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reparameterizing part of a curve?
Friday, 30 August 2002 Fri, 30 Aug '02
Darran Edmundson wrote:
Can anyone explain how to reparameterize a portion of a curve? Consider a situation where one is happy with the region u=0.0-0.5 and u=0.75-1.0 but wants to tweak the intervening section without affecting (in the 'u' sense) the outer bits. In my specific case, the curve is polygonal where u is distributed equally over the number of vertices. I would like to choose a number of consecutive vertices along a section of the curve, tweak their positions, resample this section even, all without affecting the u of nonselected vertices. I'll spare you my failed attempts at realizing the above. The more I think about it, the less I'm sure that it's even conceptually possible.I'd start with making a point group that contains just the ones you want to modify (use the expression portion of the group SOP, ($MAPU>.5)&&($MAPU<.75) Now add a spare channel somewhere, make it 100 frames long. Now add a point SOP (don't forget to restrict it to just your group's worth of points), and try something like: $MAPU+chf("sparechannel", fit($MAPU, .5, .75, 0, 100)) By keeping the endpoints at zero, whatever's in between will end up being added to (or subtracted from) the existing $MAPU, just in the restricted u region. It will, however, not prevent the u's from doubling back on themselves. -- Antoine
Cheers, Darran. P.S. Can you cc this to me directly as I'm on the digest version of the list and won't see any responses until midnight, my time._______________________________________________________________________ Antoine Durr Rhythm & Hues Visual Effects 5404 Jandy Pl. antoine(a)rhythm.com Los Angeles, CA 90066 voice: 310/448-7669 pager: 310/232-2961 fax: 310/448-7600 _______________________________________________________________________