Here we'll cover the modify tools, which give us control over simple shapes we have created. As the name suggests - we can modify drawing elements.This is what the modify toolbar looks like (if you don't see it, check the modify box in 'view - toolbars'):
The modify tools (from left to right):
Erase, Copy, Mirror, Offset, Array, Move, Rotate, Scale, Stretch, Lengthen, Trim, Extend, Break at point, Break, Chamfer, Fillet, Explode.
Erase - Select this button then a drawing element to erase it permanently from the drawing.
Copy - The copy command will copy any selected drawing elements and reposition where specified by the user, without affecting the original elements.
1)Select the copy button, then select the object(s) to copy then hit return (or right click)
2) Select the base point where to copy from (For example if copying a circle, it would be sensible for the base point to be the centre of the circle)
3)Enter the second point of displacement - this is where the new base point of the copied objects is to be positioned. Note that the base point is not visible, just a co-ordinate in Autocad's drawing system to enable accurate positioning of objects where required.
When quickly copying an object it is quite acceptable to simply pick a rough point to copy and then position an object without specifying co-ordinates, it can then be accurately positioned in the drawing area using the move command.
Mirror - The mirror command will create a mirror image of any selected drawing elements along any line of symmetry specified by the user.
Mirror Tutor
1) Open the drawing file. It should look like the one shown below:
2) Select the mirror command from the modify toolbar (or choose 'modify - mirror' from the drop down menus)
3) Select the blue object (Looks like half a wine glass?!)
4) We are now prompted to specify the first point of the mirror line, choose the centre of the cross marked 'A'
5) We now need to enter the second point of the mirror line, select the centre of the cross marked 'B'
Handy Tip!: To draw a true vertical or horizontal line, hit F8 or click 'Ortho' at the bottom of the command line to enable Autocad's Ortho function, which limits the available pointer selection points to horizontal or vertical positions relative to the first point selected. Ortho can be used with all commands.
6) Autocad now asks if we want to delete the source object. We need to enter 'Y' for yes or 'N' for no (simply hitting enter would accept the default setting of 'no'). Deleting the source object results in a mirrored copy of the original object, without the original object. In this case we want to keep the original object to complete the drawing. Enter N for no followed by enter.
You should now have a simple drawing of a wine glass as below.
Offset - Offset will make a copy of a line or series of selected lines by a specified distance in the direction specified. The example below shows an original red box (50mm x 50mm) with an offset yellow box 10mm to the outside of the original box.
The offset command simply creates a copy of the selected objects, at the distance specified, to either side of the original object.
1) Create a new drawing and draw a
rectangle from a base point of co-ordinates
10,10 at a size
50,50.
2) Select the
offset command
3) When prompted for an offset distance, enter 10 .
4) When asked to select an object, select the rectangle we drew.
5) Autocad then asks for a side to offset. If we select a point outside of the rectangle then a new rectangle will be created outside of the original at a 10mm offset. Selecting a point within the rectangle would create a rectangle within the existing rectangle at a 10mm offset.
Select a point outside of the rectangle.
You should have an image similar to the one shown above. Offset can be used on any shaped objects, polylines, lines rectangles, circles etc and can be a very useful command. The top arc piece of the wine glass tutorial above was originally drawn using the offset command to give a thickness to the glass.
Array - The array command quickly creates copies of a selected object(s) to a specified spacing. The array command can save lots of drawing time when used correctly. There are two types of array; rectangular and polar. A rectangular array would create copies of an object in rows and columns at specified spacings. A polar array would create copies of an object in a circular pattern based on a specified centre point.Shown below are the two types of array. The red objects are the original objects, and the yellow are the copies created with the array.
Rectangular Array
1) Open the Autocad file, select the array button
2) Select 'rectangular array'
3) For select object, select the chair
4) For the rows and columns, we will select 5 each time. This tells Autocad to repeat the object 5 times horizontally and 5 times vertically.
5) For column offset and row offset enter 1000
6) Autocad 2000,2002 users select the
OK button.
An array will have been created with the rows, columns and spacings specified. Your drawing should be similar to the rectangular array drawing shown above.
5) For number of items, enter 12.
6) For angle to fill, enter 360.
(we have just told Autocad to array 12 items about the centre point for a full 360°)
