Hi there,
I have a problem here we my application receives a triangulated, closed surface which encloses a volume. The resolution of this surface is high, i.e. there are > 100,000 triangles in it, and it can be concave. Here’s an example:
I now also have an unstructured grid which contains a similar amount of 3D cells. For each of these cells I would like to know if its centre is located inside or outside of the enclosed volume given by the triangulated surface.
Nope, you would need the volume you are refering to in your initial post:
a triangulated, closed surface which encloses a volume.
If you dont have it, then my advice may not be as useful as you would need to reconstruct it, and Delaunay3D do not work with concave surface, so not an option.
Ah, sorry. No, the triangulated surface encloses a real-world volume, i.e. it describes the boundaries of a real world object. What I meant with ‘encloses’ it is that the surface is closed, i.e. it doesn’t have any holes in it. Hope I use the correct language here.
That’s similar to something I have tried before. Will vtkStaticCellLocator test every cell for intersection, or will it use its ‘locator’ functionality first to only consider a tiny subset of the cells? Else it would take too long again.
The locator internally uses a binary tree so finding the cell is O(log(n)).
It is fairly fast and is made for this specific usage.
You can however further optimize if you know that you may hit multiple times the same cells by caching the last N cells or even try to find in the neighbours before using the locator if you know the there is some spatial proximity when you iterate over your volume cell centers.
