3.1 Movement and Posture Fundamentals

Walking Speed

Speed controls three things simultaneously: point density, camera motion blur, and SLAM tracking stability. Move too fast and each of these degrades. The upper limit for general scanning is 3.3 ft/s (1 m/s). That is a normal walking pace, not a hurried one. In the conditions listed below, slow to 1.5 ft/s (0.5 m/s), a deliberate, unhurried pace.

Device Posture

The XGRIDS devices are calibrated and optimized for vertical operation. Tilting the device changes the relationship between the LiDAR scan plane, the visual cameras, and the IMU orientation. Excessive tilt degrades tracking and introduces artifacts that cannot be corrected in post-processing.

The posture indicator in LixelGO and LCC Scan is not a decorative element. It is a real-time alert system. Monitor it actively during scanning. When the indicator turns yellow or red, correct your posture immediately. A posture warning that persists for several seconds is affecting your data.

Scanning Distance

Distance from walls and objects directly affects depth data quality. Stay 24 to 36" (0.6 to 0.9 m) from walls for the best geometry and texture capture. The absolute minimum distance from any surface is 20" (0.5 m), approximately one forearm's length. Closer than 12" (0.3 m) to flat walls, depth data becomes unreliable and the point cloud will show distortion or gaps at those surfaces.

When scanning specific objects, maintain at least 20" (0.5 m) of clearance. In narrow spaces where this is not physically possible, slow to 1.5 ft/s (0.5 m/s) and pass through without lingering.

Holding Position and Stability

Hold the device with both hands. The goal is to eliminate micro-vibrations and sudden jerks that introduce noise into the trajectory. Think of the device as a camera on a dolly: the movement should be smooth, continuous, and controlled. Any motion that would appear jarring in footage will appear as noise or artifact in the point cloud.

• Keep both hands on the device at all times during scanning. One-handed operation increases vibration and tilt instability
• Bend your knees slightly when walking to absorb step impact, particularly on hard floors where footfall vibration transfers up through the body
• Maintain a consistent grip pressure. Shifting grip mid-scan introduces micro-movements
• When stopping briefly to change direction or observe coverage in the app, hold still. Do not sway or shift weight
• Keep personnel out of the scan path. A person walking at the same speed directly behind or in front of the operator may appear as a static object to the dynamic object removal algorithm, reducing its effectiveness

PortalCam: Bidirectional Coverage

Because the PortalCam front camera has a fixed forward orientation (unlike the 360-degree L2 Pro and K1 cameras), a single pass captures only the forward-facing half of each surface. Walk the same route forward and then in reverse to capture both directions. The return pass fills in the surfaces the front camera could not see on the first pass. For full route planning strategy, see 3.2 Route Planning.

Turning Technique

Turns are the most common source of scan artifacts for new operators. The problem is not the turn itself. It is how quickly it is executed and whether the device moves independently of the body during it.

The correct approach is to turn your entire body as a single unit: feet, torso, arms, and device all rotate together around a single vertical axis. The turn should take 1 to 2 seconds to complete, covering the full arc continuously. Never twist at the waist with the device pointing in a different direction than your hips.

• Slow to 1.5 ft/s (0.5 m/s) before beginning any turn
• Pivot on the balls of your feet rather than planting and swinging
• Keep the turn arc smooth. Do not stop partway through and restart
• Avoid turning more than 90 degrees at once in a single sweep. For 180-degree reversals in corridors, walk a small arc rather than pivoting in place
• In very tight spaces where a full arc is not possible, slow to a near-stop and complete the turn over at least 2 seconds

Why Standing Still Does Not Help

This surprises operators who come from terrestrial laser scanning, where the scanner stands still at each station and captures the entire scene from that position. Mobile SLAM does not work that way. The system requires motion to generate coverage. A stationary device scans the same geometry repeatedly from the same position, adding no new information after the first few seconds.

More critically, the IMU accumulates drift while the device is held stationary without motion to counteract it. A long pause in one place, attempting to capture more detail by standing still, can introduce positional error that would not have been present with continuous movement through the same area.

Exception: Figure-8 Technique for 3DGS

Standing completely still adds no data. However, controlled figure-8 motions from a near-stationary position do improve 3DGS visual coverage without requiring full trajectory movement. This technique is recommended in XGRIDS Best Practices for Indoor Scanning and is primarily beneficial for PortalCam and LCC Studio (3DGS) workflows. For LiDAR processing through LixelStudio, only physical movement through space generates new geometry.

• While walking: In large spaces, pause occasionally and perform a slow horizontal figure-8 motion in front of your chest for 5 to 10 seconds. This improves SLAM loop closure and surface redundancy for 3DGS reconstruction
• Stationary use: In small or featureless areas, stand still and rotate the scanner in a tight figure-8. This helps with loop closure and adds overlapping visual data that improves 3DGS density
• Vertical figure-8s: In tight rooms such as bathrooms, sweep the scanner up and down in a figure-8 pattern to capture floor and ceiling detail that a level pass would miss
• Keep the movement fluid and deliberate. Erratic hand motions introduce noise rather than useful data