How do I use the cubitids option when exporting mesh?

How do I use the cubitids option when I export mesh to an analysis file?

The answer to your question actually requires a little background in Trelis. Trelis stores every element type starting at ID 1. Hence, if you have multiple element types in your model you can have hex 1, tet 1, and quad 1. If you want to export using the cubitids you must manually renumber the overlapping elements and put them into separate numeric groups. Hexes start at ID 1, tets start at ID 10000, quads start at ID 50000. One way to do this to create a sequential numbering scheme would be to do something like the following:

brick x 10
mesh vol 1
block 1 volume 1
block 2 surface 1
block 2 element type shell
renumber face in surface 1 start_id {Id(“hex”)+1}
export abaqus ‘myfile.inp’ cubitids

The APREPRO statement in the last line will return the ID of the last hex that was created and start renumbering quads/faces at the id+1 value. Actually, this is the kind of thing that Trelis does automatically if you don’t specify cubitids. If you want to use a predefined value just replace the statement {Id(“hex”)+1} with the fixed value.

The renumber command in the GUI is found under Mesh/Surface/Renumber or Mesh/Quad/Renumber and remember that you can enter APREPRO syntax in any input field in the GUI.

The advantage of using cubitids is that you guarantee that element 10000 will have the same number in Trelis as it does in your analysis deck and post-processor. If you need to track down a problem, it may be easier with fixed ID numbers instead of numbers that are just sequentially defined at export.

– Karl

Using the “cubitids” option will retain the Trelis node and element IDs in the mesh file. If more than one element shares the same ID in Trelis, the mesh export will fail and you will need to fix the model before exporting Trelis IDs. This can be done with the renumber command and incrementing the start_id.

The attached journal file will renumber the mesh entities types in sequential order and allows you to then use the “cubitids” option.
renumber_mesh_elements_all.jou (1.93 KB)