Infinite tapes

A tape is a structured plane inside Matemium’s 3D world. In tape-scroll mode it behaves like an infinite document: content flows vertically, reveals as the camera reaches it, and remains addressable after appearing.

Create the main tape

builder = CanvasBuilder(title="Supply and Demand")
tape = builder.add_tape("main")

tape.add_heading("A market moves toward equilibrium")
tape.add_body("Demand falls as price rises.")
tape.add_body("Supply rises as price rises.")

Content added through the tape is laid out relative to other content on that tape.

Why elements persist

Revealed elements are stored in a registry. Later timeline operations can focus, transform, or revisit them without rebuilding the object.

Assign an explicit identifier when you need to reference an element later:

tape.add_math(r"Q_d = Q_s", id="equilibrium")
builder.add_camera_focus("equilibrium", zoom=1.8, hold_time=1.0)

Multiple tapes

Use multiple tapes when an explanation has parallel spatial contexts:

left = builder.add_tape("claim")
right = builder.add_tape("objection")

left.add_heading("Claim")
left.add_body("Knowledge requires certainty.")

right.add_heading("Objection")
right.add_body("Fallible beliefs can still be justified.")

When timeline content switches between tapes, Matemium manages the active tape-scroll context. Do not manually imitate tape switching by dragging or stacking text objects.

Tape view and world view

A tape has two useful interpretations:

• Tape-scroll view — document layout, local scrolling, lazy reveal, and focus.
• World view — the tape is a plane that can be positioned and observed in 3D.

Free 3D objects do not inherit tape layout behavior. Only tape content flows through the tape’s internal layout system.

After a 3D moment

Content that follows certain 3D elements may need to declare that relationship:

builder.add_3d(r"z = \sin(x)\cos(y)", pitch=50)
tape.add_body(
    "Return to the explanation after inspecting the surface.",
    after_3d=True,
)

Good uses for multiple tapes

• Compare two models
• Claim and objection
• Source code and execution state
• Cause and consequence
• Two languages or sentence transformations
• Diagram and notes

Use a new tape for a meaningful spatial context, not merely because the source file has another paragraph.