Some good info here but perhaps a bit more will be helpful - When talking about Anchor Point and Position values, we are talking about distances or measuring a distance; from Point A to Point B or Start Point to End Point. When measuring distances, much like measuring with a ruler, we require two points of references. IMPORTANT NOTES - Point of Origin - this defines point [0,0] for a Composition and a Layer. When you look at a layer in the composition, you are essentially looking at TWO Coordinate Systems; one for the Composition and the other for the Layer. The Point of Origin is usually used as the Starting Point for calculating distances such as the Anchor Point and Position. Composition Point of Origin - this is at the Top Left Corner of the Composition Window and has a Cartesian Product value of [0,0]. Layer Point of Origin - this differs between the Types of Layers in After Effects BUT they all have a default value of [0,0] - this distinctive [0,0] is a critical characteristic of a Point of Origin. For a Shape Layer, its Point of Origin is at the center of its Rectangular Boundary. For a Solid/PNG/Video/Nested Composition, their Point of Origin is the Top Left corner of their respective Rectangular Boundary. CALCULATING/UNDERSTANDING ANCHOR POINT AND POSITION VALUES Anchor Point Value - this value is derived from its position relative to the layer's Point of Origin. Position Value - this value is derived from its Anchor Point's position relative to the Composition's Point of Origin. In a Parent-Child Hierarchy, the Child Layer's position value is its Anchor Point relative to the Parent Layer's Point of Origin since it now lives in the Parent Layer's space and not Composition Space. HTH
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