Turbine data: Drawing

Draw hub, hub pen

These data determine whether or not the hub is drawn, and specify the pen that is used to draw it.

Draw blades, blade pen

Determine whether or not the blades are drawn, and specify their pen.

Node axes colours

Blade node structural frame axes $(x, y, z)$ can be drawn in different colours. This can help you to identify the $x$ and $y$ directions in particular, and may be useful in interpreting the results for different component directions. The drawing, or not, of the node axes themselves is controlled by the node axes preference.

Draw tower, tower pen

Determine whether or not the tower is drawn, and specify the pen that is used to draw it.

Shaded drawing

By default, for shaded 3D views, turbines are drawn as solid objects based on their hub radius and blade geometry. The hub is drawn as a circular cylinder, the blade segments as elliptic cylinders.

Alternatively the object can be represented by an imported 3D model by specifying the shaded drawing file. This can be one of the following formats:

If you use a relative path then the path will be taken as relative to the folder containing the OrcaFlex file.

Draw size (.x, .obj) allows you to scale the drawing. All directions are scaled equally such that the longest side in the drawing is drawn to the given draw size. This longest side is calculated by fitting the smallest possible cuboid around the vertices of the shaded drawing, aligned with the shaded drawing's local axes. The longest side is the length of the longest side of this cuboid.

Set draw size to '~' to display the drawing using the absolute coordinates as specified in the drawing file.

Note: If you use a value of '~' for draw size, then OrcaFlex uses the coordinates in the drawing file directly, taking them to be in the prevailing OrcaFlex units. If these coordinates use a different length unit from your OrcaFlex model, then you should define them in an auxiliary file called AdditionalInformation.txt. Examples of this can be found in the sample shaded drawings provided by Orcina.

The culling mode (.x, .obj) option enables an optimisation that may provide a useful performance benefit. When enabled, only faces towards the viewer are drawn. The backward-facing faces are culled – they are not drawn. By culling these faces, less computation is required and performance is improved. In practice however, typical modern graphics cards are sufficiently powerful that you may not notice any benefit.

There are different conventions in common use regarding the specification of the outward facing direction, which we refer to as clockwise or anticlockwise. It is not always possible to detect programmatically which convention is in use, so we must pass the responsibility to you, the user, to do so. It is usually immediately apparent by trial and error which option is correct.

Culling requires that the faces defined in the drawing file have their outward-facing directions defined correctly. If this is not the case, then the object will not display correctly; typically, sections of the the object will be missing when it is drawn by OrcaFlex. This problem is usually resolved by disabling culling.

The mirror in plane (.x, .obj) option allows you to mirror the whole 3D model about the specified plane. Note that the axes refer to the 3D drawing axes rather than the OrcaFlex axes. This may be required if the original drawing axes convention does not match that assumed by OrcaFlex.

These assumptions may not be appropriate for your mesh file, so this option allows you to adjust the rendering so the model appears correctly. When you choose to mirror in a plane, this has the effect of switching from a left-handed axis convention to a right-handed axis convention, and vice versa.

A common sign that the coordinate convention needs switching is if asymmetric features, or text on the model, appear mirrored in the shaded view.

For panel mesh files you must specify the mesh length units and the mesh symmetry. OrcaFlex uses length units to scale the mesh panels to match the units system of the OrcaFlex model. Mesh symmetry can be one of the following values: none, xz plane, yz plane or xz and yz planes. This is used to generate the additional panels that are implied by the symmetry.

For panel mesh files that support multiple bodies or structures, you must specify the body number to be imported. If the panel mesh file format does not support multiple bodies then this value is ignored.

For panel mesh files that define panels above the waterline (dry panels), you must specify whether to import dry panels. If the panel mesh file format does not support dry panels then this value is ignored.

Shaded drawing origin is provided because the shaded drawing and the turbine may have different origins. The shaded drawing origin defines the origin of the shaded drawing with respect to the turbine's local axis system. Similarly shaded drawing orientation allows you to reorient the shaded drawing to match the turbine's axis system. The 3D model rotates with the main rotor shaft.

Note: The 3D model is drawn in addition to the default hub and blade drawing. Typically you would suppress one or both of these by unchecking draw hub or draw blades. For example, you might allow default drawing of the blades, but suppress default drawing of the hub and replace it with a more realistic 3D model.