scale bezier spline in context

On 16/07/2013 at 04:20, xxxxxxxx wrote:

User Information:
Cinema 4D Version:   14 
Platform:   Windows  ;   
Language(s) :     C++  ;   PYTHON  ;


are there somewhere some examples on how to properly recalculate bezier spline tangents if you 
have to scale the tangents in context of the spline. the spline offset tool does that, it does respect 
properly concavity and convexity of the spline (so that a tangent sitting in a 'dent' is scaled down 
although it has been moved away from the spline objects pivot). i guess i have to calculate the 
scaling factor with the difference of left and right control point tangent from its previous stage to its 
current stage, but i have no clue how to begin. i have already constructed a list matrices for my spline 
providing smoothed banking spline normals with parallel transport frames.  i am trying to rebuild the 
spline offset tool in some aspects.

thanks for reading and happy rendering,

On 17/07/2013 at 11:35, xxxxxxxx wrote:

Hy there,

I do not yet understand, how you would like to scale that bezier spline. Which one is the "spline offset tool"?


On 17/07/2013 at 12:54, xxxxxxxx wrote:


sorry the topic wasn't chosen very well, i meant scaling the bezier spline tangents for a control point that has been moved. with offset tool i meant the 'create outline' tool, sorry for that too. however i have figured it out, you have just to scale the tangents with the the scaling  factor the control point to control point tangents has been scaled. its actually quite obvious, i got somehow confused i guess.

happy rendering,