The “Repair->Adjust” tool group in SpaceClaim has some options to help with this. You can use the “Simplify” tool to automatically try to reduce spline surfaces to simpler, mathematical surfaces. The “Relax” tool can also be used to reduce the number of control points for spline surfaces/NURBs. A more manual approach would be to detach and delete the troublesome surfaces, then recreate them using a patch fill based on tangency from neighboring faces. See this video for a demonstration: http://www.spaceclaim.com/en/Support/Tutorials/Modules/SpaceClaim_Advanced_Repair.aspx?t=143