> [...] and since writing
 > spline-based lathe/prism-like meshes is pretty simple, I do not think
 > there is any very serious need for it. But it would be interesting to
 > have macro or patch to perform conversion from old lathe/prism data to
 > most accurate spline.

Hm. Seems that I'll have to implement editing modes for all those 
different "equal" splines :/

Are the different approaches of the two spline systems (finding 
intersections vs. finding vectors) really that much different that it is 
not possible (or not desirable) to create a global spline system which 
does both jobs?

 > I have in my TODO list to add as many spline types as possible in form
 > of patch to source code. It is very simple (from programmer point of
 > view of course :-) )
Good news :)

 >> How are the clock values for the splines of lathe/prism computed?
 > See source of lathe/prism.cpp for details.
Just took a quick look on the source. Right on top I find:

* Linear interpolation is used by default. In this case all n Points
* are used. In the quadratic case the first point is used to determine
* the derivates at the starting point P[1]. In the cubic case
* the first and last points are used to determine the derivatives at
* the starting point P[1] and ending point P[n-2].

This seems to differ again from the way the "other spline system" works 
(where the first point in a quadratic spline is not used for the 
derivate, but as another point on the curve). Didn't have to time go 
into that much further, though.
I also couldn't find the clock computations I was searching, but I'll 
dig into it later.

I *did* find something - Catmull-Rom-Splines. There is an interpolation 
function for them in splines.cpp. Are they broken or did someone forget 
to mention that they are available? ;)

Florian

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