T-splain extrude - no faces

[mirmetY2P6N]

Hi Guys

I was working on a tutorial but I got stuck. The problem is t-splain extrude. Sometimes works and surface has faces but sumetimes not. Like on screen, curve below. 

I was try couple time with different points quantity but I didnt find solution. Its some kind of bug ?

Best regards

Martin

[jeff_strater]

please share the design.  It is not clear what you think is wrong here.  Do you want more faces along the length of the arc?  If so, you can always use Divide to split the faces after the extrude.

[laughingcreek]

can't tell you WHY.  but I can tell you when it will happen.  and I think it's probably a bug.  if you extrude from a curve drawn while in the form environment, the dialog box will look like the one you pictured.  if you extrude from a curve that was drawn in the modeling environment before entering form mode, you get a few more choices in the dialog-

[adam.helps]

Ah. I don’t think that’s a bug, I think it’s a poorly explained feature.

Curves drawn in the modeling environment default to cubic NURBS. And when you extrude a cubic NURBS into a T-spline surface, the extrusion is exact. There is no need for approximation options when no approximation takes place. Making it exact does require that the T-spline surface be structurally the same as the source spline, though.

Curves drawn elsewhere in Fusion default to quintic (degree five). Since we only have cubic T-splines, we can’t extrude quintic curves exactly (5 > 3). Thus, we ask you what kind of approximation you want, because we aren’t going to be able to make a surface that follows the curve exactly.

Perhaps it could have been handled better/differently, but I think it probably was intentional.