You can use the Nonlinear Roll Damping definition to model roll damping due to bilge vortex shedding or the effect of bilge keels in a time domain Hydrodynamic Response analysis. This doesn't require you to change the geometry in SpaceClaim. Here's how:
- add a Nonlinear Roll Damping object to your vessel: right on the vessel in the Outline tree, then Insert > Nonlinear Roll Damping
- in the Details panel, change the 'Nonlinear Roll Damping' option from 'Use a Coefficient' to 'Define Bilge Parameters'
- define each end of the central line of the vessel by manual definition, or by selecting vertices from the geometry
- In the 'Bilge Roll Damping Details', you can set the bilge radius/depth/offset from the central line, and you can optionally define the bilge keel geometry if necessary.
I hope this helps.