Commotion 1.5.5 has the ability to export motion tracker data as 3D Pan and Tilt information. This .obm file format can be read by ElectricImage Animation System and ElectricImage Broadcast (EI Broadcast requires the Motion Capture Plug-in which can be purchased from ElectricImage for $199). With this new functionality, Commotion can help you easily integrate live action footage and CG shots.
In Commotion:
1. Take a shot in which the camera pans and tilts into Commotion.
2. Track an area in your shot.
3. Choose “Save all Trackers” from the Tracker palette’s pop-up menu.
4. Select “3D Pan and Tilt” from the Format pop-up menu, and click OK.
5. In the “Export to 3D” dialog, keep Export Data As “Stabilize”. Click OK.
6. Enter a Field of View (this should match your EI camera FOV), and click OK.
7. Commotion will save out an .obm file as a text file.
A note about Field of View (FOV):
When shooting, make sure to take notes on how far your camera is from the center of interest, as well as your field of view (FOV) and focal length. If not possible, you could go into Electric Image under "Camera Setup" and set up the lens you want to match. The "Focal Mode" (aperture) should be set to horizontal. "Focal Length" is for your lens (i.e. 50 mm). This will give you a FOV number to use.
In ElectricImage:
1. In ElectricImage import the shot which you tracked into your Camera View background. This can be done by double clicking the camera, selecting the “Roto/Comp” tab, and adding he shot to the background list.
2. Option click on the color bars icon at the bottom of the camera view, and choose the background shot. It is now showed in the Camera window.
3. Set the Field of View for your camera in the FOV tab in the Camera window.
4. Choose File->Add->Motion Data (if this is gray you need to buy the plug-in from EI). Select your saved .obm file - which is the same file you saved out of Commotion. Click OK for the following three dialogs. An effector hierarchy is added to your project window. The child effector contains the pan and tilt data, and the parent is used for world placement.
5. Double click the camera and effector parent. Copy the Camera’s x,y,z coordinates into the parent effector’s x,y,z coordinates.
6. Add a rough 3D representation of your center of interest to the shot. This will allow you to set up your initial camera angle.
7. Adjust the camera so the center of interest matches the 3D representation.
8. Link the camera to the child effector.
9. Add your CG element to the shot and render. The object will be properly tracked.
