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Hi Alan,

When using function Edit -> T3 Mesh -> Delete elements in polygone, BK deletes element but not nodes.


Open original.t3s and hole.i2s, use function Delete Elements in polygon, save output as hole.t3s
Display nodes in BK for hole.t3s
hole wireframe


Nodes hole



Expected result : Nodes are deleted too

"Delete Elements in Polygon" is deleting an element when it is entirely within a polygon... so I don't think this is a bug, per se. I think, rather, you're asking for one more option to "Delete Nodes in Polygon".

I'd be willing to add that new feature as it seems independently useful too.

Stay tuned... kindly... Alan

Hi all,

By design, the purpose of the function "Edit->T3 Mesh->Delete Elements in Polygon" is to cut holes or remove unwanted sections of a mesh. Both elements AND nodes should be removed.

So, the new behaviour can indeed be considered a bug.

Cheers... Martin

Hi,

The underlying code currently has 3 ways to delete elements:

1. if mode = 0, delete elements whose centres are inside of the constraint polygon
2. if mode = 1, delete element if all nodes are inside of the constraint polygon
3. if mode = 2, delete element if one node is inside of the constraint polygon

And "Edit -> T3 Mesh -> Delete Elements in Polygon" currently uses mode 1. This has been so for the last 10 years or more; unchanged by me.

I am planning to allow the person using this menu item to decide which mode they wish to use rather than the current hard coded approach of always using mode 1.

Kindly... Alan

The next BK installer after 9 October 2024 will contain this new feature.




Kindly... Alan

As specified by Martin, nodes not connected to another by an element should be deleted too.

In current BK, only elements are deleted but the nodes remain which is unwanted and a new behavior compared to stable BK (3.3.4 ?).

DoCullUnusedNodes() is being internally called before I made changes and still being called after the new feature I mention above.

Are you saying that unused nodes are not being removed?

Kindly... Alan

Exactly. Unused nodes are not removed.
See screenshot in original post.

Wireframe shows that elements are deleted but second screenshot shows that nodes are not removed.

If you open zip file, you will see 2 t3s. In both the node count is the same but not element count.

Ok... now I understand what you mean more clearly. Thanks for that...

I'll have a look tomorrow.

Kindly... Alan

The next installer after 10 October 2024 will have a fix.

It was an interesting bug! Thanks for reporting it. In fact, it had very little to do with culling unused nodes and more to do with the general code being used behind the scenes by the culling code.



Kindly... Alan