I am currently working on a reverse engineering workflow in Grasshopper for an X-joint.
So far, I have successfully reconstructed the main geometry, the Brace and the Chord. Both are already modeled as a closed Brep.
The problem I am facing now is the reconstruction of the weld seam geometry.
More specifically:
I am only focusing on the upper weld seam between brace and chord
the brace is slightly inclined, so the weld seam is not planar
I extracted and processed scan data of the weld area (mesh-based)
The first thing i wanted to try was isolating the welded area by extracting the intersecting curve between the Brace and the Chord and moving it in both directions to limit the area.
My main difficulties are:
Creating a clean surface from the mesh that accurately follows the weld seam (without excessive computation)
Extending this surface into a proper volume (weld geometry)
Combining this weld volume with the brace and chord into a single closed Brep
(Boolean operations often fail due to tangential contact or small gaps).
I need to end up with one single watertight solid (closed Brep) that includes:
brace
chord
weld seam
This model will later be used for structural analysis. Any advice or suggestions would be greatly appreciated.
ShrinkWrap works quite well in terms of capturing the outer geometry of the weld region from the mesh.
However, I am running into a limitation with this approach, because ShrinkWrap essentially generates a closed outer shell that follows the mesh, but it does not preserve or respect the original geometry of the brace and the chord (i.e. their exact cylinder surfaces and wall thickness).
For my use case, this is important because:
the brace and chord are already reconstructed as clean Breps
their geometry (including thickness) needs to remain unchanged for further structural analysis
the weld seam should connect to these solids without altering them
So my challenge is:
How can I use a ShrinkWrap-like approach (or any mesh-based reconstruction) to generate only the weld seam geometry, while still keeping the brace and chord geometry exact and unchanged?
In other words:
I want to reconstruct the weld seam from the mesh
but I do NOT want to replace or approximate the brace and chord with a wrapped mesh
instead, I need a clean transition between the weld seam and the existing Breps
Would you recommend:
trimming the ShrinkWrap result against the brace/chord Breps?
or extracting only a local region and rebuilding that part into a separate solid?
or is there a more robust workflow for combining mesh-derived geometry with exact Breps?
