Just a sketchy idea & not 100% sure if the results would be useable.
The problem is how to fix imported surface geometry, this idea is only to create a simplified copy to substitute in if required.
The sketchy idea:
Create a star of 8 line/axis
Stack these vertically (10mm apart?)
Place the star part in an assembly alongside the downloaded surface part.
Create a point where the surface intersects the surface (only the outer point)
Create an irregular hexagon connecting the points.
Loft the hexagons together.
Repeat in the Y & Z directions.
Create a solid from the intersections of the 3 lofts.
It’s an idea, not sure if it’s a good one, not impossible?
Regards
Andrew.
