Cells

A CELL is a group of elements that are tied together by a cell header. Cells are stored in Cell Libraries, where they can be recalled for use at any time.  Cells are generally used for standard symbols, drawing borders, and commonly used drawing components.

Cells either depict graphical symbols such as a north arrow, section cut mark, or electrical schematic symbol, or they depict physical items such as trees, doors, and structural steel members. Cells that depict graphical symbols are referred to in this manual as "symbolic" cells. These cells are always placed at a scale factor relative to the drawing scale. See the section on Drawing Scales for information on setting the scale factor for symbolic cells. Cells that depict physical items are referred to in this manual as "physical" cells. These cells are usually placed at a scale factor of one, because the size of the cell is the actual size of the physical object. In some cases, such as with the tree cells, the scale factor is a multiple of the actual size of the object. See the cell library documentation for each physical cell for information on setting scale factors.

Several general guidelines should be followed when using cells. These guidelines help to ensure that the finished drawings will have a consistent appearance, and will be easily modified by all CAD Drafters.

• Do not DROP the status of a cell.

• Place a cell at the proper plot scale only, do not use other scales for placing cells

• Line terminators (arrow heads) and item callouts should be placed on the correct levels, according to the level application list.

• Schematic symbols (electrical and P&ID) should always be placed on the 1/16" unit or grid points. The Unit Lock should be ON at all times, when placing cells in schematic drawings. For more information, see the section on Grid and Unit Lock.

Matrix Menus

Each cell library has a matrix menu that can be used to access the cells. Matrix menus are used with a digitizer tablet.  If a digitizer tablet is not available the cells may also be accessed by searching through the cell library. All matrix menus are located in the cell library STMENUS.CEL

Cell Libraries

The following Cell Libraries are available for use. A Cell Library has been created for each type of drawing discipline. These include:

Cell Levels

Most cells are designed to fall automatically on the correct level. Exceptions to this include cells that may be used for more than one purpose. For example, the cell that depicts a pipe end-section may be used for many types of pipes and round structures. Therefore, that cell must be placed "Relative" with the active level set to the correct level. The level symbology display helps to detect cells that are not on the correct level, because they are displayed with a different color.

Cells in all cell libraries have been developed to conform to the Standard Level Applications list. When a different level list is used, the cells may not fall on the correct level. The consultant shall verify that all cells used are placed on the correct level for the project.

Point Cells

Point cells can be identified in the cell libraries by their cell name. In the Facility Drafting cell libraries, all point cell names use a period character "." as the last character of the cell name.

Point cells take on the active level, weight, color, and line style, that is set in the design file. In order to use point cells correctly, the user must set the level, weight, color, and line style to the desired settings before placing the point cell.

Line Terminators

The most common line terminator is an arrow head. District line terminators can either be a font character (as with automatic dimensioning) or a point cell. When the point cell terminator is used, it must be placed with the correct active level and weight setting. Line terminators are placed using an active terminator scale (TS=  ). The terminator scale is always the same as the active scale factor (AS=  ), as defined in the section on drawing scales.

Dropping Cells

The term "dropping cells" means converting the symbol to it's simple elements or components. A dropped cell can not be converted back into a cell.

Cells should never be dropped. There are a few exceptions to this rule. Some cells, such as the Drawing Border, are used as a starting point for creation of the final border. Drawing Border cells may be dropped in order to make project specific changes. Similarly, some electrical schematics cells, primarily the ladder diagram cells and some of the miscellaneous devices cells as found on the matrix menu, are intended to be used as a starting point. These cells may be dropped so that they can be modified for the specific drawing. The size and spacing of the elements within these cells should not be modified.

Creating New Cells

The consultant shall use cells from the District's cell libraries for all drawings. On occasion it may be necessary to create new cells for items that are not included in the District's cell libraries. The consultant may create new cells as required, and shall create these cells on the correct levels to conform to District CAD Standards. The consultant shall provide a cell library and documentation for each cell that was created. The new cells shall not be added to an existing District cell library. Instead, they should be in a separate library that only contains the new cells that were created for the project.