Comeback City 4x — three candidate layouts

Pick one. These are plan views, not built track: everything here costs seconds to change and nothing has been modelled yet. Every number was measured by scripts/track-layout-preview.mjs, the same tool that validates to 0.00% on lap length and −0.09% on lap time against the shipped race.

All four plans are drawn at ONE shared scale. The small dashed one at the end is Comeback City as it ships today. That size difference is the whole proposal: a 45-second lap with a nine-second straight to pass on, instead of an 11-second lap whose longest straight is 2.19 s.
A

Bayfront Sweep

Flow · 11,678.4 u · 44.92s lap · 16 corners · 9.22s pass window

500 u = 1.9 s

Road width along the lap, 40–70 u on every panel. Delivered 44–64 u. the pass window · the tightest corner.

One hard braking point and long corners everywhere else. Big-radius sweepers you hold a drift through, a chicane early to teach the rhythm, and a nine-second causeway across the bay that ends in the only real hairpin on the lap.

Corner census
8 sweeper · 2 hairpin · 6 turn · 2 chicane · 5L/11R
Radii
93.1-253.6 u, 0 kinks
Straights
9.22s · 4.75s · 3.88s · 2.39s
Width
44-64 u delivered · 5 levels · widest 64 u on the pass window, tightest corner 44 u · grid 60.8 u
Beats
15, one every 2.99s (min 1.8s, max 4.04s)
Elevation
peak 28 u, 16.7% max gradient, free launch off the crest
Camera
worst corner announced 1.93s (gate 0.8s), mean forward sight 2.89s

Plays like Fast, smooth, forgiving. The lap you would choose to show someone the drift mechanic.

Build cost Cheapest of the three. No new structural systems — it is the shipped bridge idea at a bigger scale.

The honest risk The least technical layout, and the one that leans hardest on the drift being fun. Its corners cluster at r110-250, so it does the least to answer "every corner is taken the same way".

Hits 22 of 24 targets. Misses: Handedness >= 33%; Road/terrain value >= 20%.

B

Downtown Deadline

Technical · 11,877.5 u · 45.68s lap · 17 corners · 9.26s pass window

500 u = 1.9 s

Road width along the lap, 40–70 u on every panel. Delivered 44–64 u. the pass window · the tightest corner.

A city block circuit: square corners, two staircase chicanes through the service streets, three switchbacks in the old town, and one Expressway where all of it either pays off or does not.

Corner census
9 sweeper · 3 hairpin · 5 turn · 3 chicane · 11L/6R
Radii
95.1-224.4 u, 0 kinks
Straights
9.26s · 3.97s · 3.2s · 1.92s
Width
44-64 u delivered · 5 levels · widest 64 u on the pass window, tightest corner 45.9 u · grid 58.8 u
Beats
16, one every 2.86s (min 1.83s, max 3.79s)
Elevation
peak 26.3 u, 17% max gradient, free launch off the crest
Camera
worst corner announced 0.82s (gate 0.8s), mean forward sight 2.72s

Plays like Busy and demanding. Rhythm is the skill; the Expressway is the reward for having found it.

Build cost Medium. No new systems, but 17 corners of downtown need 17 corners of city — it asks the most of the dressing pass.

The honest risk The busiest lap of the three and the most likely to read as work rather than flow. Two staircase corners sit at 0.82 s of announcement — over the 0.8 s gate but the tightest numbers on the sheet.

Hits 22 of 24 targets. Misses: Every corner >= 1.5 s announced; Road/terrain value >= 20%.

C

Skyline Viaduct

Set piece · 11,643.4 u · 44.78s lap · 16 corners · 9.72s pass window

500 u = 1.9 s

Road width along the lap, 40–70 u on every panel. Delivered 42–62 u. the pass window · the tightest corner.

The lap crosses itself. A viaduct climbs 2.5 km diagonally back across the infield, passes 30 units directly over the start/finish straight at its crest, launches, and drops into two stop-and-turn hairpins.

Corner census
7 sweeper · 2 hairpin · 7 turn · 2 chicane · 7L/9R
Radii
105.9-216.9 u, 0 kinks
Straights
9.72s · 5.32s · 3.02s · 2.61s
Width
42-62 u delivered · 4 levels · widest 62 u on the pass window, tightest corner 42.3 u · grid 59.3 u
Beats
15, one every 2.99s (min 2.46s, max 3.58s)
Elevation
peak 39.2 u, 13.5% max gradient, free launch off the crest
Camera
worst corner announced 1.3s (gate 0.8s), mean forward sight 2.86s

Plays like A long build to one enormous event. On lap 1 you watch the leaders go over your head; by lap 3 you are the one going over.

Build cost The most expensive. A viaduct needs a deck, an underside, supports and a road-over-road case the shipped bridge only half-solves at a quarter of the span.

The honest risk The crest hides the viaduct hairpin down to 1.3 s of announcement — legal, but the tightest thing on the candidate, and it is the corner arriving off a 30-unit drop.

Hits 22 of 24 targets. Misses: Every corner >= 1.5 s announced; Road/terrain value >= 20%.

road at true width (it varies along the lap — see the strip under each plan) left corner right corner the overtaking straight elevated road (climb / viaduct) item box boost pad ramp shortcut launch start / finish

Same scale, for reference

·

Comeback City today

Shipped · 2,889.7 u · 11.11s lap · 5 corners · 2.18s pass window

500 u = 1.9 s

Road width along the lap, 40–70 u on every panel. Delivered 45–56 u. the pass window · the tightest corner.

Drawn at the same scale as the three candidates — this is what four times longer actually looks like. Today's lap is 11.11 s, its longest straight is 2.18 s, it has 5 corners, and it throws a beat at the driver every 0.69 s. (Measured against the working tree, so it already includes the start/finish kink fix: the two r12 kinks the previewer found on the start line are gone, and the lap is 2,889.7 u rather than the 2,897 u in the design notes.)

Corner census
3 sweeper · 1 hairpin · 1 turn · 0 chicane · 2L/3R
Beats
16, one every 0.69s
Camera
worst corner announced 0.52s — under the 0.8 s gate, on 2 corners

Every target, measured

TargetA — Bayfront SweepB — Downtown DeadlineC — Skyline ViaductToday
Lap length ~11,700 u4x the shipped 2,897 u 11,678.4 u11,877.5 u11,643.4 u 2,889.7 u
Lap ~45 s / race ~135 s2-3 minute race 44.92s / 134.75s45.68s / 137.05s44.78s / 134.35s 11.11s / 33.34s
Corners 15-25MK8's range (today: 7) 161716 5
Overtaking straight 8-10 sthe single most important target (today: 2.19 s) 9.22s9.26s9.72s 2.18s
Overtaking straight >= 8 s AT TOP SPEED286 u/s, the HUD number on a passing mark (mean-speed row above is not enough) 8.38s @286 · 10.38s @2318.42s @286 · 10.42s @2318.84s @286 · 10.94s @231 1.99s @286 · 2.46s @231
Second straight 4-5 ssomewhere to use an item that is not the main zone 4.75s3.97s5.32s 1.5s
Beats 13-16, spreadthe SAME beats, not more (today: 16 every 0.70 s) 15 every 2.99s16 every 2.86s15 every 2.99s 16 every 0.69s
Sweepers >= 6a shape that holds a drift 897 3
Hairpins >= 2a shape that forces a stop-and-turn 232 1
Chicanes >= 2a shape that breaks the rhythm 232 0
Handedness >= 33%both drift directions get used 31%35%44% 40%
Radius spread80-400 u, min authored >= 72 93.1-253.695.1-224.4105.9-216.9 110.5-179.7
Three populated radius classessweeper > 200 · medium 90-140 · hairpin < 90 (floor 72) — one corner shape is one corner, however many there are 8 sweep · 3 med · 1 hair1 sweep · 3 med · 2 hair2 sweep · 1 med · 1 hair 0 sweep · 0 med · 2 hair
Delivered width rangewhat the runtime hands the camera, not what was typed (shipped CC 1.244x, Penguin Village 1.103x) 44-64 u (1.455x)44-64 u (1.455x)42-62 u (1.476x) 45-56 u (1.244x)
At most 45% of the lap at one widthshare within +/-5% of the lap median — Penguin Village sits at 82%, which is the "one boulevard" complaint 24% at 55.3 u39% at 52 u31% at 54.1 u 31% at 52.9 u
A width change you can SEE: 8 u in <= 0.6 sone kart width of narrowing, in one beat. Shipped CC does it in 0.29 s; Penguin Village never does it 0.56s at p0.6880.57s at p0.6520.56s at p0.844 0.29s at p0.184
Straight-to-hairpin width delta >= 12 uwidth coupled to the layout: the road visibly closes down where the lap does 20 u (64 -> 44)18.1 u (64 -> 45.9)19.7 u (62 -> 42.3) -2 u (54 -> 56)
No single frame signature over 30% of the lapthe judge’s actual test: is a randomly sampled frame identifiable as a specific corner (width x radius x gradient) 29% w9·straight·flat18% w8·straight·flat28% w10·straight·flat 22% w8·straight·flat
Kinks 0authored radii only — no spline artefacts 000 0
Elevation, gradient <= 18%17-18% is the shipped, proven range peak 28 u, 16.7%peak 26.3 u, 17%peak 39.2 u, 13.5% peak 20.9 u, 17%
No blind cornershard gate: 0.8 s of announcement worst 1.93sworst 0.82sworst 1.3s worst 0.52s
Every corner >= 1.5 s announced--strict-sight, the bar a NEW layout is authored to all clear2 under2 under 1 under
Sight on the overtaking straight >= 2.5 syou cannot set up a pass into road you cannot see 2.89s mean2.72s mean2.86s mean 1.65s mean
Road/terrain value >= 20%--strict-contrast; the shipped track fails this too 8% (kerb 81%)8% (kerb 81%)8% (kerb 81%) 8% (kerb 81%)

What all three miss, identically, and on purpose. The road/terrain value gate fails on every segment of every candidate for exactly the reason it fails on Comeback City today: the road solves to luminance 46.9 against a 38.5–43.4 verge, and what actually carries it in every shipped frame is the painted red/white kerb at 81% separation. These candidates borrow Comeback City's palette verbatim so their contrast verdicts are the reference build's verdicts. Authoring new palette values is the step after a layout is picked — doing it now would mean tuning three palettes to throw two away.

Handedness is topology, not tuning. A smooth convex loop turns one way; the other direction only appears where the road is concave. That is why A lands at 31% however it is tuned, why B's slalom of square corners reaches 35%, and why C — which crosses itself, so it has to turn both ways to close — gets 44% for free. If both drift directions matter, that is a reason to prefer B or C, not a number to nudge.

Width is the third axis, and it needs one runtime line before it fully lands. The blind-A/B judge picked this build 18/18 and still said all eighteen frames read as "one wide constant-radius boulevard". That is measurable: the runtime smooths the road-width table with a kernel defined as a fraction of a LAP (14 passes over 224 samples), so on a 4x lap every width transition stretches to four times its shipped world length. Authored width range went UP on all three candidates and the width you could see in a frame went DOWN — the fastest 8-unit narrowing took 0.66 / 0.57 / 1.37 s against the shipped track's 0.29 s. This round fixed the authoring half: the width step is now AT the signature corner and big enough to survive the smoother, so all three clear the gate at 0.56-0.57 s. The other half is one line in the build — scale the width table's resolution with lap length so the kernel stays ~35 world units — which takes the same three layouts to 0.16 s and doubles the width contrast inside a frame. Whoever builds the picked layout should do that first; it is quantified in section 8 of docs/TRACK_CANDIDATES.md.

What happens next. Pick a letter. Only then: author the palette against --strict-contrast, place the coin rows (~30, scaling with length, still free — one InstancedMesh), and build geometry. Re-run the previewer afterwards so the JSON report lands in the record next to the frames.

Full sheet: a-bayfrontFull sheet: b-downtownFull sheet: c-skylineToday’s track