Hello, could you check the logs of your project to see if the application crashed? If so could you send the logs to us?
The key factor is not just the number of elements in your scene but the volume taken by the elements you would like to process as well as the distance between the elements you would like to remove and the boundary of your volume. In your case you speak of structural framing that I assume are contained in walls and thus only a few centimeters/millimeters away from the boundary of your volume (wall exterior). You ll have to keep a small voxel size so that the algorithm can detect that there are voxels with “wall matter” between the boundary and voxels with “structural matter”.
So a big number of meshes with a small voxel size will take time: could you work per areas?
You could also try a small subset of walls to see what are the values for your use case.
Just in case, the documentation here is quite complete: https://docs.unrealengine.com/en-us/…owTo/Jacketing