Wireframe Hull to Strings

To access this dialog:

Activate the Surfaces ribbon and select Plane | Hull to Strings
Run the command convert-wf-hull

Creates strings from the hull (outline) of an existing wireframe object or selected triangles. The orientation of the plane to be used to create the cross-sectional string object is fully-configurable.

You can either output a string that lines up with the selected plane (a "2D" boundary), or you can output a string object representing the elevation of the boundary of each point of the object (a "3D" boundary), for example, in the image below, the same topography wireframe surface has been converted to a hull string. The orange string represents the output of a horizontal projection with the Use elevation check box disabled, whilst the purple line shows the default setting, that is, projecting the boundary line to the currently active section:

This command runs the convert-wf-hull command.

Due to the complex nature of this command, certain arrangements of wireframe structure can pose numerical tolerance problems when a wireframe object has not been properly 'preconditioned'. This may result in less than perfect results, but the good news is there are a couple of easy things you can do in these cases to resolve the situation:

Use your boolean tolerance (Wireframe Settings). This set of options can be utilized to choose how close strings points can be before they are snapped together. If you have a problem with many individual segments, you can try increasing the boolean tolerance before running the command. The actual setting will be determined by the overall structure of your data set, so experiment to find the best results.
On occasion, when there are many faces perpendicular (or almost perpendicular) to the plane, this command may deliver unexpected results. The presence of these faces can make it very difficult to work out what constitutes an 'outside' edge, and may result in some gaps in the resulting string. In these cases, a small adjustment to the rotation of the plane (e.g. changing the Inclination from 90 to 89.5) is often enough to resolve the ambiguity in the calculations involved and allow a more integral string object to be created.

The string segments generated are planar and are generated at the average "depth" of the wireframe that is being hulled. Thus the orientation of the view plane affects the hull created but not the position.

Note: This command supports flexible wireframe selection.

Running the Hull to Strings command

Ensure at least one wireframe object has been loaded.
Run the Hull to Strings command to display the associated dialog.
Select the relevant wireframe object, using the Object drop-down list (or, alternatively, select wireframe triangles (which can be in any object or objects) and choose the Selected triangles option.
Specify the centre point of the plane (the Plane Reference Point) that will be used to bisect the wireframe object to create a cross-sectional string.
Determine a basic orientation for the bisection plane (either Horizontally, in a North-South direction or in an East-West direction through the defined Plane Reference Point. You can also set an Azimuth and Inclination manually to achieve a particular plane orientation, or you can choose any loaded VR Section.
Alternatively, rather than defining a plane, you can either use the current viewplane (Use View Plane) to bisect your wireframe data or select any wireframe face (a triangle), selected or otherwise, on screen that will be used as a basis for creating a bisection plane.
Choose if you wish to output a boundary string that aligns with the current section (Use elevation disabled) or a boundary that follows the 3D 'elevation' of the target object (Use elevation enabled),
If you only want the outermost boundary to be created (this could avoid creating closed strings around internal voids, for example) you can select the Outer boundary only option. If left unselected, strings will be generated at all intersections of the input wireframe data and the defined plane.
Choose if you wish to generate data in the current strings object or another (or new - just type a new object name) string object.
Click OK to generate data based on the settings supplied.

Field Details:

Wireframe: choose either:

Object: displays the name of the current wireframe object. The selected wireframe may be changed using either the drop-down list.
Selected triangles: select this option to generate a hull string around preselected wireframe triangle data. You can select this data whilst the Hull to Strings dialog is still open if you wish, or it can be selected before running the command.

Plane Orientation: provides the tools for defining the orientation of the plane against which the wireframe object will be split.

Horizontal: sets the plane to horizontal (i.e. both azimuth and dip are 0 degrees).
North-South: sets the plane to a vertical North-South orientation (i.e. azimuth is 90 degrees and dip is -90 degrees).
East-West: sets the plane to a vertical East-West orientation (i.e. azimuth is 0 degrees and dip is -90 degrees).
VR Section: if any sections have been defined in the 3D window, these planes can be used to generate strings from the hull of the selected wireframe object. Click this button to transfer the azimuth and dip of the section to the relevant fields. If no section data has been defined, this option will be unavailable.
Azimuth: sets the azimuth of the plane. Note that this field is automatically updated when either of the top four options are selected.
Inclination: sets Inclination of the plane. Note that this field is automatically updated when either of the top four options are selected.

Plane Reference Point: identifies a single point which will fix the plane in space.

X: displays or sets the X coordinate (easting) of the reference point.
Y: displays or sets the Y coordinate (northing) of the reference point.
Z: displays or sets the Z coordinate (elevation) of the reference point.

Use View Plane: fixes the plane as the current view plane in the design window.

Pick Face: activates the picking tool to allow the selection of a wireframe face. The azimuth and dip will correspond to those of the face and the reference point will have the coordinates of the selected point.

String Output:

Use elevation: choose if you wish to output a boundary string that aligns with the current section (Use elevation disabled) or a boundary that follows the 3D 'elevation' of the target object (Use elevation enabled),
Outer boundary only: disabled by default (meaning string data will be created at all intersections of the input wireframe with the defined section), you can select this check box to ensure only the outermost closed boundary is created. This can be useful, for example, if you wish to capture the exterior boundary of a topography without any internal voids created by low elevation values intersecting a plan section.
Current object: choose to output your hull string data to the current object, another existing string object (expand the list) or a new one (type a new name).