About faults cutting the entire domain

Dear Pylith team,

Following an example on the Cubit forum (Webcutting error with nonplanar surfaces - Meshing - Coreform LLC, second message from ‘admin 1’), I built a mesh of a normal fault where the box is not cut in two parts by the fault (see attached file). The fault only reaches the surface of the box but no other surface. I used this mesh in Pylith (to compute surface displacements with prescribed slip) and it works. I remember reading somewhere on the Pylith website that the box had to be cut entirely in two parts by the fault. So I was just wondering if I was missing something. Is there any particular reason why the box has to be entirely cut in two by the fault ? I am asking because I am planning to add other fault segments in my meshing that are quite close to each other and it would be easier if the faults do not need to cut entirely the domain.

Thanks in advance for you reply


You are correct. It is possible to create interior interface surfaces (faults) that do not cut through an entire volume. It does not work for all of the different ways you can modify the geometry. The Coreform support indicates using chop volume 2 with volume 1 and volume 2 tetmesh respect tri in surf 9 works. I have also used subtract volume {idVolFault} from volume {idVolDomain} without needing to use the “respect” command. I believe other methods for constructing the geometry (webcuts) do require the surfaces to cut through an entire volume for the volume mesh to respect the surface.

When you want surfaces to divide volumes so that you can assign different materials (i.e., elastic and viscoelastic bulk constitutive models) to different regions, then the surfaces dividing the materials needs to cut through the volume being divided.

ok, thank you very much for your quick reply! :slight_smile: