Overview

1. Up until now, all objects have been created:

   1. by picking points on the screen

   2. entering co-ordinate values

   3. referencing existing objects, e.g. midpoint, endpoint, etc.

2. There are other methods which enable objects to be positioned on the screen, these being:

   1. point filters

   2. construction lines

   3. ray lines.

3. Drawings contain information which may be useful to the user, including:

   1. co-ordinate data

   2. distances between points

   3. area of shapes, etc.

In this chapter we will investigate several of the above concepts.

Point filters

1. These allows objects to be positioned by referencing the X and Y co-ordinate values of existing objects.

2. Open the A3PAPER standard sheet and refer to Figure 19.1.

   
   Figure 19.1: Point filters and drawing information exercises.

3. 1. draw a 50-sided square, lower left corner at 20,220

   2. ensure that grips are not active, i.e. off

   3. multiple copy this square to three other positions.

4. A circle of diameter 30 has to be created at the 'centre' of each square and this will be achieved by four different methods:

   1. Co-ordinates
      Activate the circle command with centre: 45,245; radius: 15.

   2. Object snap midpoint

      1. draw in a diagonal of the square

      2. select the CIRCLE icon from the Draw toolbar and:

         1. centre point: Snap to Midpoint of diagonal

         2. radius: enter 15

   3. Object snap from

      1. select the CIRCLE icon from the Draw toolbar and:

      2. centre: pick the Snap from icon

         1. base point: Endpoint icon and pick left end of line AB

         2. offset: enter @25,25

         3. radius: enter 15

   4. Point filters
      Activate the circle command and:

      prompt