Part of a series on mesh intersection code improvements. Other Mesh Intersection Milestones…
this week’s Rhino 7 WIP contains:
- a completely rewritten
- a new
This is fully new code, so it is on by default, but you can choose to switch back to the old code.
The new intersector is designed to be more tolerant of overlapping mesh areas, as well as more tolerant of adjacent edges and superimposed vertices.
The new code takes a different approach for large groups of intersections, and because of this, it can greatly enhance computation times for many objects. In this example, 3456 meshes with over 500’000 vertices are intersected. The new code takes a little less than 3 minutes to complete on my system. The old code, even if only fed just half the amount of meshes, did not finish in 10 minutes and I had to manually terminate the program. In addition, next week’s release will even improve this case, bringing it down to about 1 minute.
massive.zip (2.1 MB)
All this good news, but there’s a caveat: this new functionality is not entirely finished, and we decided to release it now because there are at least a few cases where we see these improved results.
Please let us know if you discover new bugs. We are aware of a few ourselves. In some cases, the code is even able to tell the the intersection it created was wrong. In these cases, it will print this:
An intersection computed a wrong result. The causing triangles are: _3dFace 112.20292663574219,-8.9776668548583984,-2.1148440837860107 112.0255126953125,-9.1104488372802734,-2.1148440837860107 112.056396484375,-9.1504192352294922,-2.110210657119751 _Enter _3dFace 112.14628150413222,-9.0820278911035253,-0.72244736380784214 112.05639961329504,-9.1503509181935208,-4.6081842704980511 111.96749762268365,-9.2201260610692586,-0.72244736380784214 _Enter Found 0 intersections using tolerance of 0.001000. Largest intersection computation gap was 0.000512.
In this case, you can isolate and send only the few triangles that caused corruption of the entire intersection (the second line is a macro that can be executed by you). This way, it will be easier for you to let us know and debug new cases even without your model. In general, the code progresses without interdependencies, so even if you encounter a small area that does not intersect correctly and that is not reported, it will be OK if you simply
_ExtractMeshFaces and send us the result.
for Robert McNeel & Associates