A Cylindrical System () can be used in 2D and 3D where rotational symmetry about the axis is required. The cylindrical coordinate system is not applicable in geometries with 2D axial symmetry. The local coordinate system is defined by (r, φ, a), where r represents the radial distance from the longitudinal axis, φ is the azimuthal angle (in the interval from −π to π), and a is the distance from the origin along the longitudinal axis. In 2D models, only the origin can be specified, whereas in 3D models, the longitudinal axis direction, a, and the radial base vector, er (φ = 0), can be specified as well. These direction vectors are automatically normalized.

The definitions of the cylindrical coordinates in terms of the global Cartesian coordinates r = r(x, y, z) are

If this coordinate system is added as a subnode to a Combined System node, define where it will be active using a selection in the Geometric Entity Selection section. Also, the Name and Coordinate names fields and the Frame list are not available in this case.

Select with respect to which Frame — Spatial (the default), Mesh, Material, or Geometry — the coordinate system is cylindrical as defined by the above transformations. Note that the actual coordinate names — typically (x, y, z) or (X, Y, Z) in 3D — are displayed for each frame, indicating which frames differ from each other in the current model.

Under Coordinate names, the default coordinate names appear in the First, Second, and Third columns — r, phi, and a. In planar 2D models, r and phi are in-plane polar coordinates, and a is the out-of-plane coordinate. Change this names if desired.

Specify the location of the Origin of the cylindrical coordinate system in the global Cartesian system. The default is an origin coinciding with the one from the global system.

For 3D models, enter the Longitudinal axis direction. The default is the z direction in the global system.

For 3D models, specify the Direction of axis φ=0, where φ is the azimuthal angle. The default direction is the x direction in the global system.

From the Work plane list, select xy-plane (the default, for a standard global Cartesian coordinate system) or select any work plane in the geometry sequence. If you choose a work plane, the work plane’s coordinates xw, yw, and zw are used for the definition of the origin and axis.