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Why does a split interpolite spline become a control point spline ? (#1926)
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Tim Olson  
#21 Posted : Tuesday, January 20, 2009 8:36:53 AM(UTC)
Tim Olson

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>>Can I be nosy and ask why are you
>>joining these curves together if they already touch?

If you are making a skin or a net surface, each section must be one continuos curve.


>> IMO joining two curves with G0/G1 cont. should not effect the structure or >>density of the curve, it should just modify a few cv's here and there - Tim ?

When we join a curve, the result is G2. The fitting algorithm throws in tons of points to keep the nearby tolerances. Downstream solid modeling operations do not liking working with non continuous curves.

Tim
Tim Olson
IMSI Design/Encore
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jol  
#22 Posted : Tuesday, January 20, 2009 10:10:04 AM(UTC)
jol

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Tim .. can I suggest a short term measure ..

let's throw a dialog up saying that the 2 curves are not curvature-continuous .. and the resulting derivative may be overly complex .. suggest adjusting tangency first

!?
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unique  
#23 Posted : Wednesday, January 21, 2009 2:08:35 PM(UTC)
unique

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Joined: 6/24/2008(UTC)
Posts: 591
Originally Posted by: Tim Olson Go to Quoted Post
>>The isolines resolution option is behaving correct. Curves are calculated at constant u,v locations across the surface. The UV locations are divided up based on the number you are requesting. I use isolines frequently to really see what's going on with the surface, in particular how smooth it is or if there are any degenerative locations in the surface.


Well okay then....but take the VC3 file attached, I would have expected to see the same isocurves in VC when lines are set 1/1 - see image from Rhino this looks consistent with the point structure of the curve whereas VC doesn't somehow ??

Originally Posted by: Tim Olson Go to Quoted Post
I think what you may be asking for is some way to see the actual control vertices as curves which I would find useful as well.


Not sure what you mean here. Maybe I have answered this above.

I look forward to your comments
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unique  
#24 Posted : Wednesday, January 21, 2009 2:45:03 PM(UTC)
unique

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Originally Posted by: Tim Olson Go to Quoted Post
>>Can I be nosy and ask why are you
>>joining these curves together if they already touch?

If you are making a skin or a net surface, each section must be one continuos curve.


I will never like the current "join" it is way too restrictive and I have no control over the result !!. If I want to join 2 or 3 curves which are G1, I expect the curves to remain indentical when joined, so that if I choose to explode them back to their original state they become the same three curves.

Originally Posted by: Tim Olson Go to Quoted Post
>> IMO joining two curves with G0/G1 cont. should not effect the structure or >>density of the curve, it should just modify a few cv's here and there - Tim ?

When we join a curve, the result is G2. The fitting algorithm throws in tons of points to keep the nearby tolerances. Downstream solid modeling operations do not liking working with non continuous curves.

Tim


Thats surely a bad move...tons of points means complex noisy curves, building heavy geometry which will slow things up and when pushed downstream will surely cause even bigger problems....:confused:

Why cant we keep simple clean stuff please?
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