Add overlays, timers and effects

An overlay is an effects layer drawn over the video: a study-with-me timer in the corner, a lower third with your name, a bar chart that builds in during a scene, confetti when the report is published. Overlays are edits like any other: they never touch the recording, Undo removes them, and they export in 16:9, 9:16, 1:1, GIF, screenshots and guides.

#Ask for it in words

Type into the Overlays tab's field or the command bar. DemoTake picks a template and its settings, or designs a custom effect, then checks it renders before adding it.

Custom designs use DemoTake AI (set it up in Settings › AI). Templates also work offline.

#Templates

Templates pick up the take's accent color. Each one has a settings form in the inspector; the gallery thumbnails are rendered live by the same engine as the export.

#The study-with-me timer

The Study timer runs on video time, so it stays exact for hours: at 1:02:15 into a 25/5 video it shows the right session and the right second. Settings:

• Focus, Break, Long break (after the last cycle) and Cycles: "50/10 × 4" is 50, 10, 10 and 4.
• Counts: countdown (time left in the session) or stopwatch (time spent).
• Progress: a ring, a bar, or none. Style: minimal (just the digits), glass or bold.
• Start at begins partway into the schedule; Speed runs it faster than real time for time-lapses.

On a study-with-me Composition, the timer follows the composition's own schedule and replaces the built-in timer.

#Custom HTML and CSS

Choose Custom HTML/CSS in the gallery, then Edit HTML/CSS. The editor shows a live frame and tells you what it removed.

• HTML and CSS only. Scripts, event handlers, iframes, forms, media and links are removed. So is anything loaded from the network: images must be data: URLs, and url() in CSS may only point at a data: image or an SVG reference like url(#glow).
• Allowed: layout and text elements, inline SVG (gradients, filters, masks, clip paths), CSS gradients, filters, mask, clip-path, transforms and @keyframes animations. Fonts: var(--font-sans), var(--font-display) and var(--font-mono).
• Size with container units (cqw, cqh, cqmin) so the layout adapts to 16:9, 9:16 and 1:1. --aspect holds the width divided by the height.

#Time, variables and bindings

Nothing depends on the clock: DemoTake sets the time for every frame, so the same frame always renders the same pixels.

Every @keyframes animation is moved to the right moment on each frame, so animation-delay works as a timeline. To show values, bind text with data-bind:

<div class="badge">
  <span data-bind="timer.display:mm:ss"></span>
  <small data-bind="scene.title:upper"></small>
</div>

Keys: t, p, scene.title, scene.index, take.name, timer.display, timer.remaining, timer.elapsed, timer.phase, timer.session, counter.value, clock and param.<name>. Formats after the colon: mm:ss, hh:mm:ss, auto, HH:mm, 0,0, $0,0.00, 0.0%, upper. data-if="timer.phaseKey=break" shows an element only during breaks, and data-repeat="40" makes 40 copies with seeded random values (--r1 to --r4) for particles.

#Placement and layers

• Full frame, Anchored (a corner or edge; keeps its shape when you switch between 16:9, 9:16 and 1:1) or Free (drag and resize on the stage).
• Layer: above everything (default), below the captions, or below the cursor.
• Keep redactions on top blurs redacted areas over the overlay too.

#With agents

Coding agents add overlays over MCP with the same checks: overlay_templates, overlay_add, overlay_update, overlay_remove and overlay_preview, which returns the exact export frame as an image. See the MCP reference. Overlays are saved in demotake.json, so regenerated demos get them again (see Demo specs and CI).

#3D scenes

3D scenes are overlays too: a spinning logo for the intro, 3D columns rising, snow, or the recording itself floating on a tilted screen while the camera dollies in.

Ask for one (add a spinning 3D logo in the intro, make the recording float on a tilted screen and dolly in, make it snow) or pick one under 3D in the gallery. Select a 3D overlay to edit it:

• Objects: boxes, rounded boxes, spheres, cylinders, tori, planes, 3D text, particles, images and your own 3D models (.glb files with embedded textures, up to 15 MB). Select one and drag the gizmo on the stage to move, rotate or scale it.
• Add Keyframe at Playhead records the object's position, rotation and scale at that moment; a move at another time adds another keyframe.
• Camera: Orbit, Dolly and Push in add a camera move from the playhead. Light picks a studio, sunset or night look.
• Replace the frame shows the take's background behind the scene instead of the video, for floating screens.

3D scenes are data, not code: DemoTake's own engine draws them, frame by frame, so exports are exact and repeatable. Agents use scene3d_create, scene3d_add_object, scene3d_update, scene3d_animate, scene3d_preview and scene3d_remove.