Not being a mathematician (I just play one on the internet), I have now found that the 'tangent' value, also termed a Gradient, is just the derivative dy/dx of the curve and is the same as tan(angle).  That helps a bit.  It doesn't give me a magnitude for the tangent vector though, just the angle.

Learning about spline curves is like relearning over again.  Some of these maths haven't been touched upon for some time - lots of dust on the old noggin.  Looks like I'll have to dig into some books to seek this type of information.

Now, if this all can be applied to these so-called Natural Cubic Splines, I might have an exact duplication of Poser animation curves.  Methinks the reason why there are no tangents to fiddle with in Poser is because this type of curve doesn't easily model them - it is a point on the curve generator more than anything.  So, let's see what can be extracted that resembles a tangent.

C makes it easy to shoot yourself in the foot. C++ makes it harder, but when you do, you blow your whole leg off.

 -- Bjarne Stroustrup

Contact Me | Kuroyume's DevelopmentZone