Tips on blending spherical surfaces of different radii

Hello, I’ve been trying to blend as cleanly as I can the following surfaces, but I’m having difficulties. When inspecting the result with the environmental map or zebra, I still see jagged areas. The half spherical dome has a 151.5 mm diameter at the base for 20 mm vertical, then there is a 20 mm blending zone and finally the rest of the dome has a 150 mm diameter.
So far, the smoothest result is with curve networks and faired base curves. I’d love to hear suggestions or references to tutorial to help me smooth out the surfaces. The final product will be polished.

polysrf.3dm (402.3 KB)

Hi Wind- I’d shoot for simpler surfaces - see if the attached does you any good.

polysrf_pg.3dm (235.9 KB)

@wind, I mucked around a little more with even simpler (degree3) surfaces and matching only for tangency- I paid a little more attention to the curvature of the input curves(green) The result from zebra is as good as the previous set, I think.

polysrf_pg1.3dm (142.1 KB)


Thanks for the super quick reply pascal. If I understand correctly, the new surfaces were created with EdgeSrf using higher degree curves? Can the base curves be created with G2 continuity (I can only do G0 or G1). The curvature analysis still looks wonky and I assume there is a way to create a smooth gradient when transitioning from 151.5 mm to 150 mm diameter.

Hi Wind- you can usually make the curvature analysis wonky if you give it a small enough range- in this case you can see it is very small. Zebra & Emap are decent…

  • the edge where I put the red arrow is only G1, so I suggested maintaining that between my two surfaces.
  • yes, I used EdgeSrf with simple curves.
  • I used MatchSrf as indicated after making the initial surfaces.