Hi Aneesh,
RMxprt is a template-based electrical machine design tool, therefore the user can only change a few parameters. If you want to design rotor bars not occupying the entire rotor slot area, I recommend using Ansys Maxwell.
From RMxprt, the Maxwell geometry model and setup can be created automatically. Please run the RMxprt model, then go to the top Menu -> RMxprt/ Analysis Setup /Create Maxwell Design.
Thanks.
Ivonne