10.1 An object, a moment, and an animation🔗ℹ

A Visual describes one drawable object. A Scene describes an animation, including its time intervals. Sampling the Scene produces a scene state: the objects and values at one moment. A Pict is a Racket picture value made by drawing that state. A movie file contains encoded frames; it is not any of those values.

Quick Start: a moving circle creates each value in that order. Changing a drawing’s appearance does not by itself add duration. Adding a wait adds duration without changing its appearance.

10.2 A variable, an ID, and a path🔗ℹ

A Racket variable refers to a value in your program. An ID is the name stored in a Visual. A Visual path follows IDs through nested groups. For example, ’(pair dot) names a child, not a route through points. Build a small scene shows all three with one small diagram.

A slide continuity key has a different job: it says which content should correspond across two slides. The key is not automatically a target for native Scene animation. See Look closely at a matching title.

10.3 A group and a layout🔗ℹ

A native group stores children in a shared local coordinate system. A slide layout chooses regions for roles such as a title, body, or figure. A slot assigns content to one of those roles. A semantic group names parts inside slide content so a matched transition can retain their correspondence. These solve different problems; similar names do not make them interchangeable. Start with Move several objects together or Keep parts connected across slides, according to the task.

10.4 Duration, start time, and local time🔗ℹ

Duration is the length of an interval. A start time is a position relative to a stated clock. An embedded animation has its own local time; it need not be the same as the time on the slide or the assembled storyboard. Revealing the figure and advancing its clock are separate actions. See Delay the second start and Start its own clock.

An easing function changes progress within an interval. It does not change when that interval starts or how long it lasts. A build changes content within one slide. A transition connects two shots. See Put slides together.

10.5 2D geometry, a construction, and 3D content🔗ℹ

Native 2D Visuals include paths, axes, and graphs. A geometry construction program describes named geometric objects and construction steps. It can be embedded as slide content, but it is not a synonym for every object with a geometric shape.

A spatial Visual lives in three dimensions. A view3d places spatial objects and their 3D camera inside the ordinary 2D Scene. Its 2D placement is separate from the positions of the objects inside it. The 3D reference map is at 3D reference map.

10.6 Preparation, rendering, and encoding🔗ℹ

Preparation does work that frames can reuse, such as typesetting a formula or placing geometry labels. Rendering draws a frame. Encoding turns rendered frames into a video format. A larger worker pool helps only the work that uses that pool; it does not make each stage parallel. See Save frames and make a video and Render a larger project.

Changing a format changes the layout’s shape, such as widescreen versus portrait. Changing resolution changes how many pixels draw that shape. A small preview can therefore use the same layout as a large final image.