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Use style spline to create surface loft of equal degree

Question asked by Adam O'Hern on Jun 8, 2016

I'm thrilled that in 2016 we can define degree 3, 5, and 7 style splines explicitly. I've wanted this for years!


If I create two degree 5 style splines with an equal number of CVs, then loft between them, the resulting surface is, as expected, degree 5 in the direction of the curves, and degree 1 in the other direction (linear). I was delighted to see this, because it means that I can create NURBS surfaces with very explicit math for technical surfacing applications.


This breaks down, however, when I try to add a guide curve going the other direction, even if that curve meets up at the ends of the other two curves. If a guide curve is added, suddenly the whole surface is reparameterized, and the resultant surface is a degree-3 approximation of the degree-5 input splines. I've tried this with sweep, loft, and boundary, and it is true in all cases.


The only exception is to use the "centerline" parameter in the Loft command. This (thankfully) retains the degree of the two end curves, but it still doggedly insists on reparameterizing the guide curve.


Is there any way of creating a style-spline based surface with style splines defining both the U and V parameters of the final surface in SolidWorks? This would go a long way toward using SolidWorks for technical surfacing traditionally only available in higher end surfacing tools.




I've since tried the Freeform tool and even lofting between parallel sections comprised entirely of equal-degree equal-CV profiles, and both re-parameterize the input curves as degree-3 approximations, adding tons of unnecessary complexity to the resulting surface.


It seems very unlikely that there's a way to control the complexity of surfaces, based on my experimentation. This is a shame given that we have this lovely new Style Spline, tantalizing us with its beautiful control! I hope SW adds better support for Style Splines in its surfacing tools over time.