It takes a while to transition from RISA to SAP2000. The two programs are just organized very differently.
First, can I assume this is about P-Delta behavior or capturing geometric non-linearity? If so, then consider two things:
1) SAP may not need as much meshing of the members because it can capture the P-little delta due to nodal rotation as well (i.e. member curvature).
2) Some meshing of the columns or such could still be required. Go to Assign > Frame > Automatic Frame Mesh to set some setting related to this.
If this is NOT related to geometric non-linearity, then I'll give some alternate suggestions in my next post.