selecting surfaces in mechanism for cam

Some things that come to mind when I hear about surface or surface selection problems (though I don't know the direct answer): a.. Imported models which may contain facet features b.. Discontinuous or broken surfaces c.. Unmerged surfaces with yellow edges d.. Poor tangency of surfaces which ought to be continuous (although seed/boundary works on just about anything ~ how are you creating it? don't think I've done one since WF!) e.. Quality of extruded curve upon which plate cam is based (if you can't chain the curve, you won't be able to chain the surface based on it); never seen a spline curve fail (can you chain the surfaces any other way than seed/boundary, e.g., pick surface, move cursor slightly and pick again to highlight pink, hold shift and select a neighboring, non-adjacent surface (or shift RMB and pick from menu, hopefully you'll get 'Intent" surface) and select. f.. Could it make a difference what type of cam? plate? barrel? seems like the least likely possibility However, in mechanism, when picking surfaces for a cam, I know of no reason you wouldn't get the full selection palette. Have you tried online, like the knowledge base? Maybe start here: