[ Lecture Outline<\/a> ] [ Lab Exercise<\/a> ] [ Homework Project<\/a> ]<\/p>\n The 3D Camera Tracker feature is used to combine real-world footage with computer-generated 3D text or visuals, even 2D stuff too.<\/p>\n Useful for simple tracking tasks. Fast to work with. Can be used to track the position of a single feature in some footage, or up to four features at once in order to also determine perspective, scale, rotation.<\/p>\n The basic steps are: <\/strong> All tracking data is 2D.<\/strong> When applying<\/strong> tracked perspective<\/strong> to a target layer,<\/strong> the Corner Pin effect<\/strong> is used to simulate<\/strong> 3D depth. This effect is actually a 2D effect.<\/em><\/p>\n Handy for more complex tracking. Generally used for tracking arbitrary surfaces<\/strong> of stationary objects<\/strong> in a moving shot,<\/strong>\u00a0and then applying that track data to 3D properties of layers.<\/p>\n For example, in a handheld shot of a city, buildings, parked cars, and sleeping people<\/strong> would “track well” because they’re stationary, but moving cars and people<\/strong> would not.<\/strong> We could track some surface of a building and then put a 3D layer at that spot in 3D space.<\/p>\n The basic steps are:<\/strong> With the 3D Camera Tracker, moving objects like people, cars, etc. can confuse the tracking analysis.<\/strong> It’s important to try and remove moving objects from the shot using techniques like masking, animated masking, mask tracking, rotobrush, etc.<\/p>\n You can use the “Create Shadow Catcher” to create a special horizontal layer that only displays shadows.<\/p>\n Sometimes you need to use the 3D Camera Tracker’s tracking data to control properties of a 2D layer.<\/strong> The 3D points in the tracking data need to be converted to 2D space on each frame. Expressions can help here.<\/strong><\/p>\n First, enable expressions<\/strong> on the 2D property<\/strong> that will be the “target” of the 3D data. For example, we might choose the\u00a0Bulge Center<\/strong>\u00a0property of a the Bulge<\/strong> effect.<\/p>\n Then add the following expression:<\/p>\n The expression above can also be written a lot more concisely, like this:<\/p>\n Or simply:<\/p>\n But,<\/strong> when starting out it can be helpful to be overly verbose with scripting.<\/p>\n","protected":false},"excerpt":{"rendered":" 3D Camera Tracker [ Lecture Outline ] [ Lab Exercise ] [ Homework Project ] The 3D Camera Tracker feature is used to combine real-world footage with computer-generated 3D text or visuals, even 2D stuff too. Basic Tracking Useful for simple tracking tasks. Fast to work with. Can be used to track the position of … <\/p>\nBasic Tracking<\/h2>\n
\n (1)<\/strong> Track feature (2)<\/strong> Apply the results to a Target<\/strong>\u00a0(a layer or effect property.)<\/p>\n3D Camera Tracking<\/h2>\n
\n (1)<\/strong> Analyze Clip \/ “Solve The Camera” \u00a0(2)<\/strong> Find a “target plane” amongst the track points \u00a0(3)<\/strong> Create a 3D Null and Camera (4)<\/strong> Copy\/Paste properties (like position<\/strong>) from the 3D Null Layer onto some other 3D property (e.g., another layer’s 3D position property.)<\/p>\nMasking Out Moving Objects<\/h2>\n
Shadow Catcher<\/h2>\n
Connecting 2D Layers To 3D Tracking Data<\/h2>\n
\/\/ Use a variable to make an 'abbreviation' for the 3D Null Layer:\r\nmy3dLayer = thisComp.layer( \"nameOf3DNull\" );\r\n\/\/ Do the same for that layer's anchor point:\r\nmy3dAnchorPoint = my3dLayer.anchorPoint\r\n\/\/ Convert the 3D point to 2D space\r\nmy2dPoint = my3dLayer.toComp( my3dAnchorPoint );\r\n\/\/ Last line is the value that the property will use:\r\nmy2dPoint;<\/pre>\n
\/\/ Use a variable to make an 'abbreviation' for the 3D Null Layer:\r\nmy3dLayer = thisComp.layer( \"nameOf3DNull\" );\r\n\/\/ Convert the 3D point to 2D space. Last line will be value used for property.\r\nmy3dLayer.toComp( my3dLayer.anchorPoint );<\/pre>\n
my3dLayer = thisComp.layer( \"nameOf3DNull\" ); \r\nmy3dLayer.toComp( my3dLayer.anchorPoint )<\/pre>\n