Join and join edge problem

I seem to be having difficulties with the join and join edge commands. the issue seems to come from attempting to join multiple edges to a single one(which is not as dissensible as it sounds.) when I attempt to use join on the join command on the secluded object that vaguely looks like I chopped it off a boat (because I did,) the edges between the large flat surface on the side and the three surfaces on the side. if I attempt to use join edge, I end up with a zero-length edge at the intersection of the top two side surfaces and the large green flat one. is there any way of rectifying this without severely distorting the model?
here is the model in question:

Hi Kikkolee- use MatchSrf, for Position only and Refine checked , and ‘Match by closest points’ to match the edges of rh curvey surfaces to the planar one.


that did the trick. thank you! I am still not sure why rhinoceros is so finicky about this. it seems quite strange.

Join does not change geometry like MatchSrf does. Join is just a tolerance test. If the edges are within 2X tolerance, they are tagged as Joined and no additional edges can be Joined. JoinEdge lets you override the tolerance so it is never a good choice in this sort of situation. Fixing the surface edge locations using MatchSrf so they are within tolerance is the correct modeling approach. Then the surfaces will pass the tolerance Joining test and you’ll get a good model.

I know. I found it strange because the edges of both surfaces were created from the same curve, and I looked at information on nurbs that said these should have had edge and tangency continuity.(the curves had coincident edge control points and collinear points that connect to said coincident set.) I did not mention it because my mind suddenly became unable to put this concept into words for about three days.