Sources — Uma — Rumah Adat Nusantara

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

Dimension	Value	Class	Citation
Width of the uma, across.width	8.40 mMoves no measurement	Interpolated	No source
Length of floor for each household in the closed room. The same for every one of them, and none is larger than another.shareLength	2.90 mIf 20% out: 2.90 m	Interpolated	No source
Depth of the front veranda, where anybody may come and where decisions are taken.frontDepth	6.20 mIf 20% out: 1.24 m	Interpolated	No source
Depth of the back veranda, where the women work and where outsiders do not go.backDepth	3.60 mIf 20% out: 0.72 m	Interpolated	No source
Height of the floor above the ground, on ironwood posts standing on stones.floorHeight	1.05 mIf 20% out: 0.21 m	Interpolated	No source
Section of an ironwood post.postSection	0.24 mMoves no measurement	Interpolated	No source
Height of the river stone under a post. Nothing is buried: the frame stands on them, on an island that shakes often.padHeight	0.28 mIf 20% out: 0.06 m	Interpolated	No source
Depth of the hollow in the stone the foot of a post sits in. Without it the post only touches its stone on one plane, and a joint whose members do not enter each other holds nothing.padSocket	0.05 mMoves no measurement	Interpolated	No source
How far the jaraik board reaches up into the roofing that carries it. It hangs rather than stands, so it has to actually engage the roof.jaraikOverlap	0.06 mMoves no measurement	Interpolated	No source
Depth of a floor bearer.bearerDepth	0.18 mMoves no measurement	Interpolated	No source
Spacing of the bearers, and therefore the clear span of a floor plank.bearerSpacing	1.55 mIf 20% out: 0.31 m	Interpolated	No source
The furthest a split plank crosses without support in the middle. An uma’s floor is danced on: it is meant to spring, and springing is not the same as failing.plankSpan	1.80 mIf 20% out: 0.36 m	Interpolated	No source
Thickness of a floor plank.plankThickness	0.05 mMoves no measurement	Interpolated	No source
Height of the board wall of the closed room.wallHeight	2.15 mIf 20% out: 0.43 m	Interpolated	No source
Thickness of a wall board.wallThickness	0.05 mMoves no measurement	Interpolated	No source
Height of the eave over the verandas, which have no walls: the roof comes down low and that is all the wall they have.eaveHeight	1.60 mMoves no measurement	Interpolated	No source
Rise of the ridge above the wall.roofRise	3.10 mIf 20% out: 0.62 m	Interpolated	No source
Overhang of the sago-leaf roof.eaveOversail	1.15 mMoves no measurement	Interpolated	No source
Thickness of the sago-leaf roofing.roofThickness	0.14 mMoves no measurement	Interpolated	No source
Side of a household’s hearth.hearthSide	0.95 mMoves no measurement	Interpolated	No source
Height of the sand box of a hearth.hearthHeight	0.16 mMoves no measurement	Interpolated	No source
Height of the jaraik board hanging in the front veranda.jaraikHeight	1.35 mMoves no measurement	Interpolated	No source
Width of the jaraik board.jaraikWidth	1.10 mMoves no measurement	Interpolated	No source
Thickness of the jaraik board.jaraikThickness	0.06 mMoves no measurement	Interpolated	No source
Radius of ground cleared around the uma, beside the river that is its road.clearingRadius	16.00 mMoves no measurement	Interpolated	No source
Width of the river in front of the house. On Siberut the river is the road, and the house faces it.riverWidth	11.00 mMoves no measurement	Interpolated	No source
Depth of the tested joint engagement, as a share of the smaller member.jointEngagement	0.30Moves no measurement	Interpolated	No source
Zero chiefs. The rimata leads ritual and does not command, and decisions are taken together on the front veranda. No household gets a larger share, a better place, a raised seat, or an end of its own. This cannot be checked by any model: a building that genuinely has no rank and a building whose rank nobody modelled are the same model. The pack checks what can be checked and states the rest as a claim rather than a verdict.nobodyIsSenior	0Moves no measurement	Canon	Schefold, R., Lia: Das grosse Ritual auf den Mentawai-Inseln (Dietrich Reimer, Berlin, 1988).
The space is graded front to back — front veranda, closed room, back veranda — and the grade follows what is being done rather than who is doing it. A Palembang rumah limas is graded along the same axis, and there where a guest is seated is their standing. The same section, two opposite claims.gradedByActivity	1Moves no measurement	Canon	Reeves, G., “The Sakuddei of Siberut”, in Indonesian Heritage: Architecture (Archipelago Press, Singapore, 2001).
One jaraik for the whole house, hanging in the front veranda, carrying the record of what the uma has hunted. A Nias behu records one household’s feast and a Bugis timpa laja one household’s rank; this is the only record in the collection that belongs to nobody in particular.theRecordIsShared	1Moves no measurement	Canon	Schefold, R., Lia: Das grosse Ritual auf den Mentawai-Inseln (Dietrich Reimer, Berlin, 1988).
The veranda floor is danced on for turuk, so it is laid as planks over bearers with nothing under the middle of a span: it is meant to spring. That puts a limit on how far apart the bearers may be — the only figure in this pack that comes from what people do on the floor.theFloorIsDancedOn	1Moves no measurement	Canon	Reeves, G., “The Sakuddei of Siberut”, in Indonesian Heritage: Architecture (Archipelago Press, Singapore, 2001).

Bibliography

schefold-1988 · ethnography
Schefold, R., Lia: Das grosse Ritual auf den Mentawai-Inseln (Dietrich Reimer, Berlin, 1988).
reeves-2001 · reference
Reeves, G., “The Sakuddei of Siberut”, in Indonesian Heritage: Architecture (Archipelago Press, Singapore, 2001).
depdikbud-1986 · reference
Arsitektur Tradisional Daerah Sumatera Barat (Departemen Pendidikan dan Kebudayaan, Jakarta, 1986).

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.

1shareLength2.90 mlength of the house
2frontDepth1.24 mdepth of the front veranda
3backDepth0.72 mlength of the house
4roofRise0.62 mheight of the ridge
5wallHeight0.43 mheight of the ridge
6plankSpan0.36 mspan left in a floor plank
7bearerSpacing0.31 mspan left in a floor plank
8floorHeight0.21 mheight of the ridge

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 Symmetric about the plane of the ridge, x = 0 — and deliberately not along its length, because front and back are used differently
784 points; largest mirror deviation 0.00 mm.
pass
Every tenon contained in its mortise
35 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
97 parts, every one bearing on something already standing or on the ground.
pass
Mesh integrity: indices, triangles, normals
6 triangles; indices in range, none degenerate, every normal unit length.
pass
Every household has the same share
5 shares of 2.90 m each, with hearths of one size at one spacing. All this check can say is that nothing inside the model distinguishes one household from another; that nothing outside it does either is this pack’s claim rather than its verdict.
pass
The front veranda is open, with no wall at all
6.2 m of open floor facing the river: no wall, no partition, nothing across it. That is where anybody may come and where this house takes its decisions.
pass
One record, and it belongs to the house
One jaraik, on the centre line, hanging in the open veranda where everybody is — not inside any household’s share. A Nias behu records one household’s feast and a Bugis timpa laja one household’s rank; this one records nobody in particular.
pass
The planks cross the space between the bearers
The bearers stand 1.55 m apart and a plank crosses 1.80 m. This floor is danced on for turuk: it is meant to spring, and that is exactly what bounds the spacing. The spacing is the builder’s decision, the span belongs to the timber, and nothing relates them.
pass
Every part declares the dimensions it came from
97 parts, every one tagged. By least-sourced input: 0 measured, 0 canon, 97 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.

Standing the bearers further apart is what this floor wants. Its veranda is danced on: turuk asks for a long clear floor with plenty of spring in it, and fewer bearers give both. No other part objects — the posts still carry, every household’s share is still equal, the front is still open, the roof still covers the whole length. What runs out is the plank: past a point a split board no longer crosses from one bearer to the next, and a floor that springs has become a floor that gives way — the same event for everybody standing on it, and a very different one afterwards.

The house as built

pass1.55 m / 1.80 mspace between bearers · what a plank crosses

The bearers stand 1.55 m apart and a plank crosses 1.80 m. This floor is danced on for turuk: it is meant to spring, and that is exactly what bounds the spacing. The spacing is the builder’s decision, the span belongs to the timber, and nothing relates them.

Rear prow raised to 1.81 m

fail1.81 m / 1.80 mspace between bearers · what a plank crosses

the bearers stand 1.81 m apart and a plank only crosses 1.80 m

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.