Hybrid elements in Coreform Cubit

Hi There,

I am looking to know if Coreform Cubit can generate hybrid meshes. See figure below.

I have a 3D model with internal planes (fault surfaces in geological language) that are difficult to mesh using Hex elements. I have tried other mesh software and was able to generate a hybrid mesh. Tetrahedral elements are placed near the faults planes and Hex elements away from it.

Let me know if this is possible with your capabilities.

Hello @jsilva.mit,

I know we talked about this during our phone call, but I’ll recap basic functionality for the sake of other forum members.

Coreform Cubit can generate hybrid meshes, but there isn’t a single command that sets a volume’s scheme to be “hex-dominant” or “hybrid”. Instead hybrid meshes are created “bottom-up”. For example:

# Create geometry
bri x 1
volume 1 copy move x 1
merge all

# Mesh the all-hex region(s)
vol 1 scheme map
mesh vol 1

# Mesh the tet-region(s) -- pyramids auto-inserted if needed for transition
vol 2 scheme tetmesh
mesh vol 2

Here’s the resulting mesh:

And here’s the transition layer of pyramids (draw pyramid all)

Here’s another example that is a bit similar to your first example, except that (as we discussed) I’ve applied a hex-mesh near the fault and a coarser tetmesh on the far-field:

single_fault.cub5 (849.4 KB)

open "C:/Path/To/single_fault.cub5"

Volume 1 copy 
thicken volume in surface 8 depth 0.125 both 
webcut volume 2  with sheet extended from surface 8  

subtract vol 3 from vol 2
graphics tolerance angle 5
remove surface 14  extend 

Surface 16 19 17 15 18  copy 
create surface curve 48 47 43 37  
create volume surface 25 26 23 22 21 24  noheal 

webcut Volume 3 tool Body 1 
delete Body 1 

# Merge far-field to each hex-region individually, leaving fault surface discontinuous
imprint all
merge volume 2 with volume 3
merge volume 2 with volume 4

volume 3 4 size 0.1
mesh volume 3 4

volume 2 scheme tetmesh
volume 2 size 0.4
mesh vol 2