Relative and absolute coordinates in CAD

Absolute coordinates are the origin of the entire boundary of your drawing, which is the default origin coordinate of the CAD system.

The relative coordinates are the coordinates relative to the current point.

Both of these coordinates can be used according to the habits and needs of their own view of which.

First, Absolute coordinates

① Cartesian coordinates (X,Y,Z)

The X -coordinate represents the horizontal direction of the coordinate, and theY -coordinate represents the vertical direction. The coordinates of any point in a two-dimensional graph can be positioned in the form ofX,Y.

② Polar coordinates: distance from angle

You can enter a distance from the origin point and its angle in the XY plane to determine the point. For example, the distance from the origin is ten, and the angle of the X -axis is a certain point of the degree.

second, relative coordinates

① Relative Cartesian coordinates: @dx, dy relative to the previous point of the coordinate increment

② Relative polar coordinates: @ distance from the angle remember that relative coordinates are relative to the user's coordinate system, and that the absolute coordinates are relative to the world coordinate system origin.

The relative coordinates in the ACAD are denoted by the symbol @

For example, the 1th has been determined, the 2nd input @20, the 2nd to the 1th X -axis of the distance is a,Y -axis direction is a. If it is a three-dimensional coordinate, the Z -axis direction distance is also input (such as input ,A.).

The @ can be either a Cartesian input method (above), or a polar coordinate, for example, @27<45 is the distance , the 1th radius distance is, but to X The axis rotates counterclockwise from The starting point to determine the second point.

here to explain:ACAD default to the right hand rule rotation angle is positive.

Triangle Efaro, in addition to draw the 3rd, in a knock on the C key (is the closed command simplified input), long closed and became.

Why don't I enter @ when I use CAD to draw relative coordinates? /For example, I directly input the 1th in the CAD ,and then input, when the time is not input @ and input @ to get the same result, I use the mouse to directly capture a point to try the same.

Note that the input command to the command line and the dynamic input situation, these two situations with bad words prone to error, you follow my writing below carefully try.

1. Cartesian coordinate system

The Cartesian coordinate system, also known as the Cartesian coordinate system, has an origin (0 ,0) and two perpendicular axes of the original point. The horizontal direction is the X axis, the right is the positive direction, the vertical direction is the Y axis, and the upward is the positive direction. Any point on the plane P can be defined by the coordinates of the x and y axes, i.e. a pair of coordinate values (x ,y) are used to define a point. For example , the Cartesian coordinates of a point are (3, 4).

2. Polar coordinate system

Polar coordinates are composed of a pole and a polar axis, and the polar axis is horizontally to the right. Any point on the plane P can have the connection length of the point to the pole L( > 0) and the line to the polar axis of the angle a (polar angle, counterclockwise direction is positive) defined, that is, with apair of coordinate values ( L < a) to define a point where "<" represents an angle. For example , the polar coordinates of a point are (5 <).

3. Presentation method

⑴ Absolute Coordinates: relative to Origin

① Absolute Cartesian coordinates: X value Y value

the X ,Y coordinate of the point

② Absolute Polar coordinates: Distance value < angle value

the point to the coordinate origin distance and the point to the Origin line and the X -axis angle.

⑵ Relative coordinates: coordinates relative to a particular point (shifts the coordinate system to the current point as the origin or pole)

① Relative Cartesian coordinates: @X value, @y value

② Relative polar coordinates: @ Distance value < angle value

Relative and absolute coordinates in CAD