a spline? In a more general setting of semi-algebraic sets there is the Tarski-Seidenberg Theorem http://en.wikipedia.org/wiki/Tarski%E2%80%93Seidenberg_theorem that says the projection of a semi-algebraic set is itself a semi-algebraic set. As nurbs surfaces and breps defined by them are semi-algrbaric sets this means that the projection must be reasonably nice. I could not discover whether it is always a spline. There are however reasonably nice ways to get splines from algebraic curves, though we are back to an approximation. It would be nice to have an algorithm that is guaranteed to give the precise splines when they exist (as in the example above) and will otherwise give a good approximation, I was not able to find if one has been written, even in the theoretical literature.…
ide into 80 branches, and 80 outputs of explode and 80 dispatches - its my nightmare. Is there any way to do this with parametric Number of brunches? …
, a1200)}) Is there any way I can make this list into {a1, a2, a3, a4, -a5, -a6, -a7, -a8, a9, a10, a11, a12, -a13, ..... , a1200} ? ( 4 positive signs then 4 negative signs and so on) - alternating every nth in general.
or
2. Is there any way (workaround) to get negative angle value from 2 vectors? I know 'ANGLE (of 2 vectors)' component by itself doesn't work and I know why too. I have feeling that the reflex angle output might be useful but again, matter of list manipulation.
Any help would be greatly appreciated. Thanks in advance.
Hyo
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