Blending curves on the surface [possible feature request]

Is there any other way to blend curves on the surface without pulling them to the surface?

blendCrv.3dm (82.9 KB)

If there is nothing like that, then I would like to ask about adding it in future to Rhino (feature request).
I’ve read that something like that was a feature request some time ago: WISH: blend adjustable curve on surface but I’m not sure if it`s still valid in v8. If not please add it to the list again.

I think it could be helpful to blend curves/edges already on the surface to split/trim.

Hello- what should happen if the input surfaces are not continuous at the level you ask for on the curve?

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IMO first priority should be: Be on the surface. Rest should maintain continuity in every other places and directions.

Same as you can do a continuity on a flat surface.

Maybe it’s not the best example but we may bend this surface and the red curve should follow surface curvature in the first place

I think I know what are you saying but the G1 curve after rebuilding to G2 will meet only G1 accuracy but with CP count of G2. The same should be here. Maybe in your question case some CP will be unused with changing shape (you can raise CP count without changing the shape).

So in other words even if you ask there for G1 curve on G2 surface it will be G2 which looks like G1 but lays on G2 surface.

Well, I mean what if you ask for a tangent blend where the inputs are less than tangent? or G2 when the inputs are less than G2? What should happen?

I don’t see any way other than pulling - even if we do this automatically - the curve to the surface and hoping for the best.


I can no longer find a video on the net (I think it was by Catia v5) in which you could see the operation of the “blend curves on surface” command. Years ago I posted this also here on discourse … I don’t know how to find it.

once the command has been started and the curves have been chosen, in addition to the blend surface on which the curve should lie, from the drop-down menu it is possible to choose whether to have a continuity in G1 or G2.
No need to project the blend curve …

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