Your Guide: Nick Jushchyshyn
Compositing Group Director, PixelCorps
STEP 1: Shoot the live action
Setup your shoot with a decent amount of distinct contrasts and camera movement. This shot, for example, has plenty of natural tracking points in the texture of the wood, ground and shadow corners, as well as significant motion as the handheld camera pushes towards the character. If your shot only calls for subtle camera motion, you can always add a little motion by offsetting the camera a bit before or after the portion of the shot that will be used in the final edit.
STEP 2: Import and Configure the shot
When Boujou Bullet is launched, a project wizard is available at the bottom of the window that can guide you through the process of setting up the matchmove. The first two panels are easy enough: Name and save your new (still empty) project and then select your video file. Next, Boujou will ask for the frame range, but you can address this and a number of other settings all at once by clicking the More button to access the Import Sequence dialog box.
You can also use this dialog to select a Nodal or Free Camera matchmove solution (select Free Camera for a dramatic move like this) and designate the field order, if any, for the frames. To finish your shot configuration, move on to the next step in the wizard to ensure the camera properties were correctly detected by Boujou. Pay particular attention to the aspect ratio and lens squeeze values, as these can be different from the defaults if you used an SD camera in widescreen mode or an anamorphic lens.
STEP 3: Mask random movement
It’s important to mask over any movement in the shot that’s not related to the motion of the camera, such as a moving car, trees swaying in the wind or a character in the scene. Boujou lets you import a mask from another video source or create and animate one on the fly directly in Bullet.
When creating a mask in Boujou, you can easily animate individual points or lines of the mask, or use the arrow-shaped widget control inside the mask to scale (the back of the arrow), move (the square at the center of the arrow) or rotate (the tip of the arrow) the entire mask.
STEP 4: Track it and define coordinates
At this point, Boujou really has all the information it needs to track the shot and give you a 3D matchmove. Once Boujou has finished tracking, all that remains is to orient and scale the coordinate system so that it’s properly aligned with the real-world scene.
Boujou’s Scene Geometry dialog box lets you select individual or multiple 3D locators to use various landmarks when defining your coordinate system. The origin can be defined by a single locator, while a cluster of points can be used to define a ground plane and pairs can be used to define axis direction and measurements, among other things.
STEP 5: Export the matchmove
To finish, Boujou provides an export tool to create a scene file in various formats that can be directly used by most popular 3D applications and compositing tools. The exported scene will contain a moving camera, as well as null references based on the positions of the 3D locators it used during tracking. You can use these references in the application of your choice to add CGI and other effects to the live action plate as the camera moves.
Nick Says Keep in Mind...
Your matchmove work in Boujou will be significantly more accurate and even easier if you plan your shoot to include lots of distinct points of contrast spread throughout the 3D space in front of your camera. Boujou thrives on these tracking points. Significant camera motion that creates visible parallax (points closer to the camera moving faster than those further away) in the shot is also encouraged. It’s actually easier for Boujou to solve a 3D matchmove for a large camera movement than a small shift in position.
Comments (1) for "Create a 3D Camera Matchmove with Boujou Bullet"
.gif){kind=small}
Post your comments below
