Contraption Builder: terrain, vehicles, Multiply, scrolling+slick palette, Bridge/Chain audit

[SethMorrowSoftware]

Summary

Enhances the Contraption Builder with terrain, drop-in vehicles, a scrolling + polished tool palette, a Multiply tool, and an audit/fix of the Bridge & Chain span tools.

🏔️ Terrain objects

A TERRAIN palette section drops static scenery the dynamic parts rest on, roll down and bump into:

Tool	What it is
Platform	A solid ledge — floors, steps, raised shelves
Ramp	A wedge for rolling/sliding, with a Facing setting (high-left or high-right) so slopes work in both horizontal directions
Hill	A rounded mound parts roll over and settle against

Each is a static polygon body (the Kit's sync skips it) and sizes, rotates, recolours, takes an adjustable grip, drags, duplicates and saves/loads like any part; joints can pin to them. Rotation/facing are baked into the polygon's points (body angle stays 0) since a static body never re-syncs. A "Terrain Run" recipe shows all three.

🚗 Drop-in vehicles

A VEHICLES section adds a Car you place like any other object: a chassis on two sprung, motorised, grippy wheels that drives off when you press Run. Its three parts share a uGroup tag, so dragging any one moves the whole car as a unit, and the grouping round-trips through save/load/reset. The "Motor Cart" recipe builds this same improved car.

⧉ Multiply tool

Alongside Duplicate, a new Multiply tool asks how many copies you want (1–50) and drops them in a tidy grid — each an independent copy (same size, colour, material, settings). Duplicate and Multiply now share one copyPart() helper that clears the group tag, so a copy of a vehicle part is a free part rather than something tied to the original car (this also fixes a latent bug where a duplicated vehicle part inherited the car's group).

📜 Scrolling + polished palette (stack stays 760 px)

The left palette is now a single vertically scrolling group, so the full tool list (SHAPES · TERRAIN · SPECIAL · VEHICLES · JOINTS) fits the original 760 px window.

• Polish: brighter section headers over hairline divider rules, left-aligned menu-style tool buttons, and a hover highlight on idle buttons (selected buttons keep their accent).
• Grouping uses the confirmed LiveCode idiom (select controls, then group; the new group is in it), wrapped in a try so a failure degrades to an un-grouped palette instead of aborting the UI build.
• raiseUI/clearUI are owner-aware so they treat the palette group as one top-level unit.

🌉 Bridge & Chain audit + fixes

The span builder is fundamentally sound (geometry, pin-chaining, world-anchoring, marker-hiding and save/load all round-trip). Fixes:

• Spans ignore Bouncy mode — segments are now always non-bouncy, so bridges/chains settle.
• Duplicating a rotated part keeps its size — copies the stored design size, not the inflated bounding box.

⚠️ Testing note

No LiveCode/OpenXTalk engine runs in the build environment, so this was validated by structural analysis (all 358 handlers + blocks balanced), symbol cross-referencing, and hand-tracing the create → edit → drag → multiply → save → load → reset round-trips. Worth a quick IDE smoke-test before merge:

1. the scrolling palette group + header rules + left-aligned/hover button styling render as intended;
2. car drag-as-a-unit + that it drives the intended direction (flip a wheel motor in the joint inspector if not);
3. the Multiply dialog/grid placement.

Kept as a draft for that reason.

🤖 Generated with Claude Code

[SethMorrowSoftware]

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