Surface

Source file: create-surface-group.htm

The Surface group tools of the Create tab enable you to create surfaces from scans and point selections by various methods that are suited to different situations.

	Topographic Surface (`Alt`+`2`) Create a surface from a plan view perspective.
	Scan Surface (`Alt`+`N`) Create a surface from a connected points selection (see Scan).
	Spherical surface (`Alt`+`I`) Create a surface from a spherical reference grid.
	Complex 3D Surface Create a surface modelling complex areas.
	Poisson Surface Create closed solid surfaces.
	Combination Surface Merge selected surfaces into one.
	Extrusion (`Alt`+`X`) extrude surfaces from lines or shapes.
	Offset Surface create a surface offset from a selected object.
	Fusion Surface (`Alt`+`Y`) Fuse multiple surfaces, retaining the most detailed where they overlap.

Topographic Surface

The Topographic Surface tool (Alt+2) enables you to create a surface from a scan, or a group of scans or surfaces from polygons.

This tool works in the XY plane. That is, it triangulates straight down. This means that if there are areas of undercut walls, these will not be modelled accurately; in this case, use the spherical surface tool. See Spherical Surface.

Run this tool after scans have been appropriately registered and filtered. See Position and Filter.

To create a topographic surface:
1. On the Create tab, in the Surface group, click Topographic Surface.
2. Select Trim large triangles to eliminate long, incorrectly generated triangles. Enter Maximum edge length to define the maximum size of triangles being created. Select Boundary edges only to restrict trimming to large boundary triangles.
3. Select an Output triangulation surface type by selecting one of the following:
4. Ensure the scan data is highlighted in the project explorer.
5. Click OK.

Note: Once the surface has been created, it may require despiking. See Despike.

A topographic surface of a pit relimited to a polygon.

Scan Surface

The Scan Surface tool (Alt+N) enables you to create a surface from a single scan, based on point connections made with the connection tools in the Scan group of the Position and Filter tab. This can be helpful for modelling irregular shapes such as truck trays and loader buckets.

To create a scan surface:
1. Using Connect or Smart Connect, connect the points in the scan you want the surface created from.
  
  Tip: Because the smart connect, connect and disconnect tools act on point selections, you can edit connections manually if necessary.
2. On the Create tab, in the Surface group, click Scan Surface.
3. Select the connected scan created with Connect or Smart connect to triangulate.
4. Click OK or Apply.

The surface is saved in the surfaces container by default. You can change the container in the Destination field.

Spherical Surface

The Spherical Surface tool (Alt+I) enables you to create a surface based on a spherical grid instead of the XY plane. This is particularly useful for modelling overhanging surfaces.

Run this tool after scans have been appropriately registered and filtered. See Position and Filter.

To create a spherical surface, follow these steps:

With the scan loaded in a view window, press P to put it in Plan View Mode.
Select the scan data in the project explorer.
On the Create tab, in the Surface group, click Spherical Surface.
Select the required Spherical type from Surface or Closed solid.
Enter coordinates or click in the view window to define the Spherical origin point. This is the centre point for the spherical grid.
If you chose Surface at step 4, enter a value or click in the view window to select the Look point. This defines the radius of the spherical grid.

The origin and look point are displayed in the view window.

Note: If you are modelling only one scan, the spherical origin and look points are initially set to the origin of the scan and backsight direction by default.
Note
The spherical surface tool will display transient geometry, depending on the selected Spherical type.
- Surface will show a red arrow from the origin to the look point and arc behind the arrow, with a radius equal to the arrow’s length centred on the origin. This is useful at step 8.
- Closed solid will show a sphere of a fixed size, which can be ignored.
Press Z to put the view in Z Up Mode, then rotate the view so that it is side on.
Alter the Z value of the Spherical origin point so that the red arrow is perpendicular to the wall.

Tip: Copy the Look point Z coordinate.
Select Trim long triangles and enter a Maximum edge length if you want to avoid long, incorrectly generated triangles.
Select Split surface along edge constraints if you want to split the surface into separate objects, by any lines or polygons selected in the project explorer when the surface is created. This option can be of use as a 'cookie cutter' when producing windows or a mine portal.
Click OK.

The surface is saved in the surfaces container by default.

Note: Once the surface has been created, it may require despiking. See Despike.


A topographic surface (left) and a spherical surface (right).

Complex 3D Surface

The Complex 3D surface tool provides a simple solution for creating surfaces from point clouds where the existing methods do not adequately model the nuances of the actual ground or surface. The method only requires input of a guide to the smallest feature size, with which it will build the surface based on points within proximity of each other, regardless of orientation. This approach is good for detecting and including even small indents, overhangs and caves or holes that other surfacing methods would miss, and for modelling complex underground areas which include a number of pillars or interconnected tunnels.

To create a complex 3D surface, do the following:
1. On the Create tab, in the Surface group, click Complex 3D Surface.
  
  The Complex 3D Surface tool panel will open.
2. Set the desired Feature Size.
  
  Note: Holes can occur in the model if the feature size guide is so small that the procedure cannot find a neighbouring point close enough to connect to. Larger feature sizes will result in fewer holes in the surface, but may also result in spike artefacts and less detail representing the true shape of the stope or ground.
  
  Tip: Use a feature size that is a little larger than the holes you want to fill, but a little smaller than the size of features you want to keep.
3. Select Smoothed surface to minimise spikiness in the resulting surface.
  
  Note: If surface smoothing is used for a large feature size, there will be less detail in the resulting surface.
4. Click OK or Apply.
  
  A surface called Triangulation of <object name> or Smoothed triangulation of <object name> is created in the surfaces container.
  
  Note: Where surfaces are created from multiple objects, they are named either Triangulation or Smoothed triangulation.
5. Inspect the new surface in a view window and decide whether to run again with different parameters.
  
  Tip: Run the tool once with Smoothed surface cleared, and again with Smoothed surface selected, then compare the two results.
6. Click Cancel or when finished.

A Complex 3D surface

Poisson Surface

Source file: create-surface-group.htm

The Poisson Surface tool uses the Poisson technique to create closed solids of underground voids.

The Poisson Surface tool has the following advantages:

Is resilient to noisy data and misregistered artefacts.
Performs quick calculating and rendering processes.
Predicts where missing scan points should be and fills in those voids.
Detects any extra unwanted points and ignores them for the surface reconstruction.

To create a Poisson surface, follow this procedure:
1. On the Labs tab, in the Create group, click Poisson Surface.
2. Under Output triangulation choose how to surface your selection. Select from:
  - Single surface
  - Single surface per object
3. Under Point Normals, in the Nearest neighbour count field, enter the number of nearest neighbouring points to use for the surfacing calculations.
  - A larger count will make the surface smooth out more but you'll potentially lose sharpness around complex features.
  - A lower count will make the surface appearance coarser.
4. Under Surface you can configure the parameters that affect the resulting surface creation.
  - Depth will determine the triangulation size used.
    - Lower values are sufficient for smooth surfaces with minimal noise.
    - Higher values manage noise better, for a more consistent surface.
  - Scale defines the maximum feature size the tool will process.
    - Increasing Scale will cover larger gaps and will completely close the ends of a tunnel, creating a closed solid. If Scale is too high it will increase the base triangle size of the surface it's creating, resulting in larger bulges at the ends of tunnels. This can cause it to lose some resolution on the walls.
    - Decreasing Scale might only triangulate the walls. If Scale is too small, the algorithm might not even triangulate all the walls.
    - Select Use linear fit if the surface reconstruction is to use linear interpolation to estimate the positions of the iso-vertices.
5. Click OK or Apply.

In the above example, the scan (left) had all its voids (black areas) completely filled in (right) by using the Poisson surface tool. The details are preserved and edges are smoothed out.

Combination Surface

The combination surface tool enables you to merge selected surfaces into one single surface or closed solid.

To create a combination surface:
1. On the Create tab, in the Surface group, click Combination Surface.
2. Select the required Surface type option from the following and use the relevant procedure below:
  - Topographic: Creates new surfaces or closed solids based on different ways of combining the original topographic surfaces
  - Closed solid: Creates new closed solids or volumes, based on different ways of combining the original closed solids.
  - Solid and topography: Creates new closed solids or volumes by trimming a closed solid with a topography. You can choose to retain the portion above or below the topography, or both.

Expand below for further instructions, per your selection.

Topographic

Select or clear Collapse vertical facets as required. If selected, choose a Collapse direction.

See step 3 of Fix Surface.
Select the required Combination type from the drop-down list.
- Lowest: combines the lowest parts of all surfaces.
- Replacement: replaces parts of the largest surface with smaller surfaces.
- Highest: combines the highest parts of all surfaces.
- Intersection solid: creates a closed solid between the highest and lowest points of the two intersecting surfaces.
Select Keep rasters to preserve the image or raster that is associated with the surface.
Select or clear Display result in new view as required.
Click OK or Apply.

A new surface is created and stored in the surfaces container.

Extrusion

The Extrusion tool (Alt+X) enables you to create extrusions from objects such as polygons, lines, circles and more. This can be helpful, for example, for creating a surface from a line, or a cylinder from a circle.

To create an extrusion:

On the Create tab, in the Surface group, click Extrusion.
Select the object from which to create the extrusion.

Set the Direction of the extrusion by selecting one of the following options from the drop-down list and specifying its criteria:

	Two points Define the direction and distance by specifying two points.
	Two points and distance Define the direction by specifying two points, then enter the distance.
	Facet and distance Make the direction perpendicular to a selected facet, then enter the distance.
	Axis aligned and distance Define the direction by an axis of the view window, then enter the distance.
	Bearing, inclination and distance Define the direction by a bearing and inclination angles, then enter the distance.
	Action plane axis and distance Define the direction by an axis of the action plane, then enter the distance.

You can populate parameter fields either by manually entering values, or selecting data in the project explorer or view window.

If the extrusion must be terminated by an intersecting plane, rather than by a defined distance, select Intersection plane and put the action plane in the required position.

Note: Intersection plane overrides the distance field.
Click OK or Apply. The extrusion will be saved in the cad container.


An extrusion created from a circle.	An extrusion created from a polygon and extruded to a plane.

Offset Surface

The Offset Surface tool enables you to create a facet network at a fixed distance from the selected object. This can be helpful for CAD modelling of data.

You can make an offset surface from points, lines, loops or surfaces.

To make an offset surface:
1. On the Create tab, in the Surface group, click Offset Surface.
2. Enter the Offset distance for the surface.
3. Select a Coarse or Smooth surface. Smooth surfaces contain more triangles and will take longer to create.
4. The offset surface is saved in the surfaces container by default. You can change this in the Offset surface field.
5. Click OK or Apply to create the surface.

An offset surface created from a plane; the offset surface is displayed as wireframe.

Fusion Surface

The Fusion Surface tool (Alt+Y) allows you to create a new surface of evenly sized triangles by following the original surfaces. Where surfaces overlap, the fusion surface will follow the most detailed surface. Fusion surfaces help to accurately model complex shapes or undercut faces in 3D.

To create a fusion surface, do the following:
1. Select the surfaces to be fused in the project explorer.
2. On the Create tab, in the Surface group, click Fusion Surface.
3. Enter the Triangle size. All triangles produced will be this size.
4. Click on a point to start the fusion. This should be somewhere central with good overlap between the surfaces.
5. Select or clear Apply photographs as appropriate.
6. Click OK or Apply.
  
  A progress indicator displays, showing the fusion progress.
7. Click Preview partial surface to display the surface as it is created.

Note: If the triangle size is too small, it can result in intersecting triangles. Always check with the surface validity tool afterwards. See Surface Validity.


Result of keeping the top portion of the solid (left) and the bottom portion of the solid (right).