Can a polysurface be converted into a regular surface?

I want to blend these two surfaces and I was thinking I’d get a cleaner transition if I could simplify the upper (vertical) surface (122.3 KB)

Hi James, ‘Explode’ a polysurface to break it down to the individual surfaces.

Use the ‘split’ command using the ‘isocurve’ command line option and ‘toggle’ to required split orientation, then pick the end point of the a curve (for example) to align the split.

and… if you are blending, the result may be nicer if you split away the radiused corners of the bottom surface using some construction curves.

If a pair of surfaces with a common edge are not trimmed then you can use MergeSrf to merge the surfaces. However, if the pair of surfaces do not have appropriate continuity across the shared edge (G2 for surfaces which are degree 3 in the direction parallel to the edge) then, depending on the options used in MergeSrf, “kinks” will be introduced into the new surfaces, and/or the new surface will have a different shape than the original surfaces. Either of these may be undesirable.

I was able to get a full surface for the upper part of this by pulling the lower rail to an extrusion of the upper rail. I made a sweep and then was able to blend the surfaces. Still, the surface seems less than ideal and I was wondering if it’s possible to rebuild the blended surface while forcing it to maintain it’s border edges. What happens normally with a rebuild of this sort of surface is a pulling away from the surface edges that it was derived from. (144.9 KB)

FitSrf can be useful for rebuilding surfaces which have acquired too many control points, while having some control over the shape.