Base Building and More

Building System Overhaul + Critical Save/Load Fix

May 21, 2026

Big update. The building system is now fully featured, the bug that made packaged builds regenerate terrain with the wrong seed on load is gone, and the periodic 2-second hitching is gone. Highest-impact patch since the survivor system landed.

New Features

Full Snap-Together Building System

[]Five piece types all snap together intelligently: floor, wall, half-wall, roof tile, roof peak []Q/E rotation cycles through the four cardinal snap edges of any target piece []Mouse wheel in-place flip — 90° per click for floors (4 orientations), 180° per click for walls/roofs (2 orientations). Rotates around the piece's center so position stays put while orientation mirrors. Use for triangular walls, asymmetric pieces, or just picking which side faces inward. []Smart per-piece snap behavior:
[]Floors tile edge-to-edge, extend end-to-end, and overhang on wall edges []Walls stack above, below, side-to-side, and extend end-to-end along their long axis []Half-walls stack via cube-edge math: two half-walls = one full wall height with no gap. Mix-and-match half + full walls works automatically. []Roofs rest on top of floor/wall with the eave-edge sitting on the wall; tile end-to-end up or down the slope with 45° rise = run; tile side-to-side on the same slope plane []Roof peaks follow the same rules as roof tiles

[]Cursor-driven direction — point at the side of a wall where you want a roof, hover the floor edge you want a wall on, etc. Less fiddly than fixed snap-point cycling.

New Recipes

[]Stick Floor []Stick Wall []Stick Roof []Stick Roof Peak []Stick Wall (Half) []Survivor Campfire (placed near recruited survivors)

Critical Bug Fixes

Saved Worlds Now Load Correctly in Packaged Builds

The painful one: saving a world and reloading it in the packaged game would regenerate terrain with a different seed. Players would respawn standing on their flattened build area at sea level with the rest of the world towering 100m above them.

Root cause was diagnosed through layered logging: the seed parameter was being applied to the shared height-graph asset, but the world uses a stamp that has its own separate parameter override map which takes precedence. The stamp's override was untouched, so the runtime read the cooked default seed.

Now the seed is applied to the stamp directly, cooked assets are force-loaded ahead of seed application, the voxel runtime auto-create is disabled so our seed-applied CreateRuntime is the only one that fires, and the stamp is told to refresh after the parameter change.

Player Auto-Possesses Their Saved Character on Load

The spectator camera was being placed 50m above the saved pawn after load, leaving the player floating as a sky-cam instead of in their character. Now the game finds the pawn matching the saved player-controlled GUID and possesses it once terrain is ready, so you resume IN your character at the saved location.

Mobs and Survivors Stop Spawning in Trees

The ground trace for new spawns would stop at the first hit, which was often a PCG-spawned tree or rock — so creatures would appear perched in canopies. Spawns now filter trace hits to actual voxel terrain only.

Building Snap Bugs

[]Half-wall vertical stacking: two half-walls used to leave a 50cm gap. Replaced fixed-offset math with cube-edge-to-cube-edge math; works for any wall height and supports mixed half-on-full stacking. []Cursor in the lower half of a half-wall used to be treated as "below the wall," which broke stack-above. Partition now uses the cube's actual center. []Wall-to-wall end-to-end snap (extending a wall into a line) wasn't implemented — every wall-on-wall went through vertical stack. Now lines up cleanly when the cursor is past the wall's end. []Stack-below was fallback-only and almost never won — couldn't reliably place a wall under another wall. Now fires as primary when the cursor is clearly below the target's cube bottom. []Roof Z direction was inverted: clicking the peak side spawned the next roof below instead of above. Flipped. []Roof tile pitch used inflated 45°-projection bounding-box numbers instead of the underlying cube size, so end-to-end tiling was 7cm off. Now uses the actual cube dimension.
• Side-to-side roof snap from below (looking up at the underside) now works.

Performance

2-Second Hitching Eliminated

Diagnostics showed sustained 3fps for ~300ms every 2 seconds — the periodic terrain modification sweep was walking every actor in the world (5,400+) to find ~30 instanced-mesh components, then checking 10,000+ individual foliage instances per zone.

Three optimizations:

[]Iterate instanced-mesh components directly instead of walking every actor (6× reduction in iteration count) []Use the component's own spatial index to query overlapping instances per zone (drops 10,000 per-instance checks to dozens)
• Skip zones that aren't within 25m of any local player — foliage that far away isn't visible anyway

Sweep cost dropped from a frame-time-dominating spike to negligible. No more periodic hitching during play.

Logging Quieter in Placement Mode

The per-target snap-evaluation log was firing ~2,000 lines per second while in placement mode, driving log buffer flushes that contributed to micro-stutters. Demoted to verbose level (still available for debugging via console: Log LogMOFramework Verbose). Actual snap-fire logs (when something matches) stay visible.

Notes

[]If you have an existing save from a previous build, the seed will load correctly now — you don't need to start over. []Building pieces are currently 1-stick recipes for testing. Material costs and quality tiers come in a later patch.
• Modding tooling: added Tools/ue_json_utils.py for editing DataTable JSON exports with proper UE encoding detection.