Coordinates in AutoCAD
When you start drawing the drawing in AutoCAD, you must start the first build at the point with precisely defined coordinates, and not by clicking the mouse anywhere in the drawing area of the drawing.
Every user of the AutoCAD system should know how to enter (specify) coordinates in the AutoCAD.
Input coordinates in AutoCAD, Cartesian (rectangular) and polar coordinate systems in AutoCAD, relative and absolute coordinates
Self-teacher AutoCAD for "Teapots" will help you to understand all the intricacies of work in the AutoCAD system: to learn something new in AutoCAD or to remember the long-forgotten old.
Cartesian (rectangular) coordinate system in AutoCAD (2D space)
For the first time I got acquainted with the Cartesian coordinate system in school in grade 5. All, probably, remember mutually perpendicular to the X and Y axis, as well as the point in the crosshairs of the axes with the name origin of coordinates. Further in the 10th, 11th grades in drawing lessons I got acquainted with the 3D model of a Cartesian coordinate system and the concept of an octant.
In the lessons of geography, physics, we studied geographic coordinate systems - all previously acquired knowledge will be needed to master the task (input) of coordinates in AutoCAD.
In 3D modeling of AutoCAD, we examined the model of the Cartesian coordinate system, or rather in the article 3D space in the Autocad and tied it to the Autocad system.
In the Autocad 2D system, points are defined in the working plane XY, because The Z axis is not used (the imaginary absence of the Z axis).
The working plane in the AutoCAD is like a piece of paper in a cage, if a grid is included. In the rectangular coordinate system AutoCAD, the point is set by two values of the X and Y coordinates. The intersection of the X, Y axes forms the origin point of the AutoCAD. Coordinates in the AutoCAD are separated by commas. Sample of recording rectangular (Cartesian) coordinates (0.20).
The X coordinate in the AutoCAD determines the distance from the origin of coordinates horizontally, Y - vertically. The distances can be positive or negative, i.e. when entering coordinate values in the Cartesian coordinate system, the distance for the point and its direction (+, -) along the X, Y axes with respect to the initial (initial) point of Autocad (0,0) is indicated.
Polar coordinate system in AutoCAD (2D space)
The polar coordinate system is given by a ray, which is called the zero or polar axis. The point from which this ray comes out is called the origin or pole. Any point on the plane is defined by two polar coordinates: radial and angular. The radial coordinate corresponds to the distance from the point to the origin. The angular coordinate is also called the polar angle or azimuth, equal to the angle to which you want to rotate the polar axis counterclockwise in order to get to this point.
Absolute and relative coordinates in AutoCAD
In a Cartesian and polar coordinate system, you can specify coordinates in AutoCAD either in absolute or in relative form.
User and world coordinate system in AutoCAD
Do not forget that in AutoCAD there can be several user coordinate systems, which you can name and navigate among them.
Coordinates are usually specified in the moving user coordinate system (UCS), and not in the fixed world coordinate system (MSC). By default, the UCS and MSC are the same.
In more detail, we examined the PUK and MSC in the self-study manual for modeling in AutoCAD.
How to enter coordinates in AutoCAD or how to specify coordinates in AutoCAD
Any constructions in AutoCAD are reduced to the constructions in AutoCAD by coordinates. Clicking the mouse in the drawing area of the drawing, using object snapping or object tracking, polar snapping, etc. in AutoCAD we enter the values of the coordinates themselves without suspecting it. All created objects in the AutoCad have characteristic (nodal) points (usually in their place appear handles), which position the object in the space of AutoCAD.
For example, the segment in the AutoCAD is constructed by 2 points (the end points of the segment), respectively, we must specify the coordinates of these two points in the AutoCAD. A rectangle in the AutoCAD can be specified by two diagonal angles (by default), therefore, it is required to draw the coordinates of two points of diagonal angles when drawing it.
That is, the task, coordinates input into the AutoCAD can be performed directly with the mouse, entering coordinate values into the AutoCAD command line and as an alternative to it in the dynamic input fields.
In Autocad there are two coordinate systems: Cartesian and polar. To these coordinate systems the absolute and relative coordinates of Autocadas are applicable. Also coordinates in AutoCAD can be set by mouse, input (setting) the values of coordinates in the command line and enter coordinates using dynamic input. Above listed features (functional) AutoCAD allows you to enter coordinates in AutoCAD in various ways (methods).
Methods for specifying coordinates in AutoCAD (2D space)
- The method of inputting absolute Cartesian coordinates in AutoCAD.
- Method of relative rectangular coordinates in AutoCAD.
- The method of inputting polar coordinates into AutoCAD.
- Method for specifying relative polar coordinates in AutoCAD.
- Enter coordinates in AutoCAD using dynamic input.
- Interactive method for entering coordinates, assigning coordinates to AutoCAD by the method of direction and distance.
Consider the methods for entering coordinates in AutoCAD in more detail.
The method of inputting absolute rectangular coordinates in AutoCAD or how to specify absolute coordinates AutoCAD
The coordinates for the absolute method of entering coordinates in the AutoCAD are calculated from the point of intersection of the X, Y axes (the initial point of coordinates (0.0)).
The points to the left of the initial coordinate in the AutoCad will have negative X coordinates, and the points below are the negative Y coordinates. Recall the 5th class of the COL.
- The X-axis is the abscissa.
- The Y-axis is the ordinate axis.
- The coordinate X is called the abscissa of the point A.
- The coordinate Y is called the ordinate of point A.
A sample of the record A (x, y).
The four angles formed by the coordinate axes X, Y are called coordinate angles, quarters or quadrants.
Signs of the coordinates of the Autocad point in different coordinate angles
- The point of the coordinate angle 1 has "+" abscissa and ordinate.
- The point of the coordinate angle 2 has a "-" abscissa and a "+" ordinate.
- The point of the coordinate angle 3 has "-" abscissas and ordinates.
- The point of the coordinate angle 4 has "+" abscissas and "-" ordinates.
Constructing a segment in absolute rectangular coordinates in AutoCAD using the command line
Call the Line command in AutoCAD. A prompt appears at the command prompt:
In response to an invitation to the command line, we indicate the absolute coordinates of the first point (-50, -30). The AutoCAD will issue the following query:
At the command line, specify the coordinates of the second point 100, 50. Note that a comma is placed between the coordinate values in AutoCAD. To end the Line command, press Enter again.
The cut in AutoCAD by absolute coordinates was built, you can see the result in the picture below. Once again, I recall that the absolute coordinates in the Autocad are counted from the origin.
Method for entering relative Cartesian coordinates in AutoCAD or how to specify relative coordinates AutoCAD using the command line
The method of relative Cartesian coordinates The autocad differs from the method of absolute coordinates in that the coordinates X, Y are given relative to the last specified point, and not relative to the origin.
When you enter relative rectangular coordinates through the command line, use the special symbol @ (dog). This symbol is placed in front of the coordinates.
We construct the segment in AutoCAD by absolute and relative rectangular coordinates.
- Call the Line command. Enter the absolute coordinates of the first point of the segment (20,30) on the command line.
- We enter in the command line the relative rectangular coordinates of the second point of the segment @ (0.60).
- As a result, a vertical section with a length of 60 mm was obtained. We introduced relative coordinates relative to the first point of the segment (relative to the previous point).
Method for entering absolute polar coordinates in the AutoCAD or how to specify absolute polar coordinates AutoCAD using the command line
As we have already discussed, the polar coordinates are given by two parameters:
the distance from the origin to the point is the radial coordinate;
angle between the zero direction of the polar reference system and the vector directed from the origin to the desired point-the polar angle or the azimuth.
The polar angle in the polar reference frame in AutoCAD can be either positive or negative.
By default, the angle reading in the AutoCAD is counterclockwise from the horizontal straight line to the right (X axis, polar axis) - the positive value of the polar angle, and clockwise - the negative value of the polar angle in AutoCAD.
When specifying absolute polar coordinates in AutoCAD, a special symbol "<" is used, for example: 40 <30.
- The number 40 is the radial coordinate, the distance to be set at the specified angle.
- The <means that the next value of 30 is the angle value.
- Angle 30 is the polar angle.
Absolute polar coordinates in AutoCAD are practically not used, because polar coordinates are taken from the origin.
Construction of a segment along absolute Cartesian and polar coordinates in AutoCAD
Call the Line command in AutoCAD. At the request of the command line:
We indicate the absolute rectangular coordinates (0,0), that is, the first point of the segment is located at the origin. On the following query, use the command line:
Specify the absolute polar coordinates 40 <30 by typing a string into the command and press Enter.
A segment along the absolute rectangular and polar coordinates in the AutoCad was built.
Method for entering relative polar coordinates in the AutoCAD or how to set the relative polar coordinates AutoCAD using the command line
Polar coordinates in the AutoCAD can also be set relative to the last set point.
To enter the relative polar coordinates in the AutoCAD, use the @ sign (dog) before entering coordinates. Example: @ 70 <50.
- The symbol @ means that the coordinates are taken relative to the last set point.
- The symbol <means that the next value of 50 is the angle value.
- The number 70 is the distance you want to postpone at the specified angle.
Construct a rectangle in the AutoCAD with the indication of the relative polar coordinates
Call the Rectangle command in AutoCAD. AutoCAD will issue a request:
Click the first point of the rectangle by clicking on the free space in the drawing. The following prompt appears on the command line:
Let's enter the relative polar coordinates of the diagonal corner of the rectangle in the command line @ 100 <45 and press Enter.
A rectangle in AutoCAD using the interactive input of coordinates and relative polar coordinates was constructed (see the figure).
Building on coordinates in AutoCAD, entering coordinates in AutoCAD through dynamic input
All previously discussed ways of constructing the coordinates in AutoCAD were made through the command line. AutoCAD allows you to enter coordinates in the dynamic input fields. Entering coordinates using dynamic input has its own peculiarities, consider them below.
To activate dynamic input in AutoCAD, click on the button in the status bar of "Dynamic Input" or on the F12 key.
For more information about dynamic input and configuration of it in AutoCAD when entering coordinates and commands, as well as displaying the necessary information about the object, see the article "Dynamic input to AutoCAD".
Constructing a segment at an angle to the X axis in the AutoCAD using dynamic coordinate input or how to construct the segment at an angle
We construct the segment at an angle to the X-axis (positive-directed to the X-axis) using the dynamic coordinate input. If you use polar coordinates in AutoCAD and enter them through the command line, the record will be of the next type 70 <30.
Call the Line command in AutoCAD. At the prompt of the command line:
We introduce the absolute coordinate X = 0 in the first dynamic input field. Enter the comma from the keyboard. After entering a comma, AutoCAD automatically throws the absolute coordinate Y to the second field, and the X-field blocks. Enter the coordinate Y = 0 and press Enter. Absolute coordinates of the first point of the segment were given by (0,0); the segment originates at the origin.
The following prompt appears:
- In the dynamic field of the length of the segment, we introduce the radial coordinate (distance) 70.
- Press tab key Tab.
- AutoCAD will move us to the second dynamic input field to enter the polar angle. Enter the value of the polar angle 30 in the field and press Enter.
A positive polar angle in AutoCAD produces a counterclockwise rotation, and a negative angle clockwise.
A length of 70 at an angle of 30 in the AutoCad was built.
By default in the dynamic input settings it is established that the first coordinate is entered absolute, and the subsequent ones are relative, so for the following coordinates it is not necessary to enter the @ (dog) sign. This setting is effective for both polar and rectangular coordinates in AutoCAD. If you want to enter directly the absolute coordinates of AutoCAD through dynamic input, you should specify the prefix # (grid).
Construction of segments using polar and Cartesian coordinates in AutoCAD (relative and absolute) via dynamic coordinate input
Interactive method for entering coordinates in the AutoCAD, assigning coordinates to the Autocad by the method of direction and distance
Indexing coordinates in AutoCAD
See in the video tutorial.
Video "Coordinates in AutoCAD"
In this video lesson, AutoCAD will detail each method of specifying coordinates in AutoCAD.
Of course, we can not ignore the dynamic input mapping and the use of the grid. Also we will look at the AutoCAD coordinates display.
This video tutorial Autocad and the article are included in the professional free self-tutorial AutoCAD, which is suitable for both novice users and those already working in this program for a long time.