< Previous | Contents | Manuals Home | Boris FX | Next >
Configuring Constraints for Tripod-Mode Shots
When the camera is configured in tripod mode, a simpler coordinate-system setup can be used. In tripod mode, no overall sizing is required, and no origin is required or allowed. The calculated scene must only be aligned, though even that is not always necessary.
The simplest tripod alignment scheme relies on finding two trackers on the horizon, or at least that you’d like to make the horizon. Of the two, you assign one to be the X axis, say, by setting it up as a Lock to the coordinates X=100, Y=0, Z=0, for the
normal World Size of 100. If the world size was 250, the lock point would be 250, 0, 0 : a Far tracker should always be locked to coordinates where X squared plus Y squared plus Z squared equals the world size squared. It is not necessary for the constraint to work correctly, but for it to be displayed correctly.
With one axis nailed down, the other tracker only needs to be labeled “On XY plane,” say (or XZ in Y-Up coordinates).
If you have an estimate for the field of view, you can preposition the camera, then right-click the Nudge Tool on the Coordinate System panel to create seed/lock coordinates that lineup exactly with the 2D tracker position on the current frame. Two will constrain the initial camera orientation.
Tip : if you have a tripod shot that pans a large angle, 120 degrees or more, small systematic errors in the camera, lens, and tracking can accumulate to cause a banana- shaped path. To avoid this, set up a succession of trackers along the horizon or another straight line, and peg them in place, or use a roll-axis lock .
©2024 Boris FX, Inc. — UNOFFICIAL — Converted from original PDF.