Castle

Castle

extensions/castle/ builds a moated brick castle from a plan. It draws the castle with brick, slate, water, lawn and woods under the sun of a date and an hour. The extension ships the plan of Wijnendale Castle at Torhout in West Flanders, Belgium. Each figure of a plan says how it was found. The page Castle analysis holds the engineering checks that read the same plan. The page Landscape stands the castle in mountains and woods, with a scanned church beside it.

The picture comes from examples/wijnendale.mojo. It takes about half a minute on 24 CPU threads. The sun is where it stands over Torhout at 15:00 local time on 19 October 2026. The moat is Clearwater's water, and the castle and the wood are reflected in it. The same castle is a scan of 3.65 million splats in Virtual scans. That scan draws in milliseconds and can be walked through.

.venv/bin/mojo run -I . examples/wijnendale.mojo out/wijnendale.png

Modules

Module	What it gives
castle/kinds	Material, RoofKind and Provenance, each a type with is_valid
castle/plan	CastlePlan, Tower, Wing, Gate, QuayWall, Moat, Bridge and the point and band tools
castle/wijnendale	wijnendale_plan, the survey's footprint and the castle's place
castle/masonry	Masonry and historic_brick, the strength and stiffness of brickwork by EN 1996-1-1
castle/parts	Walls with windows cut through them, plinths, crowns, dormers and spires, as triangles
castle/render	castle_meshes: the mesh view of a plan, one mesh for each material
castle/textures	Maps of brick, stone and slate from the real sizes of a unit
castle/look	castle_look: a physically based material for each surface
castle/trees	Trees grown from a branch skeleton, with cards of leaves, and shrubs
castle/scene	build_castle_scene, aim_sun and draw_castle
castle/sky, reflect	The sky and its clouds, and the mirror image in the water
castle/sun, shadow	The sun over a site, and the shadows of the towers; see Castle analysis
castle/landscape, landscape_mesh	The ground from the castle's meadow to the mountains, and its triangles; see Landscape
castle/forest, crowns	The woods of a landscape by altitude and distance, and the crowns of far trees; see Landscape

The plan

A plan is in a flat frame in meters, x east and y north of an origin that the plan names. Levels are meters above a datum. Every length is a Length64, every angle an Angle64, and every part carries a Provenance that says how its dimensions were found.

Part	What it is
Tower	A round tower with a wall to a height and a roof over it: a spire or a crown
Wing	A band of constant width along an axis, with a gable roof whose ridge follows it. Its corners are mitered
Gate	A rectangular block with a flat top, at a heading
QuayWall	The wall that holds the island's earth at the edge of the moat
Moat	The water: an outline, a level and a depth
Bridge	A run of semicircular brick arches on piers

CastlePlan.check refuses a plan whose parts do not stand together. footprint_overlap says how well the solids reproduce the outline that a survey gave: the area they share over the area they cover together.

Provenance is one of four kinds. A plan that relies on a figure can tell a survey from a guess.

Provenance	Meaning
SURVEYED	From a survey: the outline of the building and of the moat
MEASURED	Fitted to survey data: a wing, the gate and a tower
DOCUMENTED	From a document
ESTIMATED	A guess from a photograph or from the style: the depth of the moat, the quay wall, the bridge's arches, the proportions of the roofs

Wijnendale

The Flemish heritage inventory (record 87491) and the history of the castle give the facts.

• About 1276 to 1278: Count Guy of Dampierre has a stone castle built. It is round and moated, with eleven half-round towers and a heavy gate tower.
• From 1833: the Matthieu family rebuilds the castle.
• 1877 to 1878: the Brussels architect Felix Laureys builds the pseudo-medieval gate tower with its crenellations. He extends the right wing with a round donjon.
• 1982: the castle becomes a protected monument.

The inventory gives no dimensions. The plan comes from open data of Digitaal Vlaanderen. See THIRD-PARTY-NOTICES.md.

• The outline of the building and the outline of the moat are from the Flemish large scale reference map, GRB. The building has 99 corners. The coordinates are Belgian Lambert 72. The moat outline is simplified by 0.25 m.
• The heights are from the Digital Height Model of Flanders II. It is a 1 m raster of the surface and the terrain from an airborne laser scan. The water surface is the flat 34.31 m that the scan returns over the moat.
• The towers are circles fitted to the arcs of the surveyed outline. The wings and the gate are the bands and the rectangle that best cover it. They reproduce 96 percent of the surveyed area.

The plan holds these parts: the donjon and seven turrets, the north and the south wing, the gate tower, the moat and the bridge. It also holds the low wall of the courtyard with its four quay towers.

The mesh view

castle_meshes(plan, default_view()) gives one geometry for each material: brick, stone, slate, water, lawn, gravel, foliage, glass, wood, metal and bark. A wall is a plate with the openings cut through it, so a window has a reveal as deep as the wall is thick. A window has a stone surround, a sill, a frame, a mullion and a pane set back in the opening. A round wall is a ring of plates, and a crown is a ring of corbels under a parapet of merlons. A wing has dormers, chimneys and a leaded ridge. The ground is a grid of heights: the bed of the moat, its banks, the island and the meadow.

The textures are procedural, and use the real sizes of a unit:

• A brick is 210 by 65 mm with a 10 mm joint, in running bond.
• A block of stone is 600 by 300 mm.
• A slate is 300 by 400 mm, laid with a 120 mm exposure.

The normals come from a height field that the same pattern makes. So a joint is a groove, and a slate has an edge that throws a shadow. castle_look gives each surface a metallic-roughness material.

The scene

var plan = wijnendale_plan()
var renderer = castle_renderer(800, 1000)
var castle = build_castle_scene(plan, default_settings(), eye_east, eye_north, 45.0)
aim_sun(castle, renderer, toward_the_sun)      # a unit vector, y up and z south
var image = draw_castle(castle, renderer, camera, 0.55, 5)

A picture is made in four steps.

1. The renderer draws the scene with the sky as a prefiltered environment, and soft shadows from a lamp that stands where the sun does.
2. The sky and its cumulus are painted where the renderer drew only the clear ground.
3. The water of the moat is Clearwater's, composed into the picture where it is nearest.
4. The castle and the wood are reflected in the water, in the share that Fresnel's law gives.

aim_sun redirects the lamp and prefilters the sky again. A low sun is dimmer and redder, because its light crosses more of the air. The woods are an illustration: the survey does not say where the trees are. They follow the photograph, a meadow open to the north, broadleaf trees close to the moat and dark conifers behind. No tree stands within a radius that the caller gives of a place, such as the camera.

SceneSettings trades quality for time. It sets the size of a tile of material, of the sky's cube and of the shadow map. It also sets whether the woods are grown, and the spacing of the ground grid. default_settings() gives 512 texel tiles, a 128 texel sky, a 4096 texel shadow map, woods and a 1 m grid.

Limits

• The plan has no interiors. A wall is a plate and the inside is not modeled.
• The openings are a regular pattern of the style, not a survey of the windows.
• A figure that is ESTIMATED is a guess. The roofs' proportions, the plinth, the depth of the moat, the quay wall and the bridge's arches come from a photograph.
• The renderer draws in software, with supersampling and a shadow map. A picture takes about half a minute. To walk through the castle, draw its scan instead.