Super Adobe Generator

▶ Live app: https://soboof.github.io/superadobe-generator/ — free, in your browser, no install.

A browser-based 3D design tool for superadobe / earthbag domed structures. Lay out a complex of domes, set their openings, then drop into a layer-by-layer construction model that estimates materials, time, and an eco score.

No build step — open index.html on a static server (Three.js r134 is loaded from a CDN).

npx serve -p 3737 -s .     # then open http://localhost:3737

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Three-stage workflow

The header switches between three stages:

Stage	Purpose	Controls shown
1 · Layout	Massing: add/position domes, set shape, openings, corridors. The 3D view shows the unified smooth shell (domes merged into one monolith, doorways and intersections subtracted).	Structures, Type, Dimensions, Placement, Openings
2 · Layering	Construction: the same complex shown course by course (capsule bags along each layer curve), plus material/time/eco results.	Bag/Course, Fill, Crew, layer toggles, course stepper
3 · Simulation	Performance: the dome colour-mapped by stress / utilisation / bearing, with structural / thermal / seismic / wind read-outs.	Material model, load case, field selector, verdict + checks

The geometry is identical in all stages — only the render mode (SceneBuilder.setRenderLevel) and which control panels (data-level) are visible change. Panels can target several stages (e.g. data-level="2 3"); levels.js toggles a level-N body class.

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The geometry engine (js/superadobe.js)

Based on:

• López, González, Llauradó — "Equations that describe the geometry of Superadobe domed structures" (3er CIIE, UPM).
• López Gómez, M.A. — "A study of the geometry and structural performance of Superadobe domes" (Doctoral thesis, UPM, 2021).

Dome profile (revolve / "spin"). A dome is a circular arc revolved about the vertical axis, with the arc's centre offset horizontally by a (gives the pointed, paraboloid-like profile — not a hemisphere):

x(h) = √((Rb + a)² − (h − h1)²) − a          (inner ring radius at height h)
H    = h1 + √((Rb + a)² − (Rt + a)²)          (total height)

Rb = base radius · a = arch offset (pointiness) · Rt = skylight radius · h1 = cylindrical base height.

Courses live only on the course-height grid. The profile is sampled every hs (one ring per bag height, §3.6.6) and ends at the last ring that actually rests on the one below — there is no extra ring at the theoretical arc top, and a course whose inward step exceeds the flat bag width L = sw − hs (paper eq. 8′ with F ≤ 0 — it would float) is refused, truncating the dome. Rt is therefore a lower bound ("t_min" in the thesis); the achieved skylight radius — the top ring's inner radius — is reported live under the Skylight slider.

Geometric coherency F (paper eq. 8′). For every pair of consecutive rings, F = (L − step)/L is the fraction of the flat bag width still bearing on the ring below. The worst pair is shown as a live green/amber/red bar (Layout and Layering stages, since diameter, shape, skylight, bag width and course height all move it). SuperAdobe.coherency.

A dome can also be closed at the top ("Closed top" option): the skylight is sealed to a tiny apex and the Stage-1 shell gets a smooth rounded cap (buildShellGeometry, s.closedTop).

A "Conventional — rr = 2·rb + sw" button sets the pointiness to the thesis's standard shape (the vertical compass planted on the outer edge of the base sack, Fig. 3-28); the shape label reads "conventional" whenever the slider is on it.

Plane slicing is the single source of truth. At any height, each dome is a circle; the layer curve is each circle's arc that lies outside every other dome (union boundary) and outside any opening (sliceSpans). Both stages consume it:

• Stage 1 shell lofts the slice-curves over fine height steps into one welded surface (buildShellGeometry).
• Stage 2 courses sweep a stadium (capsule) bag section — flat top/bottom, rounded inner/outer faces — along the same curves at course-height spacing (buildCourseGeometries → sweepSection).

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Construction rules (from thesis §3.6)

• Opening quadrant rule (§3.6.9). Max 4 openings, one per imaginary quadrant; wall arc between openings ≥ 1.25 m — evaluated at the heights where the openings actually are, on the shrinking ring radius x(h), not at the base. Ideal door 1.5 × 1.8 m, window 1.0 × 1.5 m. Violations show as warnings. computeOpenings / validateOpenings.

• Openings snap to the course grid (§3.6.7). Molds sit on top of a finished ring, so every sill and springline lands on a course boundary. The door mold is set once the wall reaches 0.2–0.6 m, so whole threshold courses run continuously under the doorway (the strongest tie in the structure); the door's 1.8 m clear height is measured from the mold base and the head bag rests on a completed course.

• Barbed wire — double line, toward the interior (§3.6.6). Two strands are stitched into the bedding joint on top of every course, laid astride the NEXT ring's centreline (biased inward "to hold in place the next ring"). The top ring gets no wire. The calculator counts 2 × (perimeter + 1.25 m) per joint; the 2D section draws the strands as dots (they cross the section plane). buildWireGeometries.

• Base buttress (§3.6.8–3.6.9). Optional real element (checkbox in Foundation): an extra sack wall hugging the dome's outer face up to 50 cm above the springline, sewn on with double wire, cut at doorways/corridors and neighbour intersections, included in material and time totals. The Ø > 1.5 m advisory points to it. buttressCourses.

• The intersection rule (§3.6.8). Where two domes meet, each course alternates by junction: one dome's bag extends a half-bag past the seam (covers) while the other stops a half-bag short (butts). Roles swap diagonally between the two junctions and flip every layer. The shell uses a plain clean union (no offset). intersectionGaps.

• Staggered joints / 20° spiral (§3.6.6). A full-circle course (the perfect rings above the openings) is a closed seamless loop whose joint start rotates 20° per layer, so the closures spiral up the dome and no sack ends where the one below ended. Rings already broken by an opening or intersection are left as-is. buildCourseGeometries(..., courseIndex).

• Interlock radius. Courses trim against the neighbour's centerline (so bags reach each other and interlock); the shell trims against the neighbour's outer wall (clean watertight merge).

• Ideal apse (§3.6.8). Centre on the outer edge of the main dome's base sack; outer base edge → main apex at 45°; acts as a buttress. "+ Ideal Apse" button. idealApse.

• Sack sizing (Table 3-1). Recommended bag width/height by base diameter, surfaced as a hint. recommendedSack.

• Door corridor (§3.6.7). Optional entrance hall guided by a deep door mold: stadium-bag jambs + a stadium "vault" arch. buildCorridorGeometries.

• No-door default. Only the first dome gets a door; domes added after it default to none.

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Simulation engine (js/simulation.js, Stage 3)

A deterministic, closed-form analytical engine — not a finite-element solver — implementing the ring-by-ring limit-state model from thesis ch. 6 (validated there against Ansys FEA in ch. 7), combined with membrane shell theory:

• Discrete block model (Heyman "safe theorem"): per-ring weights, kern-bounded thrust, bearing area, sliding, bag tension → the limit-state PASS/FAIL checks.
• Membrane shell theory: meridional + hoop stress of the shell of revolution. Reproduces the classic result — hoop compression in the cap, tension below the neutral ring (~52°) — i.e. exactly where the bags + barbed wire carry the tension the earth cannot.
• Wind (pressure-coefficient drag, feeds global roll-over/sliding), Seismic (equivalent static base shear), Thermal (transient earthen wall: U-value, time lag, decrement).

Validated against the thesis FEA envelope: peak tension/compression < 1.4 MPa, shear < 0.7 MPa. Simulation.analyze(structure, others, env) returns per-ring fields + global checks + verdict; the 3D shell is painted per-vertex by the selected field. See docs/SUPERADOBE-STUDY-AND-SIMULATION.md for the full study of the source books, the comparison, and the simulation research.

Files

File	Responsibility
index.html	Layout (3-column: controls · viewport · results), data-level tags per stage
css/style.css	Dark theme, CSS custom properties
js/superadobe.js	Geometry engine — profiles, slicing, shell loft, bag sweep, openings, intersection rule, corridors
js/calculator.js	Material quantities (continuous sack cut per ring + 1.25 m overcut; openings carved from every ring per paper eq. 10′), time from the thesis §3.6.12 rate (~0.1875 m of laid sack per man-hour), eco score; aggregateComplex for the whole site
js/simulation.js	Structural / thermal / seismic / wind analysis (Stage 3) — thesis ch. 6 model + membrane theory
js/main.js	Three.js scene, orbit controls, render-level switch (1/2/3), sim heat-map paint, raycast pick
js/ui.js	Structure list + per-structure controls; drives scene/calculator/layer-plan/simulation
js/levels.js	Stage 1 ↔ 2 ↔ 3 switching
js/layerplan.js	2D cross-section drawing (oval/stadium sections + layer curve)
docs/SUPERADOBE-STUDY-AND-SIMULATION.md	Study of both source books + comparison + simulation spec
.claude/launch.json	npx serve config for the preview

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Notes

• Script order matters: main.js must load before ui.js (it provides SceneBuilder).
• In a backgrounded dev preview the initial requestAnimationFrame render can sit idle and WebGL screenshots can hang — neither happens in a normal visible browser; any interaction kicks the first render.