Yes, currently the colour and transparency can only be set by the layer.

The visualisation has no function to hide edges individually. I don't see the point either, if I want to show edges, I want to show all edges - not just some. If the edges within the face are not desired, the faces probably have to be combined. OCCT also has algorithms for this (UnifySameDomain, if I remember correctly).

Yes, I think this is a good way to solve my problem. So I tried my best to get the right answer, but still I cannot get the right result.

After I add all faces to the compound, I tried the ShapeUpgrade_UnifySameDomain class, I think I already do everything I can, but still cannot get the right result.

At the end, I get a solid all the same.

What should I do? Help please.

Thanks

Did you try to play with the tolerances? Could be a precision issue.

I tried play with the tolerance with the code line 158~160, but it has no affects. I think the opencascade maybe has tolerance settings, I am searching for how to dealing with it.

Did you try to play with the tolerances? Could be a precision issue.

It is not only the precision issue. I made a mistake, every time I make a face from DxfPoint. So even if the two edges are the same, but the TopoDS_Vetex is not the same, as a result, the TopoDS_Edge is not same. So when I use ShapeUpgrade_UnifySameDomain to merge faces, I failed.
I changed the import method, let all faces have same TopoDS_Vertex and TopoDS_Edge, the ShapeUpgrade_UnifySameDomain get the right result.

Thanks and Regards,