Knowledge Base

Article Number: 47 | VC4 | VC3 | Post Date: November 7, 2017 | Last Updated: June 20, 2018

## Is there an easy way to measure distances, arc lengths, path lengths, and angles?

### 3D Distance Measurements IN Virtual CRASH 4

As of the June 20, 2018 Virtual CRASH 4 auto-update, users can easily measure distances in 3D. Measurements can be made along terrain meshes or along point cloud objects.

Making distance measurements along a terrain mesh is illustrated in the video below. Simply left-click to start creating control vertices and right-click to create the final control vertex and terminate the line. You can then right-click away from the distance tool to access the control vertices or press F3.

Making distance measurements along a point cloud is illustrated below. Note, one must enabled the Snaps Toggle and the "Point Cloud" option in snaps drop down in order for the measuring tool to snap to point cloud data.

### 3D angle Measurements IN Virtual CRASH 4

As of the June 20, 2018 Virtual CRASH 4 auto-update, users can easily measure angles in 3D. The video below illustrates how to measure angles along a surface mesh.

The video below illustrates how to measure angles along a point cloud. Note again, one must enabled the Snaps Toggle and the "Point Cloud" option in snaps drop down in order for the measuring tool to snap to point cloud data.

### ARC and Path Lengths in 2d in virtual crash 4

As of the November 25, 2017 Virtual CRASH 4 auto-update, lines, polylines, curves, and arcs will report their x-y projected lengths in the bottom status window as they are being drawn or modified. Lines and arcs now have a length attribute in the misc menu. This is demonstrated below.

Additional, when the cursor hovers over these objects the length as well as distance from start and distance from end of the path will be displayed.

### 2D Distance measurements in Virtual CRASH 3

For straight lines, the "Dimension Line" tool is the easiest way to measure lengths; however, for VC3, the easiest way to measure arbitrary path lengths is to use the axes tool (note, you can learn more about the axes tool with the Virtual Tutor: help > helpers > axes). The axes tool can then be made to conform to an arbitrary path shape by using the “pick node” feature. In the example below, an arc is drawn, with angular span from 22.026 degrees to 156.316 degrees (angle = 134.29 degrees). The radius is 8.238 ft. The expected arc length therefore is given by $${134.29 \over 360} \times 2\pi \times 8.238 ft = 19.308 ft$$. Once the axis is drawn, simply left-click on “pick node” then left click on the path, and the axes tool’s x-axis will conform to the shape of the path.

You can exactly overlay the axes tool on top of your path by setting the position-local values of the axes tool to the same value as the path.

You can add points to the axes tool. Each point’s (x, y) coordinate is set with respect to the axes tool’s x-axis and y-axis. Here the tool’s x-axis is made to follow the arc shape. Three points are placed in the space of the axes tool. Points are added by simply left-clicking on the “add” button. Each point starts at (0,0), but can then be moved either by changing the x and y coordinate in the left-side control panel, or by left-clicking on the point, holding the mouse button, and dragging the point to the desired location. Here the final point, labeled “to find arc length” was placed at the end of the arc. You will note you cannot drag the point past the end of the path if “pick node” is used. Therefore, we naturally arrive at a measurement of the arc’s length just by reading off the x coordinate for this point. Here we see a value of 19.308 ft, as predicted.

The process is shown in the video below.

### Measuring 2D Angles in Virtual crash 3

Currently, the easiest way to measure angles between objects is to simply draw a line connecting your reference point to your objects. In this case, we set up another axes object so that the origin as our reference point (note the snap to vertex option was used to ensure the line’s start point snapped to the reference point). A line is then drawn from the reference point to the red vehicle. Another line is drawn from the reference point to the blue vehicle. The yaw value in the rotation-local menu for a line is the line’s angle with respect to the global x-axis. So, simply taking the difference between these yaw angles in our example gives the angle between vehicles with respect to the reference point. In this case, the angle between the vehicles is $$51.448~deg – 11.478~deg = 39.97~deg$$.

Tags: Measure length, measure distance, arc length, measure angles, measuring tool, 3d distance, 3d angles, measuring point clouds, measuring surfaces.