced you need to create a ChTriangleMeshConnected programmatically 
(hopefully for something other than a box), please first make sure you 
understand well how those work and how they should be created.

Having said that, one problem with your code is that you define the mesh with 
normal pointing inwards. The order of the vertices in each triangle follows the 
right-hand rule.

--Radu

From: 'Page' via ProjectChrono <[email protected]>
Sent: Wednesday, November 29, 2023 10:03 AM
To: ProjectChrono <[email protected]>
Subject: [chrono] The collision is strange after using AddTriangleMesh


Hi,all

I write a simple demo, I built a ChBody, use AddTriangleMesh, add a cube mesh, 
so that two cubes do collision, but the collision effect is obviously wrong, I 
hope someone can help me, the following is the code and demonstration video
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