Prism

Directly, interactively create prisms as parametric 3D bodies in space

The cross section of the prism can arbitrarily be defined by the user in the usual way. In principle, the cross section is linked to the axis of the prism at the begin and end with its coordinate origin and extruded over the length thus defined (there is no subdivision of stations).

The axes of prisms are defined by Geometric Positions on the existing 3D model. The Geometric Position 1 defines the start position and the Geometric Position 2 the end position and thus, at the same time, the length and the direction of the prism. In addition, optionally, offsets from GP1 and GP2 can be defined to adjust the start and end position of the prism along its axis. Optionally, the Geometric Position 2 can also be defined directly relative to the Geometric Position 1 by a length + direction.

Subsequently, arbitrary transformations (translations and rotations) can be applied to the prism, whereby the reference coordinate system (defined by GP1 and GP2) persists and the local coordinate system of the prism (always in the origin of the prism) is oriented according to the performed transformation.

For defining the Geometric Positions as well as the direction, there are various options available. In principle, the Geometric Positions can be defined relative to an axis, at a reference point of a structural member or at an already existing prism by docking points (see below).

The following options are available during the interactive definition of a prism in the Property window:

Geometric positions

Reference point

The Geometric Position is placed at the location of user-defined reference point in the cross section of an existing structural member.

Docking point

The Geometric Position is placed at the location of a docking point of an already existing prism.

Per default, docking points are created at the positions of the user-defined reference points in the assigned cross section at the begin, end and in the center of the prism, whereby these positions (and directions) can be adapted afterwards (see Docking points).

Relative Distance

The Geometric Position is defined by a vertical offset relative to the station point of the axis.

Absolute Height

The Geometric Position is defined as an absolute height along the vertical through the station point of the axis.

Relative to GP1

The Geometric Position 2 is defined by a specific distance relative to the Geometric Position 1 in a selectable direction (see below).

Local direction

[Only applicable, if the option Relative to GP1 is selected]

Depending on the selected type of definition, the local direction (local x-direction or longitudinal direction of the prism) is determined by the direction of the axis in the selected station point (or rather reference point) or by the direction of the selected docking point of the existing prism (which can be adapted in the menu Docking points), In relation to this direction, additional automatic transformations (rotations) can be applied.

Longitudinal

Initial orientation in longitudinal direction is kept (no rotation)

Orthogonal (upwards)

Orthogonal orientation in “upward” direction (rotation about 90 degrees about the local z-axis)

Transversal (left)

Orientation in transverse direction to the “left” (rotation about 90 degrees about the local y-axis)

Transversal (right)

Orientation in transverse direction to the “right” (rotation about -90 degrees about the local y-axis)

Offsets

None

The length/position of the prism is defined by the positions or rather distance between the Geometric Position 1 and 2.

Begin & End

The length/position of the prism is defined by the positions or rather distance between GP1 and GP2 plus/minus a pos./neg. offset at the begin and/or end relative to GP1 or GP2, respectively.

Note: The local coordinate system of the prism is thereby set to the start point of the prism. The reference coordinate system remains at the Geometric Position 1. Further, it has to be noted that the offsets are applied before the (automatic or defined) transformation (i.e. the offsets change the start point of the prism and thus the reference point for a transformation related to the local coordinate system).

To generate a new prism

1. Click Prism.
2. Optionally, edit the name and the description and confirm the input with OK.

   A new prism is created in the menu Bodies in the project navigation tree.

3. Select the cross section which you want to assign to the prism by clicking it in the menu Cross Sections in the navigation tree or via the drop-down menu in the Property window.
4. Define the position of the wished start position of the axis of the prism (Geometric Position 1) in the 3D model in the View window.

   Note: Select the wished type of definition (Reference point / Docking point / Relative distance / Absolute height) in the Property window - see explanations above.

   In case of the types of definition Relative distance and Absolute height, analogously proceed as described e.g. in Pier relative to axis in the steps 3 - 5.

5. Define the position of the wished end position of the axis of the prism (Geometric Position 2) in the 3D model in the View window.

   Note: Select the wished type of definition (Reference point / Docking point / Relative distance / Absolute height / Relative to GP1) in the Property window - see explanations above.

   In case of the types of definition Relative distance and Absolute height, analogously proceed as described e.g. in Pier relative to axis in the steps 3 - 5.

   In case of the type of definition Relative to GP1, additionally select the wished direction in the property window (see explanations above) and then define the wished length of the prism related to the Geometric Position 1 along the selected direction in the 3D window.

6. Optionally, define an offset at the begin and/or end.

   Thereby, analogously proceed as described in Link girder in step 5.

After creating the prism, there are available numerous tools for editing and modifying via its context menu (marking in the 3D View window).

Use the Property window to edit all performed inputs. Additionally, you can adjust the position/orientation of the prism there.

Position/Orientation (Property window)

Position and orientate the prism

Orthogonal type

Only applicable in the case that the Geometric Position 1 of the prism was defined by a reference point (exception: ORTHO_YG is also applicable for docking points). The coordinate system of the prism can be oriented related to the coordinate system of the cross section assigned in the station point of the structural member at the position of the selected reference point as follows:

• ORTHO: no modification of the orientation (an orthogonal coordinate system is presumed): X remains in the direction of the axis, Y and Z remain oriented according to the cross section of the structural member
• ORTHO_XZ: Default setting, X remains in the direction of the axis, Z is projected into the normal plane to X, and Y is oriented orthogonally to the XZ-plane
• ORTHO_XY: X remains in the direction of the axis, Y is projected into the normal plane to X, and Z is oriented orthogonally to the XY-plane
• ORTHO_ZY: Z remains in the direction of the Z-axis of the cross section of the structural member, Y is projected into the normal plane to Z, and X is oriented orthogonally to the YZ-plane (in other words: X orthogonally to the cross section plane of the structural member, Y and Z according to the cross section of the structural member)
• ORHTO_YG: X is oriented along the global Y-direction, Z is projected into the ground plane, and Y is oriented orthogonally to the XZ-plane (global vertical orientation)

Docking point

Position the prism by selecting a defined docking point of the prism to be placed at the Geometric Position 1.

Note: This tool is also interactively available via the context menu of the prism (see Change reference origin).

Invert direction

Invert the direction of the axis of the prism (rotate by 180 degrees about GP1).

Cross section (Property window)

All variables defined in the cross section are displayed with their values defined there.

By activating the checkbox the values of the variables can be modified for the individual cross section assigned to the prism directly via the Property window. (That means that the same cross section assigned to another member remains unaffected and individual values can be assigned to its variables).

By deactivating the checkbox, the value of the variable is reset to its value defined in the cross section.