# RFEM – Online Manual

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# 11.3.1 Work Planes

### Work Planes

A spatially defined model can only be displayed in two dimensions on the screen. Defining objects graphically is therefore a problem, because which plane they are created in when clicking into the graphic window must be organized. The work plane determines, which coordinate is always "fixed".

The axes of coordinates of the current work plane are displayed as two green, orthogonal lines. The intersection point of these two lines is called the "origin of the work plane".

Normally, a work plane is parallel to one of the global planes XY, YZ, or XZ that are spanned by two axes of the global coordinate system. It is also possible to specify the work plane directly as a plane with any inclination or to define it by means of line, member, and surface axes.

To open the Work Plane dialog box with the parameters of the work plane, select the menu entry

• Tools → Work Plane, Grid/Snap, Object Snap, Guidelines

or use the toolbar button shown on the left.

The dialog box shown in Figure 11.34 appears.

Parallel to global plane XY / YZ / XZ

The work plane can be aligned to be parallel to one of the following global planes.

Table 11.3 Selection of work plane
Plane Selection in Work Plane dialog box Selection in Toolbar

XY

YZ

XZ

To find more options for defining work planes, use the menu item

• Tools → Select Work Plane

or the corresponding toolbar buttons.

3 Points Plane

In the work window, you can select three points that define a new work plane with the axis system UVW. The points must not be defined on a straight line.

Plane with line in X / Y / Z

The work plane is defined by one of the global axes and a line that you determine graphically in the work window. The zero point of the new work plane is placed into the start node of the line and the axis U is aligned parallel to the selected global axis. With this, you can quickly shift the work plane into a roof area, for example.

Plane with member axis xy / xz

The planes of the member axes xy ("weak" axis) or xz ("strong" axis) are used for defining the work plane (see Chapter 4.17). The relevant member must be defined graphically in the work window. The zero point of the new work plane is placed into the start node of the member.

Plane with surface axis xy

The work plane is defined by the xy-axes of a surface that you determine graphically in the work window (see Chapter 4.4). The axes of the new work plane are called UVW (see Figure 11.30).

Offset of work plane

You can use this function to shift the work plane perpendicular to the current plane. Specify the distance in the Offset Workplane dialog box.

The offset remains active until the function is canceled in the menu.

Origin of the work plane

The Work Plane dialog box (Figure 11.34) manages the zero point (origin) of the work plane. Use to select a node in the work window or to define a new node. It is also possible to enter the coordinates of any point directly.

The zero point of the work plane can also be defined graphically by selecting the menu item

• Tools → Select Work Plane → Define Origin

or using the corresponding toolbar button.