Drawing coordinate system and scale setting method

Details Drawing coordinate system and scale setting method Drawing coordinate system and scale setting method

1990-03-13

1991-12-24

Evans, Arthur G.

Communications: electrical

Land vehicle alarms or indicators

Internal alarm or indicator responsive to a condition of the...

340706, G06K 100

Patent

active

050758730

DESCRIPTION:

BRIEF SUMMARY
DESCRIPTION

1. Technical Field
This invention relates to a method of setting a drawing coordinate system and scale. More particularly, the invention relates to a method of setting the coordinate system and scale of a figure drawn on a drawing set upon a tablet.
2. Background Art
There are cases where a drawing as drawn free hand or the shape of a manufactured article on a drawing which does not include dimensions is defined. In such case, the drawing is placed upon a tablet sensing area of a tablet, the tablet device is made to recognize the scale of the drawing or the drawing coordinate system, (the scale or the drawing coordinate system is set), and then a transformation matrix is obtained for transforming the coordinates of the tablet coordinate system into the coordinates of the drawing coordinate system. Thereafter, the coordinates of points on the drawing are found in the tablet coordinate system, and these coordinates are transformed into those in the drawing coordinate system by the aforementioned transformation matrix. This processing is repeated to define the shape of the manufactured article on the drawing.
The method of setting the scale and the drawing coordinate system will be described with reference to FIG. 6. First, the scale is set by directly entering a drawing scale value "S" from a keyboard. Next, one point P on a drawing DW placed upon a tablet is selected and the coordinates (x.sub.0,y.sub.0) of this point in the drawing coordinate system are entered from the keyboard. After which a point Q on the drawing DW which will render a line segment PQ parallel to or coincident with the X axis of the drawing coordinate system is entered, thereby setting the drawing coordinate system. More specifically, the system uses the initially set scale S to obtain axial distance components S.x.sub.0, S y.sub.0, in the tablet coordinate system X.sub.T.Y.sub.T, from the point P to the origin O of the drawing coordinate system. The system thereafter point at distances of S.x.sub.0, S.y.sub.0 from the point P along the respective axes and, regarding this point as being the origin O of the drawing coordinate system, sets the drawing coordinate system on the tablet surface. If S represents the scale, (x.sub.0 ',y.sub.0 ') the coordinates of the origin O in the tablet coordinate system and .theta. the angle of inclination between the two coordinate systems, then transformation equations for transforming coordinates (x,y) in the tablet coordinate system into coordinates (x',y') in the drawing coordinate system will be as follows: ##EQU1## Q in the tablet coordinate system X.sub.T.Y.sub.T.
However, with the conventional method of setting scale and drawing coordinate system, the setting of scale and the setting of the drawing coordinate system involve two entirely different operations. As a result, the setting procedure is a troublesome one.
In addition, the conventional method cannot be applied unless the X-axis or Y-axis direction on the drawing is already known.


SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to provide a method in which a drawing coordinate system and scale can be set by one and the same operation, and in which the drawing coordinate system and scale can be set without knowing the directions of axes on the drawing.
The present invention provides a method of setting the coordinate system and scale of a figure drawn on a drawing set upon a tablet.
Coordinates (xt.sub.1,yt.sub.1), (xt.sub.2,yt.sub.2) in a tablet coordinate system are obtained by selecting two points P1, P2 on a drawing, the coordinates of which points in the drawing coordinate system are already known, and the distance between these two points in the tablet coordinate system is calculated. The distance between the two points in the drawing coordinate system is calculated using coordinates (xf.sub.1,yf.sub.1), (xf.sub.2,yf.sub.2) in the drawing coordinate system. A scale S of the drawing is obtained based upon a ratio of the distance between the two points in the drawing coordinate system and the d

REFERENCES:
patent: 4577214 (1986-03-01), Klie et al.
English Abs. of Japanese A 62278679, Dec. 3, 87.
English Abs. of Japanese A 61108175, May 27, 86.
English Abs. of Japanese A-63104105, May 8, 88.
English Abs. of Japanese A-60 204006, Oct. 15, 85.
English Abs of Japanese A-59 114609, Jul. 2, 84.

Affiliated with

Also associated with

Rating

Drawing coordinate system and scale setting method does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Drawing coordinate system and scale setting method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Drawing coordinate system and scale setting method will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-49636