Do we still need downsample_trace?

[micheles]

Now both ComplexFaultSurfaces and SimpleFaultSurfaces store the original edges, so we could use those instead of downsampling. If the original edges are not available, should be considered an error?

[g-weatherill]

Can you point to the PR that added the original edges to the surfaces? The downsampling was added because we float the ruptures across the mesh from the whole fault, and store the rupture surface geometry as a mesh for each ruptures. However, the rupture mesh will only cover part of the full fault trace, so purpose of the function is to remove the points in the trace that all lie within the same azimuth in order that the rupture surface can be treated as a set of equivalent planes without generating large numbers of small aligned planes, which would be computationally expensive and redundant for GC2.

[micheles]

The attribute .surface_nodes was added in #554