Mesh problem

I have designed a model to 3d print.I designed half of it and intend to mirror it and join the 2 objects. I tried to make a mesh to print and I get the error seen in the picture.The back of the model behind the semi circular piece didnt mesh properly.On the closed solid polysurface there is a smooth edge at the back of the vehicle, but the mesh has an irregular edge and there is a section missing behind the semi circular piece.I cant figure out why this happened and how to fix it.Any ideas?

Hello - hard to say without the model but it looks like MergeAllFaces might simplify the planar faces at the back and maybe mesh better.

Best to post the file.

-Pascal

Here is the filescooterrhino.3dm (5.7 MB)

Hello - try to think of the thing as a closed solid - see the attached file - there are several places, probably more that I have not seen, that are not really compatible with that idea, if I understand what you’re after.
scooterrhino_PG.3dm (3.2 MB)

-Pascal

I`m sorry Pascal I dont understand your answer.Are you saying the model is too complex as it is? I made the object by the usual method of drawing curves and extruding them to get solids and then boolean union the solids to get the complex shape.Here is an ealier version that is much simpler but I still get the corrupted mesh at the rear end and I catn understand why that is.I tried the merge all faces and it said there were no faces to merge.Rhino says I have a closed solid polysurface so it should generate a mesh that matches the model.I dont know what to do to fix this.When I exploded the object and then joined it all I got naked edges which I didnt when I originally joined the objects.Very frustrating. I have spent a ton of time on this model and would hate to have to abandon it and unless I understand what happened I am concerned I will run into the same problem again when I re do the model. Do you have any ideas of a solution without starting over?scooterrhino-2.3dm (964.6 KB)

I fixed it by exploding the polysurface ,splitting the surface that had the curve on the back that was corrupted,deleting the curved edge, using the duplicate edge function to make 4 curves the were the edges of the hole I made and then used curved network to make a new curved section, joined all the polysurfaces back together and got a closed solid polysurface.When I did an export as an .stl the rear curved section now is no longer corrupted and has a smooth curved edge which matches the closed solid polysurface profile.I would still like to know what I did wrong initially. I guess I need to keep checking my models as I proceed to make sure the closed solid polysurface actually creates a mesh which matches the solid.
here is the filescooterrhino-2fixed.3dm (1.0 MB)