if you are familiar with python I would recommend you to use the scripting environment of MSC Apex to create the Model. You could the switch to Patran to continue. However, execution of the script in Apex may take a lot of time as well... . Since Honeycomb Sandwiches are highly parametric, I do not see a way how to model these without scripting. Some CAD Software extensions might supply predefined parametric honeycomb patterns, but it is unlikely to find these tools in FEM Applications.