Creating symbols

When you create symbols, it is imperative that you understand a few basic questions:

  • What size should the symbol be?

    • Symbols in their actual size – Symbols that depict concrete objects (e.g. window, nut, switchboard) should be drawn in their actual size.

    • Abstract symbols – Abstract symbols that only refer to an object, but do not show the actual physical appearance of the object, such as schematic diagram symbols.

    • If you are using an application program (such as Electrical), you should follow the guidelines set by the application, when creating your own symbols.

  • How to use layers in a symbol?

    • Objects within a symbol can be on different layers. This enables you to separate different parts of a symbol (text objects on their own layer etc.). When you insert a symbol, the objects placed as follows:

    • The symbol itself is registered to the layer it is inserted to.

    • The objects within the symbol register to the layers they were on, when the symbol was created. The only exception is, if the objects within the symbol were on layer 0, when the symbol was created, these objects will be registered to the same layer on which the symbol is inserted to.

    • If separate objects within the symbol are on different layers, turning some layers off may result in a situation, where some parts of the symbol are visible and some parts are not. This may seem confusing at first. It is helpful to remember, however, that an object retains its layer information even if it is part of a symbol.

  • How to use colors in a symbol?

    • When creating symbols you must also decide what color to use on different objects. This is important, since you can not change the color of an object within a symbol.

    • Symbol itself also has color information. This color applies to those objects within the symbol, that were created using the color 0. If you change the color of a symbol, all the objects within the symbol that were created using color 0, will also change their color.

    • We recommend that you use the prevailing standards when selecting a color for an object. If you are using a application program, you must use its color scheme.

  • Use of grip points: Normally you can use the object snap to fix on a symbol insert and its snap points. By embedding point objects to a symbol you can create special grip points that react to node mode object snap. If you don’t want these point objects to be visible, you can turn them "off" by setting the PDMODE system variable to 1.

    When inserting a symbol, pressing Tab will shift the symbol insert point to the next grip point while you are still dragging the symbol.

  • Use of attributes.

  • Principles behind User menus:

    • It is easy to create symbols and place them into your own icon menu by using the Symimenu function.

    • The SYMIMENU command lets you automatically create an icon menu, and places the created symbol in it. The IMCUSTOMIZE command lets you edit any icon menu.

    • The SYMBOL icon menu has icons for five user symbol (USERSYM, USERSYM2...USERSYM5).