Places a volume based on a cross section you specify. You then create a 3D path to extrude the shape along the path.
This command is especially useful for creating volumes that need to have an unusual,
custom shape or that must negotiate around specific objects in the model. For example,
if you need to leave adequate space for a crane, stretcher, or other equipment to
reach a particular location, the Path 
command enables you to specify the path where the equipment needs to travel, as well
as the appropriate amount of clearance that must be left on all sides.
When you place a volume along a path, the software projects a two-dimensional cross-section along the path that you specify in the model to create the volume. The path determines the location of the volume in the model. The cross-section defines the shape and dimensions of the volume.
Defining cross-sections
When you define the cross-section for the volume, you can select from a standard set
of cross-sections, defined in the reference data, or you can sketch your own two-dimensional
cross-section using the Custom cross-section and the Sketching Controls 
.
When you use a standard cross-sectional type, you can change the dimensions and the cardinal point of the cross-section. The cardinal point of the cross-section is important in determining the shape and location of the resulting volume. The cardinal point is the point at which you want the software to attach the cross-section to the path. All standard cross-section types have cardinal points you can specify in the Place Volume by Path Controls.
For example, in the graphic below, you can see that the cardinal point is located in the center (B) of the cross-section (this is the default cardinal point, 1). If you select a different cardinal point, the actual path would be different.
What do you want to do?