Traditionally, designers will create their schematic diagrams by drawing lines or polylines, manually placing them on a layer and then breaking the line
to add symbols. The AutoCAD MEP schematic line behaves similar to a polyline, where a user picks several points in sequence, and the line is drawn
as one object. The biggest difference is in how the schematic line is created. Schematic lines are created one of two ways – orthographically and
isometrically. Once the line is created with one of these methods, it cannot be changed to the other method – it has to be re-created. Schematic lines
have their layer information set by the system definition. The behavior of a line is controlled by the schematic line style. To review a schematic line
style, go to the Manage tab – under Style Manager, select Schematic Line Styles. Select the Standard line style. Select the annotation tab. Schematic
lines differ from polylines in that they control this behavior, such as crossing. Set the default to be a jumped line. This will automatically create an arc
when a schematic line crosses another schematic line. For connections, leave the setting to none. This will make the line attach to other lines and
symbols with no connection mark. For start and end connections, select the dot. This will place a dot at the start and end of a standard line style.
Select the flanged line style, and note the differences for how this style is defined. Select OK to exit the style manager. To create a schematic
line, select the tool from the HOME tab. Immediately check the properties dialog. The first step is to select the line style. Next, select the
system for the line. Pick points to place the line – you need at least two points to define the line. Once the line is created, press enter to complete
the command. After the line is created, you may select the line, and change properties for the line – with the exception of the drawing mode and length.
To continue drawing a line from the end of a segment, pick the line. Select the plus sign grip, and check the properties. The existing settings are
maintained, and you can continue to draw schematic lines. To draw a schematic line from the middle of a segment, you can either start a new
schematic line and use the curve connector snap to start anywhere on the line, or you can select the plus sign grip at the center of the line – this will
create a new line from the midpoint of the segment. To move a line segment, pick the line. Select the box grip at the center of the line segment. Drag the
grip in the direction you want – the nice part about this, is that the symbol that is placed on this line will also move with the line, and connecting segments
will also be adjusted. Schematic lines may also be created from lines, polylines, and arcs. I’ll start by drawing a polyline. On the tool palette, right click on
the schematic line tool. Select apply tool properties to – and then select linework. Note how the line is changed to a schematic line, so you can use this
to convert existing schematic drawings you may want to have as an intelligent schematic line. To create an isometric line, change the orientation to
isometric. You can now also change the Isoplane used to create the line. We’ll start by drawing a few line segments, with left as the isoplane, and then
we’ll switch between right and top. When finished, press enter to complete the command. You can now place symbols along and at the end of your
lines, and create your schematic diagram.