A Hull is a created boundary that envelopes around all your drawn survey geometries. You typically use the Hull tool in order to generate a boundary that confines your Project Data within a border; you can then triangulate the selected geometries as a surface. You can hull a selection of drawn geometries or hull all geometries that are visible in the Viewport using the same Hull button, as it changes dynamically between Hull Selection and Hull All depending on whether you have selected geometries or not. 


Overview


How Hull Works

The Hull tool creates a hull around the geometries based on what is drawn on the terrain along with what parameters you give the tool to work with. You can Hull all the visible geometries in the Viewport using Hull All, or you can select the drawn geometries you want to create a boundary around using Hull Selection. There are multiple scenarios that can change how the Hull tool envelopes your drawn geometries: Hull All, Hull Selection, Hull with Breaklines, and by using the Concave Hull Sharpness parameters.


Hull All

The standard hull function is to create a boundary around all the visible drawn geometries to help organize and contain your survey. Simply click Hull All to create a standard boundary around the drawn geometries.

Using Hull All to generate a standard boundary around your drawn geometries.


Hull Selection

You can select any portion of drawn geometries in your survey and create a boundary around that selection. Simply highlight the geometries you want to segregate from the rest and click Hull Selection.

Use Hull Selection to generate a boundary around geometry items you have specifically selected.


Concave Hull

The Concave option allows you to 'shrink wrap' a hull around your drawn geometries. You can set the Sharpness of the Hull to concave inward between levels 1-10, 1 being the most relaxed, and 10 being the tightest hull around the geometries.

Using Concave Hull with different levels of Sharpness (between 1-10) to create the kind of border you want around your survey.


Concave Hull comparison with sharpness set at 1, 5, and 10, respectively

Concave Hull with Sharpness set to 1

Concave Hull with Sharpness set to 5

Concave Hull with Sharpness set to 10


Hull with Breaklines

When you create a Hull around geometries with a breakline on the outermost edge, the Hull will match your breakline and create a hull around any other outer geometries by connecting them with the parameters you set. This is designed to make it easier to generate a surface that stays within your preferred area. 

Using Hull All with breaklines to have the boundary conform to the outer breaklines.


Why is Hulling Useful?

The Hull tool is useful when you need to triangulate your geometries and keep them confined with the survey without needing to remove the triangle edges manually.


Confine your triangulation. If you use Triangulate All when creating a surface for your survey, it can sometimes create a lot of unnecessary edges around the TIN that need to be removed. To avoid extra edges on your surface, you can hull your entire project with one click and save time from needing to do further edits by using the Hull All tool.

Use the Hull tool to confine the edges of your triangle to just the survey.


Clip your ortho/DSM. You can also use Hull to clip your ortho/DSM to make a nice-looking map with clean edges around the survey.

Use Hull around your drawn geometries to create a nice-looking map around the survey with clean edges.


Tips and Tricks

Densify your hull. Before creating your triangulation, you can densify your hull, which ensures that topographic detail along the boundary is captured, helping the resulting surface align more accurately with the terrain.

  • Mine - Use breaklines and a densified hull to complete your surface.
  • Vegetated area - Use hull and densify it around a low-pass point grid to capture the topography accurately around a tighter boundary.


Manually edit the hull. You can always manually edit the hull using Edit Vertex after it is generated.


Section lines. When generating section lines, a hull is automatically created. You can use it to avoid unnecessary edges on your triangulation.