Assembly Mode — Sub-system Design Doc#

Retroactive design doc — documents the original product mode and its evolution. Last updated: March 2026

Overview#

What Is This Sub-system?#

Assembly Mode is the original product vision for Routr — a full furniture design-to-manufacture pipeline. Users design individual boards, connect them into assembled furniture using joints, preview the result in 3D, nest boards onto stock sheets for efficient material use, and simulate the CNC toolpaths before exporting G-code.

It represents the multi-board, multi-step paradigm: Design → Assembly → 3D Preview → Nesting → Simulation.

The Story#

Assembly Mode was the first thing built. The idea was ambitious: model an entire piece of furniture, define how boards connect with joints, let the app figure out the 3D positioning, then lay everything out on stock sheets and generate G-code for the whole project.

The problem was combinatorial complexity. Supporting every combination of board shapes × joint types × edge connections × assembly configurations was an enormous surface area. After months of development, Assembly Mode could essentially make boxes — which is useful, but far from the vision.

The strategic pivot came when Workshop Mode was conceived: instead of modeling entire assemblies, focus on single boards and think in terms of woodworking tools (table saw, router, drill press). This dramatically reduced complexity while delivering immediate value to CNC owners. Workshop Mode became the launch product, and Assembly Mode was feature-flagged off — still functional, still valuable, but not ready for prime time.

Assembly Mode remains the long-term vision. Workshop Mode gets users in the door; Assembly Mode is where the product grows.

Current Status#

Architecture#

System Boundary#

Assembly Mode owns the multi-board workflow: board linking, joint generation, constraint solving, 3D positioning, and the assembly-specific UI (AssemblyCanvas, 3D Preview tab). It shares the board design surface (Board Setup tab) with Workshop Mode, and delegates to the G-code Pipeline and Simulator sub-systems for output.

Architecture Diagram#

graph TD
    subgraph AM["Assembly Mode"]
        BS["Board Setup<br/>(shared w/ Workshop)"] --> JS["Joint System<br/>(geometry mods, toolpaths)"]
        AC["Assembly Canvas<br/>(edge-click linking UI)"] --> CS["Constraint Solver<br/>(BFS, conflict detection)"]
        AC --> P3D["3D Preview<br/>(Three.js assembly view)"]
        CS --> JS
        JS --> NEST["Nesting<br/>(stock sheet layout)"]
    end

    NEST --> GCP["G-code Pipeline (sub-system)"]
    GCP --> SIM["Simulator (sub-system)"]

Key Interfaces#

Related Epics#

Cross-Cutting Concerns#

Decisions Log#

Risks & Constraints#

Known Issues / Tech Debt#

Assembly Mode is the long-term product vision. Workshop Mode is the launch vehicle. This sub-system doc captures both the architecture and the strategic narrative of how they relate.