Region Selection Tool Guide¶

Draw regions in Scene View to query objects spatially.

Activation¶

Keyboard shortcut: Shift+R in Scene View

Status: Mode label appears at top-left of viewport. Press Escape to cancel/deactivate.

Drawing Modes (Q/W/E/R)¶

Lasso Mode (Q)¶

• Click repeatedly to trace outline
• Preview line follows cursor
• Enter to close and confirm

Rectangle Mode (W)¶

• Click first corner
• Move mouse to second corner (preview shows quad)
• Click second corner to finalize
• Always axis-aligned (no rotation)

Circle Mode (E)¶

• Click once for center
• Drag outward to set radius
• Release mouse to confirm

PointByPoint Mode (R)¶

• Click to add vertex
• Space to confirm point (visual feedback)
• Click again for next vertex
• Enter to close polygon
• Escape to cancel

Modifiers¶

Visual Feedback¶

Drawing: - White lines show polygon edges - Blue circles mark vertices - Red cross at center

Objects inside: - Green quad highlights objects within region - Count shown: "[region_id or inline] (X objects)"

Querying Regions¶

Query from Code¶

# Get all objects in polygon region (inline vertices)
result = await spatial_query(action="objects_in_polygon", vertices="x1,z1;x2,z2;x3,z3", cap=50)

# Or use saved region ID
result = await spatial_query(action="objects_in_polygon", region_id="region-uuid-123", component="Collider", cap=50)

Parameters: - action — must be "objects_in_polygon" - vertices — semicolon-separated pairs "x1,z1;x2,z2;..." (>=3 pairs; optional if using region_id) - region_id — UUID to load from cache - component — filter by component type name (empty = all) - cap — result limit (default 50, max 200)

From Chat¶

Region chips work in the LLM prompt:

[region:region-id-123]Selected Area[/region]

Query this region for all Colliders:
→ LLM calls query_state internally

Click the chip to frame the region in Scene View.

Persistence¶

Regions are automatically saved to Library/MCP_Regions.json (gitignored):

• Max regions: 20 (older ones auto-evict when limit exceeded)
• Survives: Domain reload, editor restart
• Auto-delete: Regions older than 24h (on next load)

Common Patterns¶

Select enemies for batch edit:

# 1. Draw region around enemies with Shift+R
# 2. Query region
objects = await spatial_query(action="objects_in_polygon", region_id="<saved-id>", component="Enemy")
# 3. Batch update health (for each object path in results)
# Use batch for efficiency
await batch("""
set_property path=Enemy1 component=Health prop=MaxHP value=100
set_property path=Enemy2 component=Health prop=MaxHP value=100
""")

Spatial assertions in playtest:

VAL $boss_arena 100,0,0
# (region drawn previously with Shift+R)
ASSERT_NEAR Player Boss 10.0  # Within arena bounds

Visual selection from chat: - Draw region with Shift+R - Chat references region chip - Click chip to focus in viewport

Limitations¶

• Regions are 2D (XZ plane only; Y-independent)
• Point-in-polygon uses ray-casting (O(n) per query)
• Component filter is exact match (case-sensitive)
• Regions are Edit Mode only (Play Mode queries rejected)

Troubleshooting¶

See also: Scene Tools for spatial queries, Batch Reference for batch operations.