XGRIDS Pro Guide™ / Module 3: Field Technique

Module 3 Quick Field Guide

Speed limits, posture rules, route structures, transition procedures, and environment-specific technique in one reference page.

Section 1

Speed and Posture Reference

Condition
Speed
Notes
General scanning, feature-rich environments
3.3 ft/s (1 m/s) max
Standard pace. Smooth and continuous.
Corridors, open rooms, low-feature areas
1.6 ft/s (0.5 m/s)
SLAM drift accelerates in featureless spaces.
Door and stairwell transitions
1.6 ft/s (0.5 m/s)
Begin slowing 6 to 10 ft (2 to 3 m) before.
Reflective surfaces, dark areas
1.6 ft/s (0.5 m/s)
Keep moving. Never stop in front of glass.
Data center aisles
1.6 ft/s (0.5 m/s) max
Treat as indoor hallway throughout.
Equipment circles
1.6 ft/s (0.5 m/s)
Circle at 3 to 10 ft (1 to 3 m) distance.
Tunnels and mine shafts
1.6 ft/s (0.5 m/s) or below
Max 1,600 ft (500 m) per segment.

Scanning Distance

Parameter
Distance
Notes
Optimal wall distance
24 to 36 in (0.6 to 0.9 m)
Best geometry and texture quality.
Minimum from any surface
20 in (0.5 m)
One forearm length.
Absolute minimum (flat walls)
12 in (0.3 m)
Closer produces unreliable depth data.
Reflective surfaces
3.3 ft (1 m)
Increased distance for glass and mirrors.
L2 Pro Posture
  • Hold vertically at chest height. Tilt no more than 20 degrees from vertical.
  • Never scan horizontally. LiDAR needs vertical geometry to track.
  • Lens orientation: In open areas, 1 lens left, 1 lens right. In corridors and doorways, rotate 90 degrees so 1 lens faces your direction of travel.
K1 Posture
  • Tilt forward 15 to 20 degrees so LiDAR scans the ground approximately 15 ft (5 m) ahead.
  • Do not exceed 20 degrees in normal walking. Temporary tilt to 30 degrees permitted for ground targets but must not be sustained.
  • Lens orientation same as L2 Pro. Rotate 90 degrees in corridors and doorways.
General Movement Rules
  • When turning, rotate continuously over 1 to 2 seconds. No snapping or quick pivots.
  • At corners, maintain LiDAR line of sight to both walls (the wall you are leaving and the wall you are approaching).
  • Height changes must be gradual over 10 to 15 ft (3 to 5 m). Viewing angle difference must not exceed 40 degrees.
  • Do not allow objects to block more than 50% of LiDAR FOV within 3.3 ft (1 m) for sustained periods. Includes your own body.
  • Do not stand still. Circle objects at 1.6 ft/s (0.5 m/s). SLAM needs trajectory movement, not rotation from a fixed point.
  • Turn 90 degrees sideways through every doorway for all devices.
PortalCam-Specific Posture
  • Tilt range: -60 to +60 degrees from vertical. Wider than L2 Pro/K1 due to multi-camera coverage.
  • Front camera must face your walking direction. Unlike L2 Pro/K1, the PortalCam is sensitive to device orientation.
  • Bidirectional coverage required: walk the route forward, then in reverse. A single pass captures only forward-facing surfaces.
  • Avoid sudden lighting changes mid-scan. PortalCam's 3DGS output is more sensitive to visual quality than point cloud output.
  • Do not point at light sources, windows, or the sun.

Figure-8 Scanning Technique

Use controlled, fluid figure-8 motions to improve SLAM tracking and 3DGS density.

Scenario
Technique
Walking through large spaces
Pause and perform a slow horizontal figure-8 for 5 to 10 seconds, then resume.
Small or featureless areas
Stand and rotate the scanner in a tight figure-8 for loop closure and surface redundancy.
Tight rooms (bathrooms, closets)
Sweep in a vertical figure-8 to capture floor and ceiling detail.

Exception to the standing-still rule: figure-8 motion from a near-stationary position improves 3DGS coverage, even though it does not add new LiDAR geometry. For LiDAR-only processing (LixelStudio), only physical movement generates new data.

Section 2

Route Structure Checklist

Standard Indoor Route (Backbone-First)
  • Walk all main corridors first before entering rooms. Establish the spine before branching.
  • Branch into each room from the corridor. Scan completely, return through the same doorway. Each entry and exit is a loop closure.
  • Use serpentine (S-shaped) patterns within rooms and open spaces. Exception: corridors too narrow for an S-pattern.
  • Close loops continuously. Return to previously scanned areas from the same direction and position you originally used.
  • Corridors over 160 ft (50 m) without RTK: branch into at least one room and return before reaching the far end. With RTK Fixed, corridors up to 500 ft (150 m) are viable.
  • Return to within 15 to 30 ft (5 to 10 m) of your initialization point at session end, from a similar angle to your starting position.

Do not create separate sessions for each room. Scan all rooms in one continuous session. Start at the main entry, loop through all rooms, finish where you started.

Loop closure requires a return angle within 40 degrees of your original. Returning from the opposite direction does not trigger SLAM loop detection. Drift remains uncorrected.

Section 3

Transition Procedures

Interior Door Transitions (Door Pre-Opened)

Door Entry Sequence
  • Begin slowing 6 to 10 ft (2 to 3 m) before the doorway. Target: 1.6 ft/s (0.5 m/s).
  • Leave the door half open. Fully open leaves one side of the frame unscanned.
  • Turn 90 degrees sideways before stepping through.
  • Pause on each side of the threshold until the preview shows data from both rooms.
  • Resume normal speed 6 to 10 ft (2 to 3 m) past the doorway.

Closed Door Transitions

Closed Door Procedure
  • Turn so the scanner faces away from the door. Your body blocks LiDAR's view of the closed surface.
  • Open the door with your back to it. The scanner must not see the door moving.
  • Stand sideways under the doorframe and pause until data from both rooms appears.
  • Enter slowly and resume normal scanning.

Stairwells

Stairwell Procedure
  • Scan the base landing fully before ascending.
  • Walk up one side, return down the other for bidirectional coverage.
  • Angle the scanner to capture the underside of the flight above. Stay within 30 degrees of vertical.
  • Scan each landing fully on both ascent and descent.
  • For maximum coverage, include one sideways (crab-walk) pass for tread and riser geometry.
  • Budget 5 to 10 minutes per standard three-flight stairwell. Do not rush. High-failure zone.

Exiting Confined Spaces

Align the scanner with feature-rich geometry (walls, equipment, doorframes) when exiting. Do not simply reverse direction. Abrupt reversal without features in view causes SLAM reference loss.

Section 4

Environment-Specific Rules

Tunnels and Long Corridors
  • Maximum 1,600 ft (500 m) per segment. Divide longer runs before starting.
  • Enable Narrow Scene mode in LixelStudio for processing. Default mode produces degraded results on tunnel data.
  • Shared overlap points between segments: device position within 4 in (10 cm) and 10 degrees of Segment 1.
  • Minimum 15 ft (5 m) between any 2 shared points.
  • Control point placement: first segment: 2 at end. Last segment: 2 at start. Middle segments: 2 at start + 2 at end. Same point ID across segments.
  • Speed: 1.6 ft/s (0.5 m/s) or below throughout.
  • Place XGRIDS scan targets every 100 to 150 ft (30 to 45 m) as SLAM anchors. No surveyed coordinates needed. To also use as GCPs, supply coordinates in LixelStudio during processing.
Reflective and Glass Surfaces
  • Never stop in front of glass or mirrors. Maintain 3.3 ft (1 m) distance from reflective objects.
  • Approach glass walls at an angle, not head-on.
  • Position your body between the scanner and mirrors. Back to the mirror when possible.
  • In bathrooms and vanities, scan low or from side angles to avoid capturing the scanner's reflection.
  • Single sweep past mirror/glass surfaces. Multiple passes introduce artifacts.
  • For glazed facades, cross glass zones rather than walking parallel at close range.
  • PortalCam is more affected because visual SLAM tracks reflections as false geometry.
Dark and Low-Light Areas
  • Speed: 1.6 ft/s (0.5 m/s) or below.
  • Bring a portable light panel. Angle it forward into the area ahead, not at the floor at your feet.
  • Consider disabling coloring for dark zones or planning them as separate no-color sessions.
  • Place XGRIDS scan targets in dark featureless areas as high-contrast SLAM anchors.
Outdoor Environments
  • Do not scan open plazas or parking lots without surrounding structures in the scan path.
  • Do not point cameras at the sun. Overexposure corrupts coloring data.
  • Wind affects PortalCam stability. Walk with the wind where possible.
  • L2 Pro 32-300 required for tall structures and large outdoor sites. 16-120 and 32-120 limited to 120 m range.
Narrow and Featureless Hallways
  • Walk sideways (side shuffle) to keep both walls in LiDAR FOV simultaneously.
  • Use diagonal paths when a side shuffle is not practical.

Three-Pass Capture Strategy. For maximum interior coverage, use 3 passes at different heights in a single continuous session. Pass 1 at ~5 ft: primary SLAM loop and wall geometry. Pass 2 at ~7 to 8 ft: ceilings, light fixtures. Pass 3 at ~2 to 3 ft: baseboards, floor textures, under-furniture detail. Especially effective for 3DGS output.

Section 5

Data Centers

The challenge: repetitive geometry with no distinguishing features. Target placement directly affects rescan comparison quality.

Data Center Scanning Rules
  • Speed: 1.6 ft/s (0.5 m/s) maximum in all aisles.
  • Walk every aisle. Do not skip cold aisles if hot aisles were covered. Each provides different rack geometry.
  • Vary scanner height between aisles. Chest height in one, overhead in the adjacent. Change heights gradually.
  • Loop closures at the end of every row through the cross-aisle before starting the next.
Target Placement
  • Space XGRIDS targets every 100 to 165 ft (30 to 50 m), or one per 3 to 5 aisles.
  • Place where the scanner can approach within 3 to 6 ft (1 to 2 m) and circle during the scan.
  • Keep away from hot-aisle vents. Magnetic attachment to a rack panel preferred.
  • Mark every target in LixelGO. Unmarked targets are visible but not used for correction.
Rescan Alignment
  • Place targets in the same positions as the original scan. Record locations permanently.
  • Rescan sessions must cover at least 50 ft (15 m) of shared geometry with the session they merge into.
  • Check the preview before leaving. Kinks in aisle lines or discontinuities at pod boundaries indicate tracking failure.
Section 6

Critical Warnings

  • Bad data Excess speed produces no warning in the app. LixelGO alerts only on severe SLAM confidence drops. Normal excess speed degrades data silently. Discovered during processing or after delivery.
  • Bad data Loop closure requires return within 40 degrees of original viewing angle. Returning from the opposite direction does not trigger detection. Drift remains uncorrected.
  • Bad data Do not block more than 50% of LiDAR FOV within 3.3 ft (1 m). Includes your body and carried equipment.
  • Warning Do not create separate sessions for each room. Scan all rooms in one continuous session.
  • Warning Tunnels over 1,600 ft (500 m) must be segmented before scanning.
  • Warning Enable Narrow Scene mode for tunnel/corridor processing. Default mode produces degraded results. Setting is in LixelStudio, not LixelGO.
  • Warning Stairwells: 5 to 10 minutes per three-flight. High-failure zone. Allocate time before arriving on site.
  • Warning Standing still adds no data. Circle objects at 0.5 m/s. Exception: figure-8 motion improves 3DGS coverage.
  • Warning Do not point cameras at the sun or direct light sources. Corrupts coloring data for the entire scan.
  • Warning When exiting confined spaces, maintain LiDAR contact with structural features. No abrupt reversals.
Previous: Module 2 2.5 Critical Basics Next 3.1 Movement and Posture

©2026 Alpine Reality Capture LLC  •  XGRIDS Pro Guide™  •  Site Disclaimer