Match Moving with Maya

Hello Students,
Your next project is an exercise in Match Moving. You will shoot an appropriate video clip, use a program to analyze it for motion tracking data, then use that data to insert a 3D object into your scene seamlessly.

Match Moving Project:
In cinematography, Match Moving is a technique that is widely used to insert both 2d and 3d computer generated images into live action footage. This ensures that the inserted CGI has the correct position, scale and orientation relative to the live action motion. This is also described as motion tracking or camera solving. The technology is essentially an automated method for rotoscoping (adding CGI to live action frame by frame)  and photogrammetry (creating accurate measurements from photographic imagery).

For this project you will need to shoot a short piece of video to use but make sure you shoot video footage that can be easily analyzed and is appropriate for the visual effect you are trying to create. You will then use Autodesk's Match Mover program to track points in your video, Match Mover can then export a Maya file, open that file and you will see an animated camera to use for setting up your 3D objects. Render out the 3D layer and merge it with your original video with Adobe After Effects. Follow the steps below but have a plan of action before you begin for best results.

Step 1: Shoot Your Video
Before you shoot your video you need to have a plan of action, what visual effect are you trying to create? This technique works best when the camera motion is not too frantic, camera should be steady and smooth, and the scene should have good points for the tracking software to use. With this technique you can create things like a ufo or spaceship flying overhead, or add an element to a scene such as adding a coffee cup to a desk or table. Sometimes this method is used to add a text title into a scene which has a cool 3D effect. Whatever you concept is make sure you plan it before shooting your video. Make sure your clip isn't too long, 10 to 30 seconds is plenty, the longer the video clip the more 3D rendering must be completed, which can be time consuming.

Step 2: Prep Video For Tracking

• Open After Effects and import your video
• Create a composition for your video that matches the video resolution (720x1080, etc)
• Trim your video with the in and out markers
• Select Make Movie from the Composition menu
• In the Render Queue change the Output Module setting to PNG Sequence
• Click the file name next to "Output To:" and create a new file called "video_seq" in your project folder, this way your image sequence is in a folder by itself when exported
• Click the Render button and check the results, you should now have a PNG file sequence of your video, this is what the motion tracking software needs to complete the analysis
• Save your AE file to your work folder for use later

Maya Match Mover analyzing an image sequence

Step 3: Create Your Motion Track

• Open your Applications Folder and locate the Autodesk Folder, open it and Launch the Match Mover program
• From the File Menu choose "Load Sequence" and navigate the program to your "video_seq" folder. Double click on the first image in your sequence and it will load into the program timeline
• From the 2D tracking menu choose Automatic Tracking and click Run, the program will now create tracking points and analyze your sequence frame by frame, this can take 2-10 minutes
• Green track lines are good tracks, yellow are fair to poor track points and red are bad track points. If you have too many yellow and red tracks your video isn't good enough, try reshooting and make sure there are distinct points in your scene for the tracking software, remake your sequence and try again
• If your track is good you will see mostly green and some yellow tracks, play the track back to make sure it looks good
• Under the File Menu choose Export, select Maya as the file format and export the file to your work folder  

Virtual tracked camera view in Maya, green lines are tracking points

Step 4: Create 3D Scene with Tracked Camera

• Open your Maya file that you exported from Match Mover. 
• In your view window click on Panels, then Perspective and select rzCamera1... this should change your view to your tracked camera
• Click the play button to see it move, if you have too many tracking points you can turn off their visibility by selecting Show in the view panel and deselecting "locators"
• Add a 3D object to your scene, something simple just to test placement, click the render button to see the results. Create a few more objects or model your spaceship, coffee cup or 3D type that you want to use in your scene
• Do a few test renders to make sure it looks good, when you are ready to render set up your rendering options(window/render editors/render settings) and create your 3D project directory(file/set project) in your work folder. Render your 3D frames, make sure to set the Image plane of rzCamera1 to a display mode of "none" before rendering

Step 5: Merge 3D and Live Action Together

• Open up your AE file that you saved earlier
• Import your newly rendered 3D image sequence into AE
• Add your 3D sequence on top of your video 
• Click the RAM Preview button to see your animation
• Consider any enhancements you can make such as depth of field effect, color matching, masking, etc. 
• Render out an MP4 video of your project and turn it into Mad Max when complete!