Measurement Probe Kit Guide

Main page

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Scope

This page provides information and instructions on how to utilize the Probe Measurement Kit.

Overview

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Measurement probe tool utilizes the precise tracking of OptiTrack mocap systems and allows you to measure 3D locations within a capture volume. A probe with an attached rigid body is included with the purchased measurement kit. By looking at the markers on the rigid body, Motive calculates a precise x-y-z location of the probe tip, and it allows you to collect 3D samples in real-time with sub-millimeter accuracy. For the most precise calculation, probe calibration process is required. Once the probe is calibrated, it can be used to sample single points or multiple samples to compute distance or the angle between sampled 3D coordinates.

Measurement kit includes:

• Measurement probe
• Calibration block with 4 slots, with approximately 100 mm spacing between each point.

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  Measurement probe.
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  Calibration block with slots for the probe tip.

Steps

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Calibrated probe in Motive

Step 1: Probe Calibration

1. [Motive] Under the Tools tab, open the Measurements pane.

2. [Motive] In the Measurements pane, access the probe tab.

3. Place and fit the tip of the probe in one of the slots on the provided calibration block.

4. [Motive] While the probe tip is fitted in the slot, click Start Calibration under the probe calibration section.

5. Once Motive starts taking samples, a rigid body will be placed on top of the probe. Slowly move the probe in a circular pattern while keeping the tip fitted in the slot; making a cone shape overall. Gently rotate the probe to collect additional samples. This allows Motive to precisely compute the pivot and calculate the tip location.

Caution The probe tip MUST remain fitted securely in the slot during the calibration process. Also, do not to press in with the probe since the deformation from compressing could affect the result.

6. [Motive] If the probe calibration was unsuccessful, press Reset and repeat the calibration again.

7. [Motive] Once the probe is calibrated successfully, a probe asset will be displayed over the rigid body in Motive, and live x/y.z position data will be displayed under the Real-time Measurement section.

Step 2: Sample Collection

1. First, place the probe tip on the point that you wish to collect.

2. [Motive] Click Take Sample on the Measurement pane.

3. [Motive] A virtual reconstruction will be created at the point, and the corresponding information will be displayed over the measurement pane. The sampled points will also be saved in the exported onto the project directory.

4. Colleccting additional samples will provide distance and angles between collected samples.

Sampling 3D points using the measurement probe.

Set Origin and Set Orientation

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You can also use the probe samples to reorient the coordinate axis of the capture volume. The set origin button will position the coordinate space origin at the tip of the probe. And the set orientation option will reorient the capture space by referencing to three sample points.

Export Samples

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As the samples are collected, their coordinate data gets written into the CSV files in the project directory. 3D positions for all of the collected measurements and their respective RMSE error values will be saved in this file.

Real-time Streaming

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Location of the probe tip can also be streamed into another application in real-time. You can do this by data-streaming the probe rigid body position via NatNet. Once calibrated, the pivot point of the rigid body gets positioned precisely at the tip of the probe. The location of a pivot point is represented by corresponding rigid body x-y-z position, and it can be referenced to find out where the probe tip is located.