so I'm trying to make a headtube for a bike, and I am using multiple sketches with curves that I then patched to fill them in. 3 faces worked, but this last one doesn't. fusion just does nothing, and gives no error. as far as I'm concerned I did everything identically to that bottom face that worked just fine. does anyone know why this might be?
@wersy wrote:
Forum member "Ernst" changed the rails in order to get it more smooth using SE.
Ernst could do the same in Fusion!
Here is how that works, in SE or SW as well as in Fusion:
All the rails approach the profiles perpendicularly, which makes it easier or even possible for the kernel to compute tangency.
The area I marked with a curve isn't an arc, it is a spline.
What very few people ever figure out is that control point splines with no internal spans in Fusion create better surfaces than fit-point splines.
Fusion may still not quite create the surface quality SE, or SW will, but still much better than in the original model.
As usual, I refer to one of the best software documentations for surfacing the Autodesk Alias Theory Builders.
Surfacing is THE discipline where it matters to understand what is going on under the hood of your application.
That is not a dumb question at all! 3D sketches and a blend curve are certainly one way to accomplish this. A blend curve - as currently implemented - is a fit-point spline, which might be OK for this model.
Surfacing almost always requires a bit of experimentation.
@TrippyLighting schrieb:Surfacing almost always requires a bit of experimentation.
Ernst obviously took this sentence very seriously 🙂
In his new design he only uses 2 areas.
@TrippyLighting schrieb:Very nice!
I wonder how that helps @carterbilawchuk achieve this in Fusion.
I'm afraid it won't help. I've just tried it out.
For example, this edge cannot be connected tangentially in Fusion.
That connection should be G2, not G1.
It can be set to Curvature (G2), but it won't ever really be.
Even the original surface, while slightly better than the one created in Fusion, isn't perfectly tangent or curvature-continuous across the entire circumference.
For reasons I've already explained, that cannot be achieved with a boundary patch. It isn't software-specific. One has to understand what a boundary patch is!
It is still (obviously) a NURBS surface, which, by definition, is a four-sided surface stretched over/through the boundary. That has limitations!
The blue highlighted face is the untrimmed patch. Different geometric modeling kernels do that differently.
Fusion's surfacing abilities still need improvement, but the patch tool has improved in recent years.
With the "right" settings this looks pretty nice in Fuiosn:
I did get it to work very similarly to how you have it. heres how I did it:
I simplified the sketches significantly, only having a side profile and the middle guide
them I revolved half the headtube 180 degrees and extruded the profile to patch to, to be able to make eveyrthing tangent
I then repeated that for the top as well, but also using the bottom patch for tangency.
thanks so much everyone for the help, if you want to see more about this project, you can check out my instagram @eulerbikes
