DRESP1 RTYPE=VOLUME: difference with Optistruct

[DANiFL]

Hi! I'm trying to run an optimization in Nastran, minimizing the volume of the model, but not the whole model. In Optistruct I did:

DESOBJ(MIN)=99999999
[...]
DRESP1,99999999,VOLUME,VOLUME,PSHELL,,,SUM,111
+,112,113 [...]

So the optimization only reduce the volume of elements: 111,112... without problems.

In Nastran the DRESP1 is different with RTYPE=VOLUME (the ATTA and ATTB are Blank and ATTI only can be SEID (superelement ID)).

Anybody knows how to optimize in Nastran reducing the volume of certain elements, not the whole model?

Thanks!