Distance from Objects

The Distance from Objects drop-down hosts tools for colouring objects according to their distances from base or reference objects, and analysing them for changes in case of potential failure.

Expand below for detail on each tool.

Distance from Objects compares objects of interest to base (reference) objects and applies colours by the distances between the objects, according to the criteria specified in the colour scheme editor.

Note: The Distance from Objects tool can compare spatial objects of any type.

Colouring by distance is useful for comparing as-built surfaces against design models to highlight non-conformance. You can also use it to identify changes between scans of the same area, such as a slow moving failure in an open-pit mine.

To colour by distance, proceed as follows:

On the Home tab, in the Colour group, click Distance from objects.
Populate the Base object(s) field with at least one reference object.
Select the objects of interest in the project explorer or view window.
From Measurement targets, select one of the following options:
- Closest object to colour object points by distance from the closest base object.
- Average to colour object points by the average distance to all base objects.
From Distance type, select one of the following options:
- Signed to colour by distance and direction from base surfaces. Direction is determined by comparison with facet normals of the base surface. For example, positive distances indicate points are on the same side as facet normals (i.e. in front of the surface).
  
  Note: Signed is only enabled when all objects in the Base object(s) list are surfaces.
- Absolute to colour by the distance only.

From the Measurement Direction drop-down, select one of the following:

	Closest point to colour by the distance to the nearest base point.
	Closest point (vertical component) to colour by only the vertical component of the distance to the nearest base point. That is, .
	Closest point (horizontal component) to colour by only the horizontal component of the distance to the nearest base point. That is, .
	Closest vertical point to colour by the distance to the nearest base point directly above or below the selection point.
	Closest horizontal point to colour by the distance to the nearest base point on the same XY plane (i.e. with the same Z-value) as the selection point.

If you selected either Closest vertical point or Closest horizontal point in the previous step, No measurement colour is enabled. Select a distinctive colour to apply to any selection points for which there are no corresponding base object points.

If you choose Closest vertical point, the No measurement colour is applied to object point 1 because there is no base object point above or below.
If you choose Closest horizontal point, the No measurement colour is applied to object point 2 because there is no base object point on the same horizontal plane.

Adjust the colour scale as required. See Modifying a Colour Scale for detailed instructions.

Tip
To make quick changes to the scale, click Calculate range, enter the required interval settings, then click OK.
Select Create contours to make contours of selected surfaces based on the distances from the base objects.
The contours will be spaced according to the colour band interval. They will be saved in the contours container and loaded into the active view window.

Note: Create contours is only available when you select at least one surface as an object of interest.
Select Create legend to add a legend indicating the colour scale. Double-click on the legend in the project explorer to view it.
Select Create histogram to generate a graph displaying the distribution of data in front of and behind the surface. The chart will be placed in a secondary container called colour by distance from objects legend. Double-click on the container to view the chart.
Select Output distances to file to save a CSV file listing the points of the selected surface and the distances from the base objects. Browse to and enter the Output file name and path.

Click OK or Apply.

A surface coloured by distance from objects (left) and corresponding histogram (right).

Set Acquisition Date

You must set the acquisition date so that the surface change analyser (see Analyse Surface Change below) can establish the relative ages of surfaces being analysed. Proceed as follows:

On the Home tab, in the Colour group, click Set Acquisition Date from the Distance from objects drop-down.
Select the object to which the date is to be applied. It will automatically be added to the Object field.
Set the acquisition date by using one of the following two methods:
- Associate the object with the scan from which it was created. Select Scan, then drag the related scan into the Scan field.
- Set a Date manually. Select Date, then enter the date and time in their respective fields.
  
  Note: The Date field includes a calendar drop-down for convenience.
Click OK or Apply.

The report window will display a confirmation of the acquisition date set.

Analyse Surface Change

The Analyse Surface Change tool enables you to monitor changes in surfaces such as walls, batters, and faces using overlapping surfaces that have been scanned at different times to display the amount and rate of movement.

Important: Before analysing surface change, the surfaces to be analysed must have an acquisition date set, so that the relative ages of the data can be determined.

To analyse surface changes, proceed as follows:

Ensure the surfaces to be analysed have been assigned an acquisition date. See Set Acquisition Date above.
On the Home tab, in the Colour group, click the Distance from objects drop-down.

The Analyse Surface Change panel opens on its Analyse tab.

Expand below for procedures with each tab:

Colour

Note: The Colour tab is enabled only after running an analysis.

Select the Analysed object to be coloured from the drop-down list.

Note: The base object is not included in the list, having the earliest scan date.

Select the Object to measure from as either the object with the Previous date or the Base object.

Select whether to colour the Distance moved or the Velocity of movement.

Select the colour scheme to be used. See Modifying a Colour Scale for detailed instructions.

Tip: Click Reset range to generate a new numeric scale based on the analysis results. You can then edit these numbers to more practical values.

Select or clear the following check boxes per requirements:

Create contours to apply contours to the colour band boundaries. These are saved in the contours container.
Generate legend to create a histogram of the distances between the objects in the colours used to indicate specific distance values. The histogram is saved in a secondary container called Colour by surface change legend.

An example of a surface change analysis