iPOGO V5 Users Group - Help Manual

*Methodology Number 1 of 2*
Command:	-5
Alpha Alias:	-Arc Arc
Description:	Computes points on common tangent to two curves
Data Format:	-5 Set RadiusPt1 RadiusPt2 Radius1 Radius2 {[Offset] ... } ;
Problem:	Given point number 20 as the radius point of a curve with a radius length of 250 feet, and given point number 30 as the radius point of a curve with a radius length of 600 feet. Compute the common tangent 41-42 and the tangents 43-44 and 45-46 at offsets of 30 feet from the common tangent.
Solution:	-5 41 20 30 -250 600 -30 60 ;

Data Description

Command	-5	Computes common tangents, sometimes referred to as cross tangents or external tangents, of two curves.
Set	41	Point number of the Point of Tangency (PT) of the first curve. The point number to be assigned to the PT of the second curve is automatically assigned from the Set point number.
RadiusPt1	20	Point number of the previously computed first radius point.
RadiusPt2	30	Point number of the previously computed second radius point.
Radius1	-250	Radius length of the first curve or arc.
Radius2	600	Radius length of the second curve or arc. Enter a positive radius for a curve if the PT for that curve lies to the right of a line directed from the first radius point towards the second radius point. Enter the radius length value for a curve with a minus sign if the PT for that curve lies to the left of the directed line.
{[Offset] ... }	-30 60	Repeating feature of this command. Allows you to define one or more lines parallel to the first common tangent. Enter one or more offset distances to define the additional lines. The second offset will be measured from the first offset, not the initially computed common tangent. The additional points that are computed will be numbered automatically in ascending pairs. If the offset line is to be computed to the right of the preceding tangent or line as directed from the first PT towards the second PT enter the offset distance as a positive value. If the offset is to the left of the preceding line, enter the offset with a minus sign.
End Command	;	All commands end with a semi-colon.

Example Command File

$ Example data set for the -5 (-ARC ARC) command, 
$  Methodology 1

$ Set initial points.
  0 20 1000 1000 ;
  1 30 20 
          -1 60 0 0 900 ;

$ Set points using the -5 command.
  -5 41 20 30 -250 600 
               -30  60 ;

$ Set additional points for drawing lines.
  2 1000 20 20 41 -45 0 0 250 ;
  2 1001 30 30 42 -30 0 0 600 ;

$ Setup feature codes with 
$  cmd  feature, layer, color, style, thickness
  15.1    L1     LINES1   1      1       1 ;
  15.1    L3     LINES3   3      1       1 ;

$ Turn plot on
  91 ;

$ Activate the L1 feature
  15 L1 ;
          $ Draw the lines.
            7 1 1000 20.1 41 42 30.1 1001 ;
            7 1 43 44 ;
            7 1 45 46 ;
            7 1 20 30 ;

$ Activate the L3 feature
  15 L3 ;
          $ Draw additional lines.
            7 1 1000 20 43 ;
            7 1 46 30 1001 ;

Methodology Number 2 of 2

Command: -5

Alpha Alias: -Arc Arc

Description: Computes points on common tangent to two curves

Data Format: -5 Set RadiusPt1 RadiusPt2 Radius1 Radius2 {[Offset] ... } ;

Problem: Given point number 20 and point number 30 as the radius point of a curve with a radius length of 25 feet. Compute the point of curvature on the tangent from point 20 and located 25 feet perpendicular to point 30.

Solution:
-5 41 20 30 0 25 ;

Data Description

Command	-5	Computes common tangents, sometimes referred to as cross tangents or external tangents, of two curves.
Set	41	Point number of the Point of Tangency (PT) of the curve.
RadiusPt1	20	Point number of the previously computed first radius point.
RadiusPt2	30	Point number of the previously computed second radius point.
Radius1	0	Radius length of the first curve or arc.
Radius2	25	Radius length of the second curve or arc. Enter a positive radius for a curve if the PT for that curve lies to the right of a line directed from the first radius point towards the second radius point. Enter the radius length value for a curve with a minus sign if the PT for that curve lies to the left of the directed line.
{[Offset] ... }		Repeating feature of this command. See Methodology 1 for more information.
End Command	;	All commands end with a semi-colon.

Example Command File

$ Example data set for the -5 (-ARC ARC) command, 
$   Methodology 2.

$ Set initial points.
  0 20 1000 1000 ;
  1 30 20 
          -2 80 0 0 300 ;

$ Set points using the -5 command.
  -5 41 20 30 
         0 25 ;

$ Set additional points for drawing lines.
  0 
    1000 979.4 940.2 ;

  1 1001 30 
            -1 0 0 0 25 ;

$ Setup feature codes with 
$  cmd  feature, layer, color, style, thickness
  15.1    L1     LINES1   1      1       1 ;
  15.1    L3     LINES3   3      1       1 ;

$ Turn plot on
  91 ;

$ Activate the L1 feature
  15 L1 ;
          $ Draw the lines.
            7 1 1000 20 41 ;
            7 1 20 30 ;
            7 1 41 30.1 1001 -30.1 41 ;

$ Activate the L3 feature
  15 L3 ;
          $ Draw the last line.
            7 1 30 41 ;

Help for this command was last updated: 06/28/2000 12:09:19 AM

iPOGO V5 Help Manual On-Line

Group:Command:

5) Dist-Dist Intx-5 or -Arc Arc

Group:
Command:

5) Dist-Dist Intx
-5 or -Arc Arc