I am looking at exporting an Apex model as a .bdf so that it can be interrogated in Patran. The model session units are mm-kg-s-N
When i look at the export options from the .bdf option i get a number of options for the unit system but none that match the models session units.
The option that i can see are -
m-kg-s-N
cm-kg-s-cN
cm-kg-ms-10^4N
cm-kg-micros-10^10N
mm-kg-ms-kN
cm-g-s-dyn
cm-g-micros-10^7N
mm-g-s-microN
mm-g-ms-N
mm-t-s-N
in-slinch-s-lbf
ft-slug-s-lbf
mm-khyl-s-kgf
mm-kg-s-mN
cm-g-ms-daN
ft-lb-s-lbf
Also it says, if you chose the "Custom" units system, you must ensure that the unit system you have defined is consistent. However, no "Custom" button is present in the down selected box. Where is this "Custom" option?
Apex only lists the consistent unit sets for bdf output, so mm-kg-s-N isn't shown.
The message is not well worded - it should say "a" custom units system, meaning any units system you've set up yourself.
Setting up a custom units system is how you can get it to write out inconsistent units. Use the "Clone" function to create a new system from the mm-kg-s-N system. Here you can tag the new cloned system as "Consistent" even though it isn't; now it should appear in the bdf output list.
It is not recommended, but is possible to use a inconsistent unit for Nastran file export.
Right mouse button select your unit mm-kg-s-N in "options/application settings/units-Unit System, select clone, change consistency field to "consistent". Now you can use this "mm-kg-s-N_clone" unit for the Nastran export.
