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Sources

Every dimension the house is generated from is below, with its class and its citation. This is the project’s honesty layer, and it is given a room of its own because a smooth 3D render implies a precision the sources do not have.

The dimensions

DimensionValueClassWhat it means
ruangLength3.10 mIf 20% out: 3.10 mInterpolatedLength of one ruang along the ridge axis.No source
lanjarDepth2.50 mIf 20% out: 1.50 mInterpolatedDepth of one lanjar, front to rear.No source
lanjarCount3If 20% out: 2.50 mInterpolatedNumber of lanjar. The sources name the lanjar as a division of the interior but do not fix a count for the ordinary house, so this number is the author’s.No source
postSection0.20 mMoves no measurementInterpolatedSection of a tonggak, the underfloor post.No source
padHeight0.25 mIf 20% out: 0.05 mInterpolatedHeight of the batu sandi a post stands on.No source
padDiameter0.46 mMoves no measurementInterpolatedWidth of the batu sandi.No source
kolongHeight1.90 mIf 20% out: 0.38 mInterpolatedClear underfloor height, from the ground to the floor frame.No source
wallHeight2.10 mIf 20% out: 0.42 mInterpolatedHeight of the wall at its foot, from the deck to the wall plate.No source
wallLean8°If 20% out: 0.06 mInterpolatedOutward lean of the wall. The sources state that the body widens toward the plate; none gives the angle, so this figure is the author’s.No source
floorFrameDepth0.26 mIf 20% out: 0.05 mInterpolatedDepth of a rasuak, the floor-frame beam.No source
deckThickness0.05 mIf 20% out: 0.01 mInterpolatedThickness of a floor board.No source
deckBoardWidth0.26 mMoves no measurementInterpolatedWidth of one floor board.No source
wallThickness0.06 mMoves no measurementInterpolatedThickness of a wall board and of a bilik partition.No source
anjuangRise0.42 mIf 20% out: 0.08 mInterpolatedHow far the anjuang floor steps up above the main floor. That the step exists is canon; how high it is, is not.No source
ridgeRise3.20 mIf 20% out: 0.64 mInterpolatedHeight of the ridge above the wall plate, at mid-span.No source
ridgeSag0.42 mIf 20% out: 0.08 mInterpolatedHow far the ridge line sags at mid-span relative to its ends.No source
ridgeEndRise0.50 mIf 20% out: 0.10 mInterpolatedRise of both ends of the ridge. Symmetric: unlike the tongkonan, neither end is the higher one.No source
ridgeOverhang2.60 mMoves no measurementInterpolatedHow far the roof projects beyond the end of the body. This is where the gonjong lives, so the projection is deep: the roof edge has already left the house before it starts to climb, which is why the long façade still reads as a straight eave.No source
ridgeUpsweep0.20Moves no measurementInterpolatedHow far the ridge curve overshoots its control point before rising to the end; this is what makes the ridge a curve rather than a kink.No source
gonjongRise2.60 mMoves no measurementInterpolatedHeight of a gonjong tip above the end of the ridge. The tips stand well above the ridge end, and the hollow between a pair of them is the most recognisable part of the silhouette.No source
gonjongSplay0.58Moves no measurementInterpolatedWhere a gonjong tip stands across the roof, as a share of its half-width. A pair stands wide — footed at the roof edge and leaning inward toward the tips — so the separation is a property of how wide the roof is rather than a length of its own. The author’s reading of the form; no source gives the figure.No source
gonjongReach0.12Moves no measurementInterpolatedHow far the lift reaches back into the body, as a share of its half-length. Nearly all the curve happens outside the house; it encroaches slightly so the transition is not a crease on the gable line. A large value lifts the edge too early, so the roof has flattened to ridge height before it reaches the end wall and there is no gable left.No source
gonjongSweep2.20Moves no measurementInterpolatedHow late the roof edge turns upward into the gonjong. A value of one lifts it in a straight line from the end of the body; a high value holds the eave level and then raises it sharply near the tip.No source
gonjongSparTaper0.25Moves no measurementInterpolatedSection of the verge member at the tip relative to its foot. This is what makes the point a point rather than a cut-off stub.No source
gonjongSparRadius0.06 mMoves no measurementInterpolatedRadius of the verge member that carries the gonjong out to its point.No source
eaveOversail1.35 mIf 20% out: 0.27 mInterpolatedHow far the eave oversails the outer post line, so the drip falls clear.No source
eaveDrop0.90 mIf 20% out: 0.18 mInterpolatedHow far the eave hangs below the wall plate.No source
plateDepth0.24 mMoves no measurementInterpolatedDepth of the wall plate the rafters bear on.No source
plateWidth0.16 mMoves no measurementInterpolatedWidth of the wall plate.No source
rafterWidth0.07 mMoves no measurementInterpolatedWidth of a rafter in section.No source
rafterDepth0.11 mMoves no measurementInterpolatedDepth of a rafter in section.No source
raftersPerRuang3Moves no measurementInterpolatedNumber of rafters per ruang, per side.No source
raftersAtEnds4Moves no measurementInterpolatedRafters added beyond the per-ruang count, for the two projecting ends.No source
ridgeBeamRadius0.08 mMoves no measurementInterpolatedRadius of the ridge beam.No source
purlinRadius0.04 mMoves no measurementInterpolatedRadius of a bamboo purlin.No source
purlinAboveKnee0.50Moves no measurementInterpolatedPosition of the upper purlin, as a share of the run from ridge to the roof break.No source
purlinBelowKnee0.55Moves no measurementInterpolatedPosition of the lower purlin, as a share of the run from the break to the eave.No source
sheathingOffset0.60Moves no measurementInterpolatedHow far the roof boarding sits above the rafter axis, as a share of rafter depth.No source
ijukBedClearance0.02 mMoves no measurementInterpolatedClearance between the roof boarding and the first ijuk course.No source
ijukCourseDepth0.32 mMoves no measurementInterpolatedExposed depth of one ijuk course.No source
ijukThickness0.10 mMoves no measurementInterpolatedHow far a course stands proud of the one below it.No source
ijukLap0.40Moves no measurementInterpolatedThe share of a course that the course above laps over.No source
singokThickness0.05 mMoves no measurementInterpolatedThickness of the singok, the triangular board closing the gable end.No source
sillWidth0.90Moves no measurementInterpolatedWidth of a rasuak, as a share of the post section.No source
postSeat0.30Moves no measurementInterpolatedDepth of the dish in the batu sandi that the post foot seats into, as a share of stone height.No source
tenonRun0.70Moves no measurementInterpolatedHow far a post head runs up into the floor frame, as a share of frame depth.No source
jointEngagement0.30Moves no measurementInterpolatedDepth of the tested joint engagement, as a share of the smaller member.No source
orientation0°Moves no measurementCanonThe front faces the halaman, with the rangkiang ranged across it. The rule is relational rather than a compass bearing — and this is where the rumah gadang differs from the tongkonan, which faces north.Navis, A. A., Alam Terkembang Jadi Guru: Adat dan Kebudayaan Minangkabau (Grafiti Pers, Jakarta, 1984).
ruangIsOdd1Moves no measurementCanonThe ruang count is always odd: three, five, seven, nine.Navis, A. A., Alam Terkembang Jadi Guru: Adat dan Kebudayaan Minangkabau (Grafiti Pers, Jakarta, 1984).
anjuangKotoPiliang1.00Moves no measurementCanonUnder the Koto Piliang laras the floor at both ends is raised into anjuang; under Bodi Caniago the floor is one level plane. The difference in adat is legible as a difference in floor height.Navis, A. A., Alam Terkembang Jadi Guru: Adat dan Kebudayaan Minangkabau (Grafiti Pers, Jakarta, 1984).
gonjongBase4Moves no measurementCanonThe base form carries four gonjong: one at each corner of the roof, where the eave lifts into a point.Departemen Pendidikan dan Kebudayaan, Arsitektur Tradisional Daerah Sumatera Barat (Proyek Inventarisasi dan Dokumentasi Kebudayaan Daerah, Jakarta).
bilikAreTally1Moves no measurementCanonA bilik is added as each daughter marries; their number is a record of how the matriline has grown.Waterson, R., The Living House: An Anthropology of Architecture in South-East Asia (Oxford University Press, Singapore, 1990).
bilikFillOrder1.00Moves no measurementInterpolatedThe bilik fill sequentially from one end with no gaps. That they are added one at a time is canon; the direction of fill and the absence of gaps are the author’s, and they are why this house is not symmetric in its partitions.No source
wallsLeanOut1.00Moves no measurementCanonThe body walls lean outward, widening toward the wall plate.Schefold, R., Domenig, G. & Nas, P. (eds), Indonesian Houses Vol. 1: Tradition and Transformation in Vernacular Architecture (KITLV Press, Leiden, 2003).
noNails1.00Moves no measurementCanonPegged joints; the frame goes up without nails.Schefold, R., Domenig, G. & Nas, P. (eds), Indonesian Houses Vol. 1: Tradition and Transformation in Vernacular Architecture (KITLV Press, Leiden, 2003).
postsOnGrid1Moves no measurementCanonThe posts stand on the grid of ruang and lanjar, symmetric about the transverse mid-plane.Departemen Pendidikan dan Kebudayaan, Arsitektur Tradisional Daerah Sumatera Barat (Proyek Inventarisasi dan Dokumentasi Kebudayaan Daerah, Jakarta).
rangkiangOpposite1Moves no measurementCanonThe rangkiang stand across the halaman facing the rumah gadang. This house’s orientation constraint is relational rather than compass-bound — and these are what it is relative to, so without them the rule says nothing.Navis, A. A., Alam Terkembang Jadi Guru: Adat dan Kebudayaan Minangkabau (Grafiti Pers, Jakarta, 1984).
halamanDepth10.00 mMoves no measurementInterpolatedWidth of the halaman between the house and the rangkiang.No source
rangkiangPlan2.60 mMoves no measurementInterpolatedPlan side of one rangkiang. Only the footprint is drawn: the rangkiang are not modelled, and that is already stated as an absence.No source
rangkiangFloorY1.90 mMoves no measurementInterpolatedHeight of the rangkiang floor above the ground. Only its massing is drawn; every figure here is the author’s.No source
rangkiangBodyHeight1.60 mMoves no measurementInterpolatedHeight of the rangkiang body.No source
rangkiangRoofRise3.40 mMoves no measurementInterpolatedRise of the rangkiang roof above its body. A rangkiang’s roof carries gonjong like the house; this massing is a straight gable and states none.No source
rangkiangPostWidth0.26 mMoves no measurementInterpolatedSide of a rangkiang post.No source
rangkiangEave1.00 mMoves no measurementInterpolatedOverhang of the rangkiang roof beyond its body, on the massing drawn here.No source
rangkiangSpacing5.00 mMoves no measurementInterpolatedSpacing between rangkiang along the halaman.No source

Bibliography

  • navis-1984 · ethnography

    Navis, A. A., Alam Terkembang Jadi Guru: Adat dan Kebudayaan Minangkabau (Grafiti Pers, Jakarta, 1984).

  • vellinga-2004 · ethnography

    Vellinga, M., Constituting Unity and Difference: Vernacular Architecture in a Minangkabau Village (KITLV Press, Leiden, 2004).

  • schefold-2003 · reference

    Schefold, R., Domenig, G. & Nas, P. (eds), Indonesian Houses Vol. 1: Tradition and Transformation in Vernacular Architecture (KITLV Press, Leiden, 2003).

  • waterson-1990 · ethnography

    Waterson, R., The Living House: An Anthropology of Architecture in South-East Asia (Oxford University Press, Singapore, 1990).

  • depdikbud-sumbar · reference

    Departemen Pendidikan dan Kebudayaan, Arsitektur Tradisional Daerah Sumatera Barat (Proyek Inventarisasi dan Dokumentasi Kebudayaan Daerah, Jakarta).

Which of these matters most

Nearly every dimension on this page is the author’s own. What the provenance bar does not say is whether that matters. Each row below is computed by rebuilding the house: one dimension is pushed 20%, and the house is measured to see how far it follows. Nothing is estimated — the figures are the difference between two runs of the generator.

  1. 1ruangLength3.10 mbody length
  2. 2lanjarCount2.50 mbody depth
  3. 3lanjarDepth1.50 mbody depth
  4. 4ridgeRise0.64 mridge height
  5. 5wallHeight0.42 meave height
  6. 6kolongHeight0.38 mridge height
  7. 7eaveOversail0.27 mroof reach
  8. 8eaveDrop0.18 meave height

If only one dimension could be surveyed, this is the one. This is sensitivity, not uncertainty: it shows what moves, not how likely the value is to be wrong. The 20% is itself the author’s choice.

Invariants

There is no measured drawing yet, so correctness rests on structural truth. These checks fail the build.

  • pass
    Bilateral symmetry about the transverse mid-plane

    22967 points (257 of 263 parts); largest mirror deviation 0.00 mm.

  • pass
    Every tenon contained in its mortise

    70 pasak, takik and tumpu joints; every one engaged.

  • pass
    No joint spans more than one stage

    Every joint engages two parts from the same stage or from consecutive ones.

  • pass
    Stage ordering, and nothing below ground

    263 parts, every one bearing on something already standing or on the ground.

  • pass
    Mesh integrity: indices, triangles, normals

    32272 triangles; indices in range, none degenerate, every normal unit length.

  • pass
    The ruang count is odd

    5 ruang; 6 ruang boundaries.

  • pass
    The ridge sags in the interior; both ends rise to the same height

    lowest point at s=0.50 (7.34 m); the two ends at 8.26 m and 8.26 m.

  • pass
    Koto Piliang: the floor at both ends rises into anjuang

    main floor 2.46 m, anjuang floor 2.88 m; a step of 0.42 m over 24 boards.

  • pass
    The gonjong are part of the roof, not masts standing on it

    4 gonjong; highest tip 10.86 m against a ridge end of 8.26 m; the roof reaches every tip within 0.07 m.

  • pass
    The roof edge holds its line, then climbs past the ridge into the gonjong

    level at 3.66 m as far as z=6.82 m, then rising 7.20 m over 3.53 m — a slope of 2.0 : 1 — to 10.86 m, past the ridge end at 8.26 m, narrowing to 3.13 m.

  • pass
    Nothing in the roof frame reaches outside the roof

    78 rafters and gable panels cut to the roof section they sit at; the furthest reaches 35 mm outboard and 54 mm low.

  • pass
    The bilik fill the rear lanjar in sequence, with no gaps

    3 bilik out of 3 interior ruang; consecutive, one ruang wide each.

  • pass
    The walls lean outward; the body widens as it rises

    wall foot 3.75 m from the axis, head 4.05 m; the outermost board reaches 4.07 m at 8°.

  • pass
    Ijuk courses lap with no bare strip; the ridge is covered

    35 courses; smallest lap 2.3% of the slope run.

  • pass
    The eave oversails the outer post line

    eave 5.40 m from the axis; outer post face 3.75 m; oversail 1.65 m.

  • pass
    The eave clears the wall plate

    roof at x=4.05 m sits at 4.68 m; top of the wall plate 4.68 m; eave 5.40 m.

  • pass
    Post count follows the ruang and lanjar counts

    5 ruang × 3 lanjar → 6 × 4 = 24 posts, 24 pad stones.

  • pass
    Every part declares the dimensions it came from

    263 parts, every one tagged. By least-sourced input: 0 measured, 0 canon, 263 interpolated.

  • skipped
    Checked against a measured drawing of a real house

    Skipped. No measured drawing has been wired in, so there is nothing to compare against. This check will not be made to pass by weakening it.

What a check is preventing

Ten green rows are not a reason to believe anything. So one check is run against a house built to break it, and what is printed below is that check’s own verdict rather than a description of it.

This check enforces the one claim in this pack that a reader standing in the room could disprove with a spirit level: under the Koto Piliang laras, the floor at both ends stands above the middle. Flatten the step and the house stops being able to say which adat raised it. The threshold is searched rather than picked — and the step stops being a step before it reaches zero, at the point where it is thinner than the board that forms it.

The house as built

pass2.46 m / 2.88 mmain floor · anjuang floor

main floor 2.46 m, anjuang floor 2.88 m; a step of 0.42 m over 24 boards.

Rear prow raised to 0.04 m

fail2.46 m / 2.50 mmain floor · anjuang floor

No anjuang was built. The step of 0.042 m is thinner than the 0.050 m floor board that would form it, so there is nothing to stand on.

The second house is never rendered. It is built during the build, failed, and thrown away.

This bar moves as real surveys are wired in. That movement is the project's progress metric.