Pipe, Duct, Cable tray 

Piping
The Pipe element allows you to draw connection pipes between the MEP objects. Like any software entity, it has a section to define the properties before its insertion.
Property

The basic properties are related to the 2D representation, such as color, line type, line thickness. etc.
Note: The priority can be a field that helps to optimize the representation of the design when several pipes pass one over the other because it allows you to define up to 8 overlapping levels.

Moving on to the geometric parameters, we find the parameters for defining the profile-section, which can be circular or rectangular, the material, and other parameters relating to the information associated with the duct, which are used for calculation purposes.

SETS can be saved or recalled to manage frequently used types.

MEP entities are special entities: the properties defined before insertion are valid if the "free" drawing technique is used, starting from an empty point in the work area. Since these are connection elements between MEP objects, in the most common use of the instrument, many properties will be overwritten and set dynamically in relation to the specific situation. (Eg the section is set on the basis of the connectors of the MEP objects, or the colors can be forced on the basis of the system to which they belong).

Insertion

Creating a pipe in the work area is possible in two ways: with a free pipe starting point, or starting from a socket point.
Drawing a pipe with a free pipe starting point is similar to the 3D extrusion, polyline commands, [...].

The commands in the properties bar inform you about the current inclination, which can be modified with the given values or with the "modify inclination" button on the ribbon.

The "vertical movement" allows you to continue the path by moving in height.
Depending on the current situation, the next pipe may have one or two degrees of freedom. This can be changed by clicking on the blue or green grid icon.
It is possible to enter a height difference, or an exact elevation to which the Pipe must move.

Branches
To add a branch you can insert a fitting on the Pipe.

The Tee fitting is among the quick options, alternatively other fittings are present in the library. It is possible to insert them with the Drag&Drop technique. 

The size of the fitting is assigned based on the Pipe it is inserted into. It is possible to modify them by accessing the properties of the single fitting.

By clicking on the green node, you start drawing a Pipe, whose properties remain unchanged with respect to those previously defined, except for the diameter, which is detected by the starting connector.

Editing
If a Pipe route is selected, regardless of the active View, grips appear. The entire segment is recognized as a single polyline if the pipes are connected to each other. Dimension grips show stroke lengths and stroke lengths, if any.

Nodes are connectors that the software automatically generates at the beginning and end of each tube. Red nodes represent connected connectors, green nodes represent free connectors.
Other Pipes can start (or arrive) from a free connector.

Offset and Add Node
By clicking a Grip-side, you can offset the selected side.
The direction of the offset is taken from the active view.
For example, if we perform the operation on a section view, the software fixes it to the vertical direction, while if from a 2D view, it performs the horizontal shift.

The same concept applies to the "Add Node" command.

The software takes care of connecting the Pipes using the Fitting most suited to the angle, using the object defined in the Fittings properties.

Duct
The Duct entity has a similar behavior to the Pipe. It too can have a circular or rectangular profile. The underlying command is basically the same, with the same modeling options. It differs in the logical organization of project elements, for system properties.

Cable tray 
The Cable tray presents a behavior similar to the Pipe. It differs in having an open profile and a dedicated fitting library.