Composite expanded element numbers

How can we identify which expanded composite layer elements in the output correspond to each element in the input?

I’d hoped the .12d file would provide this information but it doesn’t.

One way I can think of is to read both `all.msh` and the `frd` file.
For each (2D) element in `all.msh` create a local coordinate system that has its origin in one of the corners of the element and has the Z-axis normal to the element. Then transform the nodes in the `frd` file to that local coordinate system, and check for nodes where the transformed XY coordinates match those of the corners of the original elements. From those nodes you should be able to find the 3D elements.

This is one of the reasons why I tend to skip shell elements and construct models for composites using C3D20R elements directly.

@rsmith. Thanks for the idea. I considered that kind of geometric search as well as replicating logic used in CCX. Both ways have a lot of complexity and it’s hard to know if you’ve covered all the edge cases. For example: offset, normals being averaged with adjacent elements, coincident elements, gaps in element numbering, where other expanded elements are, etc.

Not a definite solution but if you just want to solve one punctual problem one could assign a non-used property like temperature in a incremental value. Let’s say you assign T=1ºC to the first element, T=2ºC to the second. …
That value could be tracked later and recover the element number.

@Disla, ah the ever-abusable temperature Good idea but I’m looking for a general solution.

Another option might be to modify `ccx` to explicity output the mapping from shell to solid elements.

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