Module 3 Quick Field Guide

The Numbers, By Device

These figures are not shared across the three devices. The tilt limit in particular differs, and exceeding it is the most common way an otherwise correct scan comes back degraded. Check the column for the device in your hand.

Why Speed Matters and Why Nothing Warns You

Walking too fast reduces point density and degrades visual tracking. The system needs adequate dwell time at each location to accumulate sufficient geometry. There is no in-app warning for moderate excess speed: the app flags only a severe loss of SLAM confidence, so degraded accuracy from normal overspeeding is discovered during processing or after delivery.

Figure-8 Scanning Technique

Use controlled figure-8 motions with the scanner to improve SLAM tracking and Gaussian Splat density. Keep the movement fluid and deliberate. Avoid erratic hand motions.

Starting and Stopping the Scan

These two procedures bracket every scan and take under a minute combined. Getting the second one wrong is one of the few field errors that cannot be repaired in processing.

Before You Press Start

• Check the LiDAR window and every camera lens. Clean, dry, and fog-free. Devices fog when carried between hot and cold environments, and a fogged lens looks clean at a glance
• Confirm battery. Three bars or better before leaving for the scan area. A device that force-stops mid-scan leaves you with a partial segment and no way to resume
• Set the device down on flat, stable ground for initialization. Use the supplied base or tripod. Uneven ground causes initialization failure or increased mapping thickness
• Stand clear and keep the LiDAR unobstructed. No person, bag, or vehicle in front of it, and aim it at a feature-rich area rather than an open plain, a large glass wall, or a stream of moving people
• Wait out the full 15-second static initialization on the L2 Pro and K2, and wait at least 10 seconds after the point cloud appears on the phone before lifting the device. Wait for the app to confirm initialization succeeded. Lift slowly, without a sudden movement

Before You Press Stop

The final loop closure is the one that corrects everything the session accumulated, and it is also the one most often thrown away. Walking back to the start and pressing stop does not complete it. The device needs a few seconds of stationary observation at the recognised position to run the match and redistribute the correction back across the trajectory.

• K2: return to the starting point, stand still for a full 10 seconds holding the device stable and facing the direction you originally faced, then stop recording in the app
• L2 Pro: return to the starting point and hold the same posture and orientation for several seconds before stopping. The preview visibly tightens when the match lands
• PortalCam: return to the vicinity of the starting point and stand still for several seconds before stopping
• Wait for solid green before doing anything else. A fast green flash after you stop means the file is still being written, and the flash lasts longer on a larger scene. Removing the battery or cutting power during it can truncate or lose the project

Route Structure Checklist

• Walk all main corridors first before entering any rooms. Establish the spine of the floor plan before branching
• Branch into each room from the corridor. Scan the room interior completely, then return through the same doorway you entered. Each room entry and exit is a loop closure
• Within rooms and open spaces, use a serpentine (S-shaped) or lawn-mowing pattern rather than random paths. This maximizes multi-angle coverage. Exception: extremely narrow corridors where an S-pattern is not physically possible
• Close loops continuously. Return to previously scanned areas at the end of every major space. Re-enter from the same direction and position you originally used. Retracing from the same spot facing the same direction gives SLAM the highest-confidence match
• For corridors over 164 ft (50 m) without positioning: branch into at least one room and return before reaching the far end. A straight out-and-back walk without branching accumulates uncorrected drift
• With RTK holding Fixed, corridor length stops being the constraint and the unfixed-run limit takes over: keep any continuous stretch without a fix under 328 ft (100 m) on the L2 Pro and under 164 ft (50 m) on the K2. A corridor that never drops the fix is bounded by the coordinate stream regardless of length
• Return to the initialization point at the end of the session and follow the stop procedure in Section 2. This is the final loop closure
• Do not stop the scan or create separate sessions for each room. SLAM performance depends on continuous trajectory data. Scan all rooms in a single continuous session where possible

Indoor Coverage: The Three-Pass Method

For interior spaces, three passes in a single continuous session produce far more complete coverage than one thorough pass. Each pass has a different job.

• Pass 1, wall perimeter loop. Walk slowly along the walls with the lens pointed at the opposite side of the room. Stay 1.6 to 3.3 ft (0.5 to 1 m) from the wall at 1.0 to 1.6 ft/s (0.3 to 0.5 m/s). This records the overall room structure and gives stable side-view overlap between frames. In a multi-room space, loop each room and pause longer at the doorways
• Pass 2, grid traversal. Move into the middle of the room and cross it two or three times in each direction to form a grid, lens at eye level facing your direction of travel. This captures objects in the centre of the room and the depth relationships between them, and it is what rescues weak-texture areas like white walls and open floors by adding multi-angle constraint
• Pass 3, ceiling and floor. Walk the same routes again with the lens angled up, then with it angled down, within the tilt limit for your device. This is the pass people skip and it is the one that fixes ceiling shapes, light fixtures, baseboards, floor material, and the underside of furniture

Varying your carry height between passes adds further angular diversity. Keep the height consistent within a single pass so the quality is even.

Transition Procedures

Doorways, stairwells, and confined-space exits are the highest-failure transitions in indoor scanning. The procedures below apply to all three devices unless explicitly noted otherwise. Use the speed for your device from Section 1.

Interior Door Transitions (Door Pre-Opened)

• Begin slowing 6 to 10 ft (2 to 3 m) before the doorway, down to your device's indoor speed
• Leave the door half open. A fully open door leaves one side of the frame unscanned. A half-open door captures both sides
• Turn 90 degrees sideways before stepping through the threshold. One side of the scanner faces back into the room you are leaving, one side faces into the new room
• Pause on each side of the doorway threshold until the preview shows point cloud data from both rooms. Typically a few seconds per side. Do not use a fixed timer; the required duration depends on the geometric complexity of each space
• Resume normal speed 6 to 10 ft (2 to 3 m) past the doorway

Open every door you intend to pass through before the scan starts. Opening doors mid-scan is the closed-door procedure below, and it is slower and less reliable than doing it in advance.

Closed Door Transitions

• If the door cannot be pre-opened, slowly turn so the scanner faces away from the door. Your body must block the LiDAR's line of sight to the closed door surface
• Open the door with your back to it. The scanner must not see the door opening, which introduces rapidly changing geometry that degrades SLAM tracking
• Stand sideways under the doorframe and pause until point cloud data from both rooms appears in the preview
• Enter the new room slowly and resume normal scanning

Stairwells

• Scan the landing at the base fully before beginning the ascent
• Walk up one side of the staircase, then return down the other side for coverage from both sides
• Angle the scanner slightly to capture the underside of the flight above you as you ascend, staying within the tilt limit for your device
• Scan each landing fully on both the ascent and descent
• For maximum coverage, include one pass walking sideways (crab-walking) up or down the stairwell. This gives the LiDAR a different geometric perspective on tread and riser geometry
• Budget 5 to 10 minutes for a standard three-flight stairwell with proper coverage. Complex stairwells with wide landings or multiple branches take longer. Do not rush stairwells; they are a high-failure zone and time-consuming to rescan

Exiting Confined Spaces

When exiting a confined space, align the scanner's field of view with feature-rich areas such as walls with geometry, equipment, or doorframes. Do not simply turn around and exit. Abrupt reversal without maintaining LiDAR contact with structural features causes reference loss and SLAM misalignment.

Environment-Specific Rules

Long Corridors and Tunnels

• Plan a trajectory overlap at least every 1,640 ft (500 m). On a long linear run, come back across ground you have already scanned at that interval rather than pushing straight ahead. Without it, the reconstruction layers. Where the site makes an overlap impossible, carry RTK or place relative control points beyond that distance instead
• Set the processing mode for narrow environments before you process. The setting is called Narrow Space in LixelStudio and Narrow Scene in LCC Studio. Both are in the desktop application, not in the field app. Processing tunnel or long-corridor data with the default mode produces significantly degraded results, and using the narrow mode on a normal scene can fail instead, so match the mode to the environment
• For multi-segment tunnels, plan a shared overlap point between sessions. When marking the shared point in the second scan, device position must be within 4 in (10 cm) and 10 degrees of its position in the first scan
• Minimum spacing: 16 ft (5 m) between any two shared points
• Multi-segment control point placement: the first segment gets two control points at the end only. The last segment gets two at the start only. All middle segments need two at the start and two at the end. Give the same physical location the same point ID in every segment
• Slow to your device's indoor speed or below throughout. In low-light tunnels, slower is better
• Place high-contrast targets in long featureless runs, roughly every 100 to 150 ft (30 to 45 m). Any flat, high-contrast, non-reflective marker works. The K2 ships with 30 adhesive reflective stickers suited to this. A target used this way is a SLAM anchor, not a survey point: it gives the system something reliable to match between passes and needs no surveyed coordinate. Attach a surveyed coordinate to it in processing and it becomes a ground control point instead

Reflective Surfaces (Glass and Mirrors)

• Never stop in front of glass or mirrors. Keep moving at your device's indoor speed past any reflective surface, and maintain at least 3.3 ft (1 m) distance from highly reflective objects
• Approach glass walls at an angle rather than head-on. An angled approach reduces direct reflection exposure to the LiDAR
• Keep the scanner out of mirror reflections by positioning your body between the scanner and the mirror. Stand with your back to the mirror when possible
• In bathrooms and vanities, scan low over counters or approach from side angles to avoid capturing the scanner's own reflection
• Capture mirror and glass surfaces in a single sweep. Multiple passes in front of the same reflective surface introduce artifacts
• For fully-glazed office facades, plan your route to cross glass zones rather than walk parallel to them at close range
• PortalCam is more severely affected by reflective surfaces than the L2 Pro or K2 because the visual component of its SLAM system can track reflections as false geometry

Fine wire mesh, carbon fibre, and similar transparent or highly specular materials capture poorly on every device. Where they are unavoidable, set the client's expectation before the scan rather than after the delivery.

Dark Environments

• Slow to your device's indoor speed or below in any dark area, and slower still on the PortalCam
• Bring a portable light panel and angle it forward into the area you are walking toward, not downward at the floor at your feet. SLAM is continuously matching new geometry against what it has already seen, so the upcoming area needs to be illuminated before you reach it, not after
• Camera coloring in dark environments produces poor results. Consider disabling coloring for dark spaces and re-enabling it for lit areas, or plan dark zones as separate no-color sessions
• Place high-contrast targets in dark featureless areas before scanning. Even with no surveyed coordinate, they give SLAM something to match against when visual texture is minimal

Outdoor Scanning

• Outdoor areas require consistent feature density. Do not scan open plazas or parking lots without including surrounding buildings, walls, or fixed structures in the scan path
• Use a loop-closure route, circular or serpentine, rather than a single-direction straight line
• Do not point cameras at the sun or scan into direct sunlight. Overexposure corrupts camera coloring data
• Wind affects PortalCam stability and visual tracking. In windy conditions, walk with the wind rather than against it where possible
• L2 Pro 32-300 is required for tall structures and large outdoor sites. The 16-120 and 32-120 models reach 394 ft (120 m). The K2 works to 131 ft (40 m) at low reflectivity with a 328 ft (100 m) maximum, which suits indoor and close-quarters outdoor work but not tall facades or large open exteriors

Featureless Corridors

• In narrow, uniform hallways, walk sideways (side shuffle). This keeps both walls in the LiDAR field of view simultaneously, which matters most where SLAM has few anchors
• Avoid scanning long blank walls with no features. Use diagonal paths to increase perspective variation when a side shuffle is not practical

Data Centers

Data centers are scanned repeatedly over time for change tracking, equipment audits, and capacity planning. The challenge is repetitive geometry: row after row of identical racks with no distinguishing features. Scan quality and target placement here directly affect how usable rescan comparison is.

• Speed: 1.6 ft/s (0.5 m/s) maximum in all aisles. The proximity of rack faces on both sides creates a low-feature environment throughout
• Walk every aisle. Do not skip cold aisles if hot aisles were already covered. Each aisle provides different rack face geometry
• Vary scanner height between aisles where possible. Walk one aisle at chest height and the adjacent aisle at overhead height. Change heights gradually over several feet of travel
• Complete loop closures at the end of every row by looping back through the cross-aisle at the far end before starting the next aisle
• Space targets every 100 to 165 ft (30 to 50 m) along the scan path, or one per 3 to 5 aisles. These are SLAM anchors in a repetitive-geometry environment, not survey points, unless you attach surveyed coordinates in processing
• Confirm adhesive is permitted before you place anything. Adhesive targets are what ships with the K2 and what you will most often be applying. Many facilities restrict adhesives on rack panels and some leave residue as a chargeable item. Agree the target type and placement with the facility before the visit
• Place each target where the scanner can approach within 3 to 6 ft (1 to 2 m) and circle it during the scan
• Keep targets away from hot-aisle vents and active airflow paths. Turbulent air near cooling exhaust causes vibration, and a target on a vibrating surface can shift mid-scan. Choose flat panel faces away from airflow
• Mark every target in the field app during the scan. An unmarked target is visible in the point cloud but is not used for SLAM correction or georeferencing in processing
• Place targets in the same positions as the original scan. For recurring rescans, record target locations permanently with floor coordinates or photos
• Plan rescan session boundaries so the new session covers at least 50 ft (15 m) of geometry that is also present in the session it must merge with
• Check the preview before leaving site. Visible kinks in aisle lines or discontinuities at pod boundaries indicate a tracking failure that will require recapture

Critical Warnings

• Bad data The K2 tilt limit is 15 degrees, not 20. Normal scanning must stay within 15 degrees, with a brief excursion to 30 permitted only for ground targets or full-ground coverage in a narrow area. The L2 Pro limit is 20. In RTK mode the K2 tightens to 10 degrees and the L2 Pro RTK antenna must stay within 10 degrees
• No recovery Stand still at the start point before you press stop. Ten seconds on the K2, several seconds on the L2 Pro and PortalCam. Skipping it means the final loop closure never runs and the session's accumulated drift stays in the model as layer separation, which reprocessing usually cannot fix
• No recovery No device can pause or resume a scan. If a recording stops for any reason, that segment is closed. The recovery path is Map Fusion, and Map Fusion needs overlap you must already have captured
• Bad data Moderate excess speed produces no immediate warning in the app. The app flags only a severe loss of SLAM confidence. Normal overspeeding degrades data silently and is discovered during processing or after delivery. Slow down before the environment forces you to
• Bad data Loop closure needs the same position and a return viewing angle within 40 degrees of the original. Walking back through a room facing the opposite wall satisfies neither. SLAM will not detect the overlap and drift continues accumulating
• Bad data Do not allow objects to block more than 50% of the LiDAR field of view within 3.3 ft (1 m). Sustained obstruction from your body, carried equipment, or close obstacles degrades point cloud accuracy. Reposition your carry posture or route to maintain a clear field of view
• Warning Do not push the scanner suddenly into a small enclosed space. A cabinet or void under 1.6 ft (0.5 m) deep degrades the LiDAR solution and causes data drift. Approach slowly or scan it from outside
• Warning Do not stop the scan or create separate sessions for each room. SLAM performance depends on continuous trajectory data. Segmenting by room breaks continuity and degrades alignment between spaces
• Warning Plan a trajectory overlap at least every 1,640 ft (500 m) on long linear runs. Without one the reconstruction layers. Where the site prevents it, carry RTK or place relative control points beyond that distance
• Warning Set the narrow-environment processing mode before processing a tunnel or long corridor. It is called Narrow Space in LixelStudio and Narrow Scene in LCC Studio. Using the default mode on this data degrades the result significantly, and using the narrow mode on a normal scene can fail outright
• Warning Colour needs a minimum capture duration with continuous movement. Three minutes on the K2, two on the L2 Pro. A short capture, or one where you stood still for much of it, produces poor colour no matter how good the lighting was
• Warning Stairwells take longer than their footprint suggests. A standard three-flight stairwell with correct technique requires 5 to 10 minutes. Complex stairwells with wide landings take longer. Allocate time before arriving on site
• Warning Standing completely still adds no data after the first few seconds. Only movement through space generates new geometry. Circle objects at 1.6 ft/s (0.5 m/s) instead. Controlled figure-8 motion is the one exception, and it helps visual coverage rather than geometry
• Warning Do not point cameras at the sun or direct light sources. Overexposure corrupts camera coloring data for the entire scan, not just the overexposed frames. Avoid scanning toward windows in bright sunlight
• Warning When exiting confined spaces, do not simply turn around and walk out. Maintain LiDAR line of sight to feature-rich geometry as you exit. Abrupt reversal without structural features in view causes SLAM reference loss