Special Input Devices: Using a Polhemus Patriot tracker

To use the Polhemus Patriot with GripTools, you need the specialized Camera GripTools Patriot version.

Camera GripTools Patriot supports the Polhemus Patriot 6DOF Motion Sensor with the USB unit interface. To use the Patriot, you should have installed and setup the device according to the Patriot manual. The Patriot comes with a nice test application, that will demonstrate the basic use. It is very important to get accustomed to positioning the sensor and the magnetic Source.

When everything is setup, you can start the Patriot unit.
Switch on the unit before starting CINEMA 4D. Wait until the Led on the front side has turned green, indicating that the device is functioning fine.
Start CINEMA 4D. If the Patriot is detected, it will appear in the axes selection box.
All 6 axes can be selected just like the axes of other input devices. The Patriots does not offer buttons.

 

We have tested and used Camera GripTools with the standard TX2 source and the RX2 sensor. This combination has a quite stable action radius of 7.5 to +/-100 cm. The radius and the distortion depends on metal objects in the range(see the Polhemus documentation). It’s nice for desktop motion captioning. Polhemus offers alternative equipment with much wider ranges for use in a bluescreen studio. In a desktop setup, we found it convenient to place the source in front at a distance of 50 to 80 cm and at the same height.

Camera GripTools supports the tracker with a special device dialog to adapt the settings into C4D. You may want to experiment with the 3D setup. If you position the source as in the title image, you’ll have a fast match with your scene.
There’s a lot of information in the Patriot manuals. Please read it carefully.
In our 6 D.O.F. video turorial, we demonstrate the tracker's use.

Click here to watch the video

Navigating with the Patriot tracker

Using the virtual tracker device is an ideal solution to move a camera around through a scene, exploring your 3D models in a very natural way.

At one point, you’ll notice the absolute positioning behavior of the Patriot tracker. After you have used the “Special Device Dialog”, to “Boresight” the Tracker sensor and to set the movement "Scale”, slider you will notice that moving the sensor around will always be relative to the center point of the scene.

In some cases it may occur that you need to move relative to a different position in your CINEMA 4D scene. Let’s consider an example.

You are controlling a camera in CameraGripTools, by using the Handheld mode. You have assigned all axes to your Patriot Tracker. In the scene you have a 3D model of a building and you would like to move the camera around on the upper floor. It may be hard to reach this place by physically trying to move the Patriot sensor.
The solution is to place the camera into a “Null Object”, and move this Null Object to the desired location. Now you will be able to move around with the Tracker sensor a lot more easily on this location within the scene.

The same solution can be used if you would like to move around with the scene camera relative to moving objects. Just put the camera or Null Object inside the moving object (e.g. a car), and it will travel alongside the moving object, with relative movements caused by the Tracker sensor.

The trick is to use the tracker as a desktop motion capturing device multiple times on the same camera or other object, to create complicated motion very fast, very natural and intuitive. Yes, motion capturing can be fun this way.

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