Surface Patch on a Concave Surface?

[Anonymous]

I am trying to create a complex-curved solid from surfaces.  I was able to successfully model 5 out of 6 sides (shown here) using sketches and the top side using the patch tool.

But the final side I need (shown here)

Unlike the convex  top, I was unable to use the patch tool to create the concave bottom. Even the best surface option ended up being all wonky (See following:)

How do I get an even surface?

Thanks much.

[TrippyLighting]

Could you share your design ?

In general you can probably use a loft with two rails. It creates a better surface when compared with the crappy patch tool.

You'll see the difference when stitching. If you turn the tolerance down to say .0001mm, with the loft tool all edges to be stitched will still be green, whereas with a patch you'll have to se the tolerance much higher e.g. .01mm.