Wire frame drawing
Objects are drawn as a series of connected lines – a wire frame – with the pen colour, line width and style (solid, dashed etc.) defined by the object's drawing data. You can change the pen colours etc. for an object at any time by editing the drawing data for that object. To change the pen colour, click the colour button on the data form and select the new colour.
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In Windows, a line width of zero does not mean "do not draw" – it means draw with the minimum line width. To suppress drawing either set the line style to be clear or else hide the object. |
In a wire frame view, the various specific objects are drawn as follows.
- The various coordinate systems can be drawn as small triplets of lines showing their origin and the orientation of their axes. The wave, current and wind directions can be drawn as arrows in the top right-hand corner of 3D views. You can control both what is drawn and the drawing data used.
- The seabed is drawn as a grid using the seabed pen.
- The sea surface is drawn as a grid or as a single line. This is controlled by the user's choice of surface type specified on the drawing page on the environment data form. If the type is set to single line then one line is drawn, aligned in the primary wave direction (that of the first wave train). If the type is set to grid then a grid of lines is drawn, aligned with the primary wave direction. This line or grid is drawn using the sea surface pen.
- Shapes are drawn either as wire frames (blocks, cylinders and curved plates) or as a grid (planes). As well as controlling the pen colour, width and style, you can also control the number of lines used to draw a shape.
- Vessels are drawn as a wire frame of edges and vertices defined on the vessel and vessel types data forms.
- 3D buoys are drawn as a single vertical line of length equal to the height of the buoy.
- 6D buoys are drawn as a wire frame of edges and vertices. Spar buoys and towed fish are represented by a stack of cylinders and are drawn accordingly, with a choice of square or circular cylinders. Lumped buoys have no defined geometry, so the vertices and edges or panels are explicitly user-defined on the buoy data form.
- 6D buoy wings are drawn as rectangles in either the 6D buoy pen or the wing type pen as determined by the wing type data.
- Lines are drawn as a series of straight lines, one for each segment, joining points drawn at each node. Separate pens are used for the segments and nodes, so you can, for example, increase the pen width used for the nodes to make them more visible. There is also, on the line data form, a choice of which pen to use to draw the segments.
- Clumps are drawn as a thin vertical bar.
- Drag chains are drawn using the colour and line style specified on the attachment types form. The hanging part of the chain is drawn as a line, of length equal to the hanging length and at the angle calculated using the above theory. The supported part of the chain (if any is supported) is separately drawn as a blob at the seabed, directly beneath the node. The drag chain drawing therefore directly reflects the way in which the chain is modelled.
- Flex joints are drawn as a circular blob using the colour and line style specified on the attachment types form.
- Links and winches are drawn as straight line segments joining the connection points.
- Constraints are drawn as a pair of axes representing the in-frame and the out-frame, using the colour and line style specified on the constraint data form. The axis labels are drawn in user-specified colours which indicate whether individual degrees of freedom are free, fixed or imposed. If appropriate, then the coordinate mapping associated with a curvilinear constraint is drawn as a series of straight line segments representing the gridlines of the mapping.
- Support cylinders are drawn as a straight line. The cylinder length is defined by the support type. Optionally the support cylinder ends can be drawn as circles with the support type diameter.
- Morison elements are drawn as a straight line, with length defined by the element data.
- Full field wind is drawn as a 2D grid using the wind pen, representing a slice, in the vertical $yz$ plane, of the full 3D wind field at the wind origin. Optionally, the wind field can also be drawn as arrows, representing the wind vectors on a series of user-specified $yz$ planes. The size, and colour, of these arrows is determined by the wind speed at each position and the vector field scale.
- Line covered sections are not fully-fledged physical objects in the model; instead, the height of the cover is defined on a per arc length basis when the line is at some datum, as-buried, position. The covering material has no lateral extent and so cannot be drawn as a 3-dimensional object. Instead, it is drawn as a curve in the same vertical plane as the line (which moves horizontally with the line), to be interpreted as a rough representation of how close the line is to exiting the top of the cover. To make the drawing easier to visualise, the covered section is shown to form a closed loop down to, and along, the seabed. This is for cosmetic purposes only, and you should not necessarily read any physical significance into it.
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Covered sections are only drawn in the wire frame view. The pen used for the drawing is determined by the cover type associated with the covered section. |
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Any covered section for which the cover height has been set to N/A will not be drawn. |
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Since the drawing does not take into account deformations of the seabed in the presence of the line, it is technically possible (although extremely unlikely) for the top of the cover to be defined beneath the seabed (as drawn in the 3D view). OrcaFlex ignores this for purposes of the drawing: the top of the cover will never drawn below the seabed. |
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Cover types with multiple layers can also be drawn. |
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Some nodes can be buried under under multiple covered sections simultaneously. Each covered section will be drawn separately in this case. |
Connections
All OrcaFlex model objects can be connected to other objects, and we use the terminology that a child object is connected to a parent object. To denote the possible connection points on child objects in a wire frame drawing, we draw them as the following small shapes:
- On a line or a link, end A is drawn as a triangle, end B as a circle. Mid-line connections are drawn as squares.
- Similarly for a winch, the first connection is drawn as a triangle, the last as a circle, and the others as squares.
- For all other objects, we draw triangles.
Their colour is determined by the nature of the connection:
- If the connection is made to a parent object, it is drawn in the colour of the parent object.
- A fixed connection is drawn in the colour of the global axes.
- An anchored connection is drawn in the seabed colour.
Shaded drawing
For shaded views the various objects are drawn as follows:
- View axes and global axes are drawn as small triplets of lines showing their origin and the orientation of their axes. The wave, current and wind directions can be drawn as arrows in the top right-hand corner of 3D views. You can control both what is drawn and the drawing data used.
- The sea surface and seabed are drawn as textured surfaces using their respective pen colours. Both surfaces can be drawn with user-specified levels of translucency.
- Shapes are drawn as solid objects and planes allow for user-specified levels of translucency. Alternatively shapes can be represented by an imported 3D model.
- Vessels are drawn as a solid, filled-in shape based on the wire frame data. Alternatively vessels can be represented by an imported 3D model.
- 3D buoys and clumps are drawn as an ellipsoid with the specified volume and height.
- Lumped 6D buoys are drawn as a solid, filled-in shape based on their wire frame data. Spar buoys and towed fish are drawn as solid objects using the specified cylinder geometry. Alternatively 6D buoys can be represented by an imported 3D model.
- 6D buoy wings are drawn as plates using their specified span and chord. Alternatively they can be represented by an imported 3D model.
- Lines are drawn as a series of cylinders, one for each segment using the outer contact diameter as specified on the line type data form. There is also, on the line data form, a choice of which pen to use to draw the segments.
- Drag chains are drawn as a chain with bar diameter derived from the drag chain's effective diameter.
- Flex joints are drawn as cylinders with radius $2R$ and length $4R$ where $R$ is the radius of the node to which the flex joint is attached.
- Links and winches are drawn as a series of cylinders joining the connection points. The diameter of the cylinders can be specified on the object's data form. Intermediate winch connections points are (optionally) drawn as spheres.
- Constraints are drawn as a pair of axes representing the in-frame and the out-frame, using the colour and line style specified on the constraint data form. The axis labels are drawn in user-specified colours which indicate whether individual degrees of freedom are free, fixed or imposed. If appropriate, then the coordinate mapping associated with a curvilinear constraint is drawn as a series of cylinders representing the gridlines of the mapping. The diameter of the cylinders can be specified on the constraint's data form.
- Support cylinders are drawn as cylinders with length and diameter defined by the support type.
- Morison elements are drawn as a cylinders, with length defined by the element data and diameter defined by the shaded drawing diameter of the element type. If a value of ~ is specified then the diameter is taken to be the normal drag diameter.
- Full field wind can optionally be drawn as arrows, representing the wind vectors on a series of user-specified $yz$ planes. The size, and colour, of these arrows is determined by the wind speed at each position and the vector field scale.
- Line covered sections are not drawn in the shaded drawing view.
Hiding objects
You can choose, in the model browser and on the all objects data form, to hide objects, in which case they are not drawn in any wire frame or shaded views. Note that this does not exclude them from the OrcaFlex calculation: they have the same effect on the model, whether they are drawn or not.
