This option defines a variable load defined at 3 points acting on an area defined by a user. Open this dialog by clicking 
on the Surface tab of the Load Definition dialog.
This type of load acts on planar elements. It can also be distributed on bars, if it is applied to a cladding. If so, the load is distributed according to the trapezoidal and triangular method only.
The dialog has the following 3 parts:
- Load Parameters
- Direction of contour projection
- Contour definition
The dialog has options that lets you define variable loads p, applied to a user-defined contour.
To define this type of load, specify the following:
- The load component values acting along the axes X, Y, or Z of the coordinate system. A load can be defined in the global coordinate or local coordinate system of an object.
A variable load can be defined by assigning load values in 2 or 3 points. These can be nodes of a defined planar FE or any points of defined coordinates.
The load distributed over the element surface can be applied to plate or shell structures. The load direction is defined with respect to the global coordinate axes. The load value at any point is then linearly interpolated or extrapolated on the basis of the load values assigned in selected points.
- The direction of the contour projection. This is the direction along which the defined contour (to which the load is applied) is projected onto the plane of the plate or shell. Several methods of projection are available: perpendicular to the surface of the defined contour, along the X, Y, or Z axis of the local coordinate axis, and along a defined vector.
The defined contour does not need to lie in the plane of the plate or shell. The projection direction must be selected in such a way that the projected contour displays on the surface of the plate or shell.
- If the Automatic panel selection in the contour plane option is selected, the following occurs:
- The Direction of contour projection button is no longer available.
- The program automatically detects the panels that lie in the plane of the defined contour and the load is applied to them.
- The contour to which a load is applied. This can be done using the dialog or graphically in the drawing area.
This part of the dialog also lets you open the Contour dialog by clicking
. - If the load is projected, it refers only to definitions in the global coordinate system.
- Optionally, you can specify geometrical limits for the load you are defining.
The Geometrical Limits button is at the bottom of the dialog with a selection option:
- If the selection option cleared, the Geometrical Limits button is not availabe and the limits have no effect on the load.
- When the selection option is selected, the Geometrical Limits button becomes available and the geometrical limits for the selected load type can be defined.