Surface bodies are areas that can be meshed to create diffracting or non-diffracting elements for the Aqwa analysis. The name of the surface body will be obtained from that given in DesignModeler/SpaceClaim Direct Modeler.

If a body is not required for the analysis it can be suppressed (Body Activity). Suppressed bodies will not be meshed and will be excluded from the analysis. You can hide the body in the graphic window (Body Visibility), in which case it will not be shown but will be included in the analysis. By default, each surface body inherits its color from the parent part. You can override this behavior by changing Body Color Definition to Manual Definition, which allows you to set the Body Color manually.

It is possible to change the type of surface from a Physical Geometry to an Abstract Geometry (Structure Type). For physical geometry, Program Controlled Surface Type will set all surface bodies below the water surface as diffracting and those above will be non-diffracting. If required, those below the water surface can be manually defined as non-diffracting elements for the analysis. This may be required, for instance, when part of the structure is in contact with the sea bed, or where contact occurs underwater between adjacent parts.

For an abstract geometry, Abstract Type provides a number of options to select how this geometry is to be used. If an area is of particular interest, then the Field Point Positions option enables a mesh to be applied and each node of the mesh will form a field point element; additional information will be available at these points. Alternatively, Internal Lid and External Lid can be used to suppress standing waves either between structures or within structures.

If the generation of an external lid is specified, two additional parameters are required. The first is a Lid Damping Factor, set between 0 and 1. The factor represents how effective the lid is to be; 0 will result in no effect, while 1 will prevent any vertical water surface velocity under the lid.

The second parameter is the Gap for Lid. It is a representative size for the lid; typically the distance between the two vessels or the width of a moon-pool. It enables the lid properties to be tuned to the resonant frequency of waves in the gap.