Ray-tracing of Unstructured Meshes for Material Fractions

[erelson]

As a precursor to running ALARA in the unstructured mesh workflow, the material fractions of each tetrahedron are needed.

Currently:

• mmGridGen/mmgrid.py do this ray-tracing for structured meshes
• Ray-tracing on unstructured meshes is done by DAGMC.

Am I correct that uniformly sampling a tet with rays is an open research question? Maybe something for an NE506 project? But might also need to be done sooner than that...

Derived from #3.

[elliottbiondo]

Shouldn't every tet only have 1 material?

[erelson]

That requires a conformal mesh, which isn't necessarily guaranteed (e.g. cylinders), especially if the geometry is originally an MCNP model, rather than a meshed CAD model. Or such is my understanding.

[gonuke]

We can delay this by assuming conformal mesh to begin.

[erelson]

Using the conformal mesh assumption, the material at each voxel's center point is determined and tagged to the mesh.

Relevant commit: d2e306a