geometric calculator

8/13/2019 Geometric Calculator

1/3

Geometric Calculator

Comments by: Odin Cary

This is one of the most overlooked commands in AutoCAD and unfortunately one of the most valuable tools.

Embedded within AutoCAD lies a calculator that cannot only be used for basic arithmetic functions, but also trigonometric

functions, unit conversions and advanced geometric functions.

One function alone has made this tool invaluable to me and I will start with that simple routine.

Example

Draw a square or rectangle.

Now put a circle in the exact center of that polygon.

Here's how you can do it with the Geometric Calculator:

Command:circle

CIRCLE 3P/2P/TTR/: 'cal

Initializing...>> Expression: mee

>> Select one endpoint for MEE:(pick one corner)

>> Select another endpoint for MEE:(pick another corner

diagonally opposite from the f irst)

Diameter/:

What you have just done:

The Geometric Calculator was invoked transparently after the circle command ( 'cal ) and then utilized to perform a point

calculation: the midpoint between two endpoints (hence the expression mee). You were queried for two points in exactly

the same fashion you are queried for two object snap points. Notice that the Geometric Calculator quires for points witha pick box slightly larger than normal.

You can use this technique to find the midpoint between any two points anywhere in an AutoCAD drawing. It is fantastic

when mirroring objects.

Example

Have I gotten your attention yet?

Well, here's another great time saver.

Draw a horizontal line.

Draw another vertical line off of one of the endpoints of the previous horizontal line.

Now offset the last line 1/3 of the way down the horizontal line.

Here's how you can do it with the Geometric Calculator:

Command:OFFSET

Offset distance or Through :'cal

metric Calculator http://www.archidigm.com/lounge/autocad%20tips/geometric%20

3 11/27/2009 1


2/3

>> Expression:dist(end,end)/3

>> Select entity for END snap:( pick one endpoint [1])

>> Select entity for END snap:( pick the other endpoint [2])

Select object to offset:( pick the vertical line [3] )

Side to offset?( pick in the direction of off set [4] )

Select object to offset:

What you have just done:

The Geometric Calculator was invoked transparently after the Offset command and utilized to calculate the distance of

the horizontal line, based upon its endpoints, and divided that distance by 3. The Offset command then received the

calculated distance and allowed you to offset an object by that amount.

You can divide the distance by any number you want and you can also specify a distance by any object snap; e.g.,

dist(mid,quad)/10.

General summary of the Geometric Calculator excerpted from class notes.

The Geometric Calculator :

A basic calculator and unit converter

Command: cal>> Expressi on: cos( 45)0. 707107

+, - , * , / , , ( ) , pi

CVUNIT(value, unit_type, to what unit_type)

Command: cal

>> Expr essi on: cvuni t ( 2, m, f t )6. 56168

Acquiring the Midpoint of any two points in space.

Command: lLI NE Fr om poi nt : 'cal>> Expressi on: (end+end)/2>> Sel ect ent i t y f or END snap:>> Sel ect ent i t y f or END snap:

To poi nt :

Acquiring the Centroid of any REGULARPolygon

Command:MOVESel ect obj ect s: 1 f oundSel ect obj ect s:Base poi nt or di spl acement : 'cal>> Expressi on: (end+end+end)/3>> Sel ect ent i t y f or END snap:>> Sel ect ent i t y f or END snap:>> Sel ect ent i t y f or END snap:Second poi nt of di spl acement :

Pre-designed Functions for the Geometric Calculator:


3 11/27/2009 1


3/3

MEE => Midpoint of two Endpoints => (end+end)/2

ILLE => Intersection of two lines based upon selected endpoints

ILL => same as ILLE but requires point specifications; e.g. ILL(int,end,mid,qua)

DEE => Distance between two Endpoints => Dist(end,end)

NEE => Normal vector off of two Endpoints => Nor(end,end)

VEE => Vector off of two Endpoints => Vec(end,end)

VEE1 => Unit Vector off of two Endpoints => Vec1(end,end)

These Functions can be used as per the following example:

Command: cCI RCLE 3P/ 2P/ TTR/ : 'cal>> Expressi on: mee>> Sel ect one endpoi nt f or MEE:>> Sel ect anot her endpoi nt f or MEE:Di amet er / :

Other Useful Functions for the Geometric Calculator

ANG(ApexPt1, Pt2, Pt3) => Returns the Angle derived by 3 points in space; e.g., ANG(int, end, end). Pt 2 to

Pt3 direction will determine value of angle relative to AutoCADs counter clockwise "Angle Direction" Default

Setting.

PLD(Pt1, Pt2, Distance_Value) => Returns a point along a line based upon the Distance_Value relative to

the First Point (Pt1) and the angle determined by the Second Point (Pt2 ); e.g., PLD(end,end,3) will return a

point on a line 3 units from the First Point selected.


3 11/27/2009 1

geometric calculator

Documents