what is coordinate?can you explain it briefly

[afrazawan]

what is Coordinate?what is mean it please help me with some examples thanks

[Dadgad]

A plane is defined by the intersection of two axii (the X axis and the Y axis, for example).

The coordinate system defines the location of any given point by referencing its location with regards to those two axii (think lines).

Where the two axii (lines) intersect is called the origin, and is described by its location on each of the axii, like this (0,0).

The first number always indicates the location (distance from the Y axis really, measured parallel to the X axis) along the X (horizontal) axis,

and the second number indicates the location (distance from the X axis measured parallel to the Y axis) of the Y value.

Zero is at the origin, when observed in TOP view, a negative X value would be to the left of the origin, a positive value to the right of the origin.

A positive Y value will be above the X axis (viewed in TOP view), a negative Y value indicates it will be below the X axis (in TOP view).

 

http://www.cadtutor.net/tutorials/autocad/using-coordinates.php

 

When working in 3D, a new axis must be added to indicate location ABOVE or BELOW the plane described by the XY plane.

A 3D coordinate then needs another number added to describe the Z value, and will look like this (X,Y,Z).

The Z value will often be described as the ELEVATION, within a 3D environment.

Think of it as the height, either above (+) or below (-) the ground (X-Y plane).

When in TOP view, the Z axis extends up perpendicularly from your screen, and also intersects the origin (the intersection of the X and Y axii).

A positive Z value will be above the XY plane when in TOP view, and a negative Z value below.

In the attached image, which is displayed in an ISOMETRIC perspective you can see the UCS icon indicating the relative directions of the different axii.

The intersection point indicates the origin's orientation relative to the UCS, and the letter describing the axis is placed in the POSITIVE direction from the origin.

 

 

I don't understand why in INVENTOR, the default orientation is different, but everything said previously applies to default Autocad settings.

Edited August 26, 2012 by Dadgad