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AI App Builder Architecture: Scene Graphs, State Forking, and Real-Time Runtime Design

Dreams.fm TeamDreams.fm Team
February 10, 20263 min read54
AI App Builder Architecture: Scene Graphs, State Forking, and Real-Time Runtime Design

If you are building an AI app builder, your architecture decision happens early:

  • Do you center everything around prompt-response calls?
  • Or do you model a persistent world where changes can be applied, replayed, and projected?
  • The first option looks simpler. The second option scales.

    This post explains why we use a scene-based runtime model at Dreams.fm.

    The architecture trap in many AI builders

    Many teams ship quickly with this pattern:

  • user request,
  • model output,
  • patch UI,
  • repeat.
  • It works for small demos.

    Then real requirements arrive:

  • "Can we undo this branch and keep the alternative branch?"
  • "Can we apply the same change to mobile and desktop surfaces?"
  • "Can we replay exactly what happened in this session?"
  • "Can text, speech, and direct edits use one source of truth?"
  • Prompt-response architecture collapses because state transitions are implicit and fragile.

    Scene-first runtime model

    We treat each project as scenes plus timeline state.

    A scene includes:

  • structural nodes (layout, components, entities),
  • semantic intent (purpose, interaction state),
  • output bindings (web, stream, and presentation surfaces).
  • Every edit becomes a transform against scene state.

    That gives us:

  • deterministic updates,
  • explicit causality,
  • branchable history,
  • reversible operations when possible.
  • Why scene graphs work for AI app builders

    Scene graphs solve three practical problems.

    1. They preserve hierarchy

    Generated output is not a flat blob. It has dependencies, constraints, and parent-child relationships.

    Scene graphs make this explicit, which makes targeted updates safer.

    2. They support multi-surface projection

    The same scene can render to different outputs:

  • product UI,
  • live preview,
  • media render surface,
  • presentation layer.
  • Without duplicating business state.

    3. They make branching real

    Teams can fork scene state, test alternatives, and merge decisions based on outcomes. That is essential for iterative product work.

    State forking and timeline memory

    Forking is not a convenience feature. It is how teams reduce risk.

    With timeline memory:

  • every transform has provenance,
  • every branch keeps context,
  • every merge decision is inspectable.
  • This matters most when AI-generated and human-authored changes coexist.

    Input parity in a scene runtime

    Multimodal input only works when every input type resolves to typed transforms.

    Useful commands can come from text, speech, structured action calls, or direct editor actions. All of them should end in the same runtime semantics.

    Examples:

  • "Move this interaction to scene two"
  • "Tighten spacing scale by one step"
  • "Generate a hero variant with stronger conversion copy"
  • When inputs map to typed transforms, teams keep control.

    Runtime design principles we follow

    For a production AI app builder:

  • State before rendering: UI is projection, not source of truth.
  • Transforms before side effects: edits are explicit operations.
  • Timeline before shortcuts: history must survive sessions.
  • Branching before destructive updates: experimentation should be safe.
  • Shared runtime before tool silos: code, design, and media need one model.
  • Where this meets SEO and product strategy

    People search for "ai app builder" because they want end-to-end execution, not isolated generation.

    Architecture content attracts qualified users evaluating platform depth and migration risk. It also creates durable organic value because these decisions persist beyond short release cycles.

    Closing

    If you are serious about building an AI app builder, architecture is your product.

    Scene graphs, timeline memory, and transform-based execution are the systems that keep your platform coherent as use cases expand.

    This is the foundation behind Dreams.fm and fmEngine as private beta scales.

    #ai app builder#scene graph#real-time ai#state management#ai studio#multimodal ai

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