curve:eval-pos
List of: Scheme Extensions
Subjects: Construction Geometry
Contents: Kernel

Action: Evaluates an edge or a curve at the specified parameter.

Filename: kern/kern_scm/crv_scm.cxx

Syntax: (curve:eval-pos edge-or-curve parameter)

Arg Types: edge-or-curve curve | edge

parameter real

Returns: position

Errors: EDGE with no CURVE

Description: The parameterization of all curves is normalized to lie in the interval 0 to 1, therefore, evaluating at parameter=0 indicates the start point of the curve.


edge-or-curve specifies an edge or a curve.


parameter specifies the position on the curve to evaluate. If the specified parameter lies outside the range 0 to 1, this extension returns an extrapolated position. A spline can only reliably be evaluated for parametric values from 0 to 1; if parameter is outside of this range for a spline edge, the returned value is meaningless.

Example: ; curve:eval-pos

; Create a circular edge.

(define edge1


(edge:circular


(position 0 0 0) 38 0 100))

;; edge1

; Evaluate the edge at a specific parameter.

(curve:eval-pos edge1 0.75)

;; #[position 9.83512371389579 36.7051813989846 0]
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