VS:RelativeCoords

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Description

Translates a point into a coordinate system defined by 2 other points.

FUNCTION RelativeCoords(
             ptX, ptY, ptZ            :REAL;
             begPtX, begPtY, begPtZ   :REAL;
             endPtX, endPtY, endPtZ   :REAL) X, Y, Z :REAL;

def vs.RelativeCoords(pt, begPt, endPt):
    return VECTOR

Parameters

ptX, ptY, ptZ		REAL
begPtX, begPtY, begPtZ		REAL
endPtX, endPtY, endPtZ		REAL

Remarks

(Orso, 2011 Jan. 21): As shown in the example below, it also accepts three vectors. For the math-ignorant (such as me): you can visually understand the effect of this routine as follows:

draw a line between "begPt-endPt". This line has perhaps an angle.
rotate the line using as fulcrum "begPt" so that it lies horizontally on the x-axes. Now the angle is zero
shift the line on the user origin so that "begPt" lies on it

You can see an image of this representation on the Math page of Vectorlab

Example

PROCEDURE Example;
VAR
   pt, beg_pt, END_pt, v :VECTOR;
BEGIN
   Message('Set begin point...');
   CallTool(-221); { call the "Locus" tool }
   GetLocPt(FSActLayer, beg_pt.x, beg_pt.y); { fetch locus coordinates }
   Message('Set end point...');
   CallTool(-221);
   GetLocPt(FSActLayer, END_pt.x, END_pt.y);
   Message('Set point...');
   CallTool(-221);
   GetLocPt(FSActLayer, pt.x, pt.y);
   v := RelativeCoords(pt, beg_pt, END_pt);
   Message('result vector=', v);
END;
RUN(Example);

Version

Availability: from All Versions

This is drop-in function.