LandSnap

LandSnap uses a fixed set of representative points across the resolved component's bottom footprint: four corners, four edge midpoints, and the center. For example, a 30 m × 20 m building receives those nine samples rather than a dense scan of every square centimeter. On eligible Landscape footprints at least 5 m wide on both local axes, those target heights can estimate a rigid pitch and roll before LandSnap re-traces and refines the support pose. That physical-large contract is validated for Landscape; Mesh Terrain remains an experimental target path.

The default 0.5 cm floating and penetration threshold is an audit classification measured along the captured target normal. It is not a promise of 0.5 cm world-Z accuracy or continuous contact across an entire rigid footprint. Sub-centimeter contact can occur on compatible terrain, but a large rigid asset cannot conform to every rise and dip without deforming the asset or modifying the terrain.

The final audit re-traces the sampled footprint and records target coverage, supported-corner count, maximum sampled gap, maximum penetration, wrong-surface hits, terrain-normal deviation, and terrain-shape evidence. A mismatch remains in Needs Review for bounded repair or a deliberate project decision; it is not silently reported as a clean placement.

Experimental UE 5.8 Mesh Terrain can use a bounded, non-destructive modifier with optional padding, falloff, custom grayscale maps, and blend modes. This workflow does not alter standard Unreal Landscape heightmaps or tagged static meshes. Because it works from the actor's world-space XY bounds, an irregular foundation, stairs, or basement outline still needs an intentional custom map and project validation.

The placed object is represented by the local bounds of one resolved snap component rather than every underside vertex or polygon. Target evaluation uses Unreal collision-query ray traces, including complex collision where configured. Accurate collision that matches the visible surface is therefore essential for precise results.

LandSnap recognizes Landscape streaming proxies that belong to the same Landscape GUID. Relevant World Partition cells must still be loaded so terrain collision can be sampled. It uses Unreal's own Large World Coordinates and collision behavior, so validate representative outer-map locations before adopting strict project-wide acceptance limits.

No published result skips target-aware placement and final verification. Eligible ordinary rigid actors in AutoSnap or queued multi-actor work begin with a faster deterministic Pin-Rotate comparison; insufficient support can be challenged by a higher-accuracy path. For large jobs, process bounded groups and retain per-actor receipts. Exact-path requests accept up to 500 actor paths, while Outliner-folder requests are capped at 500 eligible actors.

LandSnapMCP provides a native 20-tool interface for status and permissions, snapping and verification, settings, AutoSnap configuration, target modes, hotkeys, repair jobs, enrollment tags, and experimental Mesh Terrain deformation. It can work with the current selection, exact object paths, or an Outliner folder, but it does not create, position, or select actors itself. AutoSnap is configured through settings; there is no separate “run AutoSnap now” command. Snap-and-verify returns structured receipts, while repair jobs progressively report their status. Mutating tools require LANDSNAP_AGENT_ENABLED=1 before Unreal Editor launches. A complete existing Needs Review queue and every internal debug value are not exposed as read-only data.

Use a general Unreal automation tool to create or position actors, then pass the resulting exact paths or folder to LandSnapMCP. Read the contact receipts, retry unresolved actors, or start progressive review repair as needed. Apply any stricter project-specific acceptance limit in that outer workflow.