LinearDimension absolute/relative references

I try to get “Rhino.Geometry.LinearDimension” working.
I’m migrating my python code to Rhino 6.
I know annotations changed a lot but I wonder why the parameters have changed from
(plane, absoluteExt1, absoluteExt2, absoluteLinePt)
(plane, absoluteStartPos, relativeEndPos, relativeLinePos).
In that case shouldn’t be better to use vector for relatives values ?
Practically and conceptually, isn’t it odd to know the length of a measure before the measurement ?
(Even the python example is a bit twisted (an absolute position named “offset” ???)

Can I know goal of that change ?


That’s fixed by in SR4

I made a sample code based on Cormier’s example.
I tried to clarified the mindset to adopt to understand the function based on my perspective which is in absolute coordinates.
Maybe it could help.

import Rhino.Geometry as g
from scriptcontext import doc
import rhinoscriptsyntax as rs
import math

#Closest point in a plane (2d result)
def cp(pl, pt):
	b, u, v = pl.ClosestParameter(pt)
	return g.Point2d(u, v)

#Absolute World Coord points
def addLD(e1, e2, pt, aligned=False):
	if aligned:
		cplane = rs.ViewCPlane() #Stays in same plane
		xDir = g.Vector3d(e2-e1) #Calc x and y vectors of the new aligned plane
		yDir = g.Vector3d(xDir)
		yDir.Rotate(math.pi/2, cplane.Normal)
		ldPlane = g.Plane(e1, xDir, yDir) #1st point = origin
		ldPlane = rs.ViewCPlane()
		ldPlane.Origin = e1 #1st point = origin
	#  cp(ldPlane, e1) == g.Point2d(0,0) == origin
	ld = g.LinearDimension(ldPlane, cp(ldPlane, e1), cp(ldPlane, e2), cp(ldPlane, pt))
	ld.TextHeight = 35;
	ld.ArrowSize = 30;

#Absolute World Coord pick
addLD(rs.GetPoint(), rs.GetPoint(), rs.GetPoint(), aligned = False)