Basketball Hoop

A showcase piece, not an example, and the first in the sports category. It builds a procedural in-ground basketball goal standing on a patch of driveway court:

• a two-pour concrete pad, 5.2 × 6.6 m and 100 mm thick, split by an expansion joint with a sunk sealant strip; the second pour sits 1.5 mm under the first;
• a painted court in faded, worn paint: a baseline, a filled key with lane lines, a block and three ticks each side, a free-throw line and circle, and part of a three-point arc cut off by the pad's edges;
• two pebbled size-7 basketballs with black seams, one on the court and one by the pole's foot, each resting on the concrete;
• a base plate sunk into the slab with four gussets and four anchor bolts set through it into the concrete, each with a washer and a hex nut;
• a 6 in square steel pole swept in one piece from inside the plate, through an S-shaped gooseneck with a welded gusset web inside each bend, up into the mast behind the board;
• a square navy pad on the pole, split into three panels by seam grooves, with a hook-and-loop flap closing it up one corner;
• a collar carrying two diagonal support braces up to the board's lower back rail;
• two bolted clamp sleeves and standoffs carrying the board on a rail-and-stile back frame;
• a backboard in a 50 mm satin aluminium frame, with a navy edge pad along its bottom, a painted red border and a painted shooter's square;
• a regulation orange rim on a breakaway mount: a tapered bracket, a hinge barrel across its heel and a spring housing on top, bolted through a flange plate, two struts and twelve welded net hooks;
• a white cord net: twelve loops hung on the hooks, 24 strands that cross in a tapered diamond mesh, and a knot at each of the 72 crossings.

The pole, gooseneck and mast are one sweep of a rounded-square section, because a bent bar is one bar. The straight run of the gooseneck is solved from the mast's offset (gooseneck_path()), so the mast always lands behind the standoffs. Each bend web is outlined from the bend's own inner arc (bend_webs()), a bite inside the tube. Each brace is a tube between two named stations. Its foot sits in the middle of the collar wall and its head sits inside the lower rail. Pad, collar, clamps and cap are the pole section grown by an offset, so every sleeve is a true parallel of it.

The rim follows regulation: the top of the ring is 3.05 m above the court surface, its inside diameter is 0.457 m, and its inner edge sits 0.151 m off the board face. The bottom line of the shooter's square has its top edge level with the rim. Each net loop is a torus threaded across the hook eye. Its cord passes through the eye and bears 1.5 mm into the hook's lower inside, so the loop hangs on the hook rather than floating near it.

The court markings are a driveway layout, not regulation: a 2.7 m lane, the free-throw line 2.98 m off the board face, a 4.2 m arc about the basket centre. They are scaled to the pad, so the key, circle and arc all fit on it.

Every paint line is a strip sunk into its own slab and standing proud of it. Groups that overlap never share a plane: each has its own top and sink (baseline 2.2 / 2.6 mm, lane lines 1.8 / 2.0, free-throw line 2.2 / 2.6, key fill 1.0 / 1.4, lane marks and circle 1.4 / 3.0, arc 1.8 / 2.0). Lines stop 8 mm short of the joint gap, and the free-throw circle is 6 mm wider than the lane so its ends are clear of the lane lines' side faces. The base plate is sunk 4 mm into the slab rather than laid on it, so its underside never lands on the slab top. Each ball is a UV sphere bearing 2 mm into the slab; its four seams are tori just under its surface, turned so none runs through the contact point.

Paint on the board is thin annuli sunk 1 mm into the board. They stand proud by different amounts (border 0.8 mm, square 1.2 mm), and the border is 44 mm wide so its inner edge clears the square's bottom line. The two bolt heads on each clamp face stand 1 mm apart so their caps never share a plane.

Bevels run once per material with material= set. On the first run, without it, the board's chamfer faces took slot 0 and the board shell classified as steel.

Shading follows what each part is. Round stock (ring, cord, balls, braces) is smooth-shaded. Chamfers, material boundaries and bends over 35° stay sharp, and so does a flat face meeting a much narrower facet, so the pole's flats read flat and its corner fillets read round. The steel is near-black satin powder coat and the frame satin aluminium, each with a studio reflection term in the material (after espresso-machine), so neither reads as grey plastic on the dark stage.

It asserts budget conformance of the generated result. It does not witness an API contract. "It rendered without error" is not a check.

Composes skills mesh-editing-and-bmesh, bake-high-to-low, depsgraph-and-evaluated-data, engine-export-presets, and snippets bake_normal_high_to_low.py, setup_bake_target_image.py, lod_chain.py / decimate_to_budget.py, convex_hull_collider.py, export_preset_unity.py (helpers copied inline, not imported).

Intended size: 5.2 × 6.6 m court pad; 1.83 × 1.05 m board with its bottom 2.90 m above the court; pole axis 1.22 m behind the board face. The outer AABB is 5.200 × 6.600 × 4.050 m; the pad sets the footprint, and the pole cap on the 100 mm slab sets the height. The convex collider wraps the pad and the hoop together (44 tris).

Budgets#

Every budget is declared as a named constant. Every gate recomputes its value from the mesh, materials, UVs, evaluated LOD, collider, or export file.

DECIMATE COLLAPSE triangle counts are not identical across Blender series, so the LOD gate is a ratio band, not an exact count. Bake pixels are stochastic, so the bake gate is has_data plus operator FINISHED, not byte-identity. Construction uses no RNG; two default runs print identical measurements.

Hygiene#

Recomputed from the generated mesh, not asserted about the script.

Joint fit, net seat, rim, court and assembly#

Falsifiers#

Each falsifier violates one named budget. Every one was run on 5.2.1 and exited its declared code.

--drop-net and --tilt-rim move whole sub-assemblies. The net drops without its hooks, and the rim tilts with its hooks and net about the flange, so only the budget each one targets can see the change. --drop-net, --float-ball and --float-paint also split the assembly, so the net-seat, ball-seat and paint checks all run before the component check (20). --short-bolts keeps each bolt in the plate, so it stays connected and only the embedment fails. --loose-pad needs a part held by one joint only: the pad (with its flap) touches nothing but the pole.

Run#

blender --background --python basketball_hoop.py --
blender --background --python basketball_hoop.py -- --skip-decimate
blender --background --python basketball_hoop.py -- --stray-vert
blender --background --python basketball_hoop.py -- --lift-z
blender --background --python basketball_hoop.py -- --short-brace
blender --background --python basketball_hoop.py -- --drop-net
blender --background --python basketball_hoop.py -- --tilt-rim
blender --background --python basketball_hoop.py -- --float-ball
blender --background --python basketball_hoop.py -- --short-bolts
blender --background --python basketball_hoop.py -- --float-paint
blender --background --python basketball_hoop.py -- --loose-pad
blender --background --python basketball_hoop.py -- --output hoop.png

Smoke passes no flags.

The hero turns the piece HERO_YAW_DEG (−172°) and shoots it with a 70 mm lens from 20 m, a little above the board, so the court runs toward the camera and the key, circle and arc read at thumbnail size while the board and net read face-on. The long lens keeps the near corner of the pad from swelling. The key light's spread keeps it on the hoop and court instead of the near floor, and a warm wedge washes the back wall on the right.

Exit codes#

File-local. 9 is a valid check code. 10 is reserved for gallery_framing.check_framing on the --output path. 15–19 are the hygiene and joint-fit family. 20–23 are file-local. 24 is the asset-quality floor on the render path: check_asset_quality returns 11, which this piece already spends on the collider ceiling, so the call site remaps it.