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Surface join, match surface question


New member
Hello All,
Please excuse me for being all over the place with nomenclature in this post, I am not familiar with Rhino v4 and discribe it as I see it.
I am drawing a bike frame.
On the bike frame are 1" tubes with bend radi at the angle changes. These radi are typically 3" centerline.
I have the tube centerline wireframe created to my liking and I'm trying to "flesh it out" by extruding a circle along the curve, creating a surface that look like a tube.
I would like to join these individual surfaces to create a polysurface and add the fillets or curves to that to create the proper bend radi corners.
I tried using the polyline for the extrude but the plane of the circle doesn't change as it goes around the corner and the tube surface flattens out.
I tried splitting the polyline into individual curves and extruding them one at a time. The tube stays correct because the plane stays the same but now I have a problem trimming or intersecting the 2 surfaces to get a common, correct surface edge. At the minor bends this doesn't seem to be an issue but at the major bends, 60 deg, it gets really confused.
Intersect give me a very weird polyline. I suspect it is trying to join the surface wireframes in the order they were created and they do not match up. I saw no way to pick the points in order to create the proper intersect line.
If I make the surfaces overlap, trim becomes confused and only does a partial trim on the surface.
Match Surface doesn't know what to do with the gap on the outboard side of the bend if I extrude the surface using the proper length centerline curve.
I'm lost, HELP.
Again, please keep in mind, after I trim these 2 surfaces to make a common corner, my intention is to join them into a polysurface and try and put the bend radius back in.
Thank you for your time, Rick.