[brlcad-devel] working with ON_BezierCurve

[crdueck <cr...@uw...>]

hello,

i have a few questions regarding working with ON_BezierCurves. I want to 
evaluate the tangents at the start and end points of a bezier curve. the 
function ON_BezierCurve::TangentAt() seems to be what i want, but it 
takes a double as its argument instead of a point. what does the double 
represent? distance from the beginning of the curve? how can i get the 
tangent at the beginning/end points of the curve?

also, is it possible to access specific control points of an 
ON_BezierCurve? I'm mostly concerned with the first and last points of 
the curve. the ON_BezierCurve::PointAt() looks close, but again, it 
takes a double as its argument and i'm not sure what to do with it.

thanks,
chris