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Coordinate system

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Revision as of 14:24, 25 February 2012 by Clive (Talk | contribs)

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The Coordinate system

In order to get the best out of LibreCAD it is wise to have a good understanding of the coordinate system and how coordinates work. Everything that you draw in LibreCAD will be exact and precise and will be placed there accurately based on the X,Y coordinate system.

The absolute origin or Zero point in your drawing is where the X and Y axes cross each other (represented by a Red cross),every entity you draw is located in relation to this origin.

In LibreCAD there is also the option to set the Relative Zero Point (small red circle).This Relative zero point can be temporarily set to a new location in a drawing so that all subsequent X and Y coordinates of entities drawn or blocks placed for example will be relative to this newly set Relative Zero Point.

In libreCAD`s 2D coordinate system all X units are measured horizontally and all Y units are measured vertically.Coordinates can also be shown as 'Positive' (+) or 'Negative'(-) values.

Examples of X and Y coordinates
Selection 011.png


Basically there are two types of Coordinates Cartesian and Polar.

The Cartesian coordinate system is generally the standard system used in most CAD programs. A specific point in a drawing is located by exact distances from both the X and Y axes - for example a point in a drawing could be 60,45 (note the comma -, separates the two numbers).See example Image below.


Coordinates 60,45.png



The Polar coordinate system will achieve the same result but uses one distance and one angle to do this - e.g. 60<45. Note that 60 is the unit distance and 45 is the angle! see example image below.


In LibrecAD lines,points, Arcs, Polylines, Circles and many more entities can be drawn and placed in a drawing using either Absolute or Relative coordinate input.

Absolute coordinates (description to follow)

Relative coordinates (description to follow)

Absolute or Relative Polar coordinates (description to follow)