OPEN

Purpose:

To enable a user to update an individual symbol.

Instructions:

1. The user is presented with a simple dialog box containing the various symbols and font sets that are currently available. With the screen cursor, followed by clicking the left-hand button, the user can select the symbol that is to be updated. The system responds by drawing a simple rectangular box round the selected symbol.

2. If the user then clicks OK, the dialog box is then replaced on the screen by an enlarged copy of the selected symbol, created in a drawing form of size 511*511. This representation of the symbol is held in a drawing named FONT<font number>SYMB<symbol number>. It is to be noted that the original font and symbol number will be save by the system, along with the drawing to be used, when recreating the symbol.

3. The user can then modify this symbol using the basic Drafting facilities of the system. In order to assist him the symbol is automatically exploded, that is degenerated into its original geometric elements, for example, contours and chains. Furthermore, the connections and text positions, if any and that would have been established when the symbol was first created and entered into the symbol file, will be shown as internal symbols, showing the point and vector of each connection and text position. The connections will be shown in white and the text positions in red.

Options:

The user can update and/or delete old connections and he can add new connections. The system keeps track of the next free connection number and allows the user to supply all necessary information, namely:

• the connection point

• the connection vector

• the connection code

The adding of new connections is terminated by inputting the command Operation Complete.

The user can update and/or delete text positions and he can add new text positions, in a similar manner as for the creation of a new connection, except where supplying the relevant information, namely:

• the text position

• the text vector

• the text position code

• the minimum height and width

The updating of text positions is terminated by inputting the command Operation Complete.

Result:

When the redefinition of the symbol has been completed, the system will store the symbol in the 'symbol font' file and from which it can be subsequently accessed for copying into a drawing. The modified symbol will then be used in any drawing that contains this symbol, including drawings that may have been created before the modification was made.