"I'm creating a Blueprint Actor using HISM in UEFN.
I placed walls using Copy to Points like in the image, but some parts are overlapping and the positions are not correct. Can I get advice on a better workflow or solution?

In outline:
Take your lines with the fused points - second image - into a sweep SOP.
In the sweep:
Surface shape: ribbon
Columns: 1
Under the construction tab, set the Up Vectors > Target Up Vector to 'Y Axis'.

Poly extrude SOP - set distance value.

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You may want to do some sweep geometry clean up with the Boolean / Divide / Dissolve Flat Edges SOP's before extruding, but that is fine tuning if you want very clean geo.

Mike_A
Thank you very much for the response, and I think I may have explained it incorrectly. In UEFN, I need an instance in order to create HISM instances.