Extend curve smooth broken

Extend curve with the Smooth option does not work in Rhino 6 - it only extends by arc when this option is selected.

HI John - I do not see this here in the latest, so it may be fixed. Can you post an example?



Hi Pascal - it happens every time here, on different computers, Version 6
(6.3.18090.471, 3/31/2018), with any freeform curve. Instead of smooth extension it extends by arc, keep radius. If you do not see it, it may be fixed indeed on your side only.

The Extend command with the Smooth and Natural options changed from V5 to V6 and it confused me initially. Extend with Smooth or Natural in V5 had the user select where the extended curve ended by moving the cursor. Extend with Smooth or Natural in V6 changed that behavior with the addition of the ToPoint option which is available after the curve to be extended is selected.

Extend > Smooth or Natural > ToPoint in V6 behaves the same as Extend > Smooth or Natural in V5 with the user selecting where the extended curve ends with the cursor.

Extend > Smooth or Natural without ToPoint in V6 only allows the user to select the length of the extension, not where it ends.

John, are you using the ToPoint option? Are you extending an arc with constant radius or a curve with varying radius?

Yes, it allow for smooth extension with the ToPoint option. But when I click the Extend Smooth button, I see the Type=Smooth active so it is logical to expect that it will be a smooth extension, not the Arc-Keep Radius one. Why do we have to select additional option get the command perform its default function?

Can you post a .3dm file with an example of the input curve which causes the problem?

When I use Extend with Smooth but without selected ToPoint the extension only has constant radius if the starting curve has the same constant radius.

Extend with Smooth without ToPoint appears to be the same as Extend with Natural without ToPoint. Both extend the end span of the input curve.

At the closer look the smooth extension of a quite smooth control point curve looks like a fixed-radius one, but in fact it is a curvature-continuous smooth freeform extension, better than in Rhino 5. Therefore I rest my case and thank you guys for looking into it.