Settings and saves

NXSand splits engine settings from element physics. Changing either does not reset the active save slot. Brush radius in settings.json applies globally (including after slot load).

Save locations

Platform	Path
Switch	sdmc:/switch/nxsand/
Desktop	./nxsand_save/

Legacy folders (nxengine / nxengine_save) migrate forward on first launch when the new folder is empty.

Files

File	Purpose
settings.json	Engine, display, performance, visuals, controls, accessibility, debug
physics.json	Per-element tunables (Element Settings)
slot0.json … slot2.json	World grids (JSON + base64), brush state, timestamp
launch.log	Fatal / startup diagnostics (Switch, when writable)

Engine settings (settings.json)

Key groups:

• Display — orientation (Auto / Landscape / Portrait), safe areas.
• Performance — sim resolution preset, substeps, active tiles (Off / Conservative / Aggressive), dynamic resolution, sim shader (fragment vs compute), idle sleep.
• Visuals — palette mode (Pretty / Fast / Classic / debug IDs), ambient occlusion, flicker, grain, upscale filter, bloom level. Loaded from visuals; legacy render object is accepted. Missing visuals.flicker defaults to off.
• Controls — brush radius (flushed immediately when changed in menus).

Heavy GPU changes (sim resize, backend switch) defer one frame after leaving Engine Performance (schedulePendingHeavySettingsFlush) so Back does not stall on reinit.

Disk writes are queued: one file per frame on tab back, menu exit, or shutdown (Switch matches desktop). Desktop shows a save-in-progress overlay during writes.

Element settings (physics.json)

Tunables map to the PhysicsBlock UBO (source/sim/physics_gpu.hpp) and shaders/sim_common.glsl. Examples: water flow rates, plant growth, acid corrode, gunpowder chain, salt dissolve.

Presets (Battery Saver / Balanced / Quality) adjust sim size and substeps on Switch; see Switch performance matrix.

Save / load flow

Slot format and GPU upload details: Architecture → Persistence.