3.6 Scan Plan Tool

Step 1: Scope and Constraints

Answer these before site arrival. They are not optional.

• Total scan area in square feet or square meters, by floor or zone.
• Deliverable: point cloud, 3DGS, BIM model, ATIS.cloud project, measurement-grade survey, or a combination.
• Required absolute accuracy: 3DGS visualization (no absolute reference), 3 cm RMSE georeferenced (RTK or GCPs), or survey-grade (extensive GCPs).
• Baseline or rescan. Rescans must match prior session structure: same targets, route, boundaries.
• Access window: hours per day, total days, escort requirements, after-hours availability.
• Access restrictions: secure zones, sensitive equipment, photography limits, adhesive limits.
• Devices: L2 Pro for large facades and long range, K2 for indoor and close-quarters work, PortalCam if 3DGS-only is the deliverable.
• Site contact and the escalation path if something goes wrong during the scan.

Step 2: Route and Session Planning

Turn the scope into an executable route: session boundaries, startup points, and the order of areas.

Session and Fusion Limits

A session is one continuous scan from startup to completion. Multiple sessions join later with Map Fusion, which has hard limits.

Longer individual scans are allowed but need stronger processing hardware (more RAM and a stronger GPU).

Session Boundary Rules

• Each session starts and ends at the same physical location with at least 15 m (50 ft) of overlap. Less than that aligns inconsistently.
• Place boundaries at structural features easy to return to: cross-aisles, distinctive doorways, intersections. Featureless boundaries are harder to align.
• Multi-floor: one session per floor, joined at stairwells, not elevators.
• Multi-day: each day is at least one session. Plan day-to-day overlap explicitly.

Startup Point

• Initialize in a feature-rich area with at least 3 visible walls or large features. Lobbies, doorway thresholds, and corners work well.
• Choose a point you can return to cleanly. The final loop closure within 5 to 10 m (15 to 30 ft) of startup is the most important in any session.
• For RTK, reach Fixed outdoors in clear sky, then carry the device to the indoor start. The position is preserved during the carry.

Step 3: Georeferencing and Control Point Placement

If the deliverable needs absolute coordinates, plan GCP placement before the scan. Number and spacing depend on device and area.

GCP Spacing

Space GCPs so no two consecutive points exceed the device's unfixed-RTK tolerance.

GCP Surveying

• Surveyed coordinates required. Without them a control point is an anchor target, useful for SLAM but not for absolute georeferencing.
• Same coordinate system as the RTK base if RTK is used. Mixing systems forces transformation and loses precision.
• Document the coordinate system explicitly: datum, projection, zone. Future rescans must reuse it.
• Survey method by accuracy need: total station for survey-grade, RTK rover for general georeferencing, building geometry for relative-only deliverables.

Coverage Pattern

• Distribute GCPs in a triangle, not a line. A line does not constrain rotation; a triangle does.
• Place one near startup and one near the final loop closure point.
• Add 20 percent redundancy over the minimum spacing, so a marking or survey failure does not break the dataset.

Step 4: Anchor Target Placement

Anchor targets differ from GCPs. GCPs provide georeferencing; anchor targets give SLAM high-contrast features to track where natural geometry is uniform. Some projects need both, some only one.

When to Place Anchor Targets

• Long featureless corridors over 60 m (200 ft).
• Dark environments where visual tracking is unreliable.
• Repetitive geometry: data centers, uniform-racked warehouses, tunnels.
• Multi-session projects where Map Fusion depends on shared anchors.
• Rescan engagements where target continuity drives change detection.

Target Spacing

Plan placement every 30 to 45 m (100 to 150 ft) along the path. Closer in higher-challenge zones (very dark, very repetitive), wider where some natural features exist.

Placement Checklist

• Scanner can approach within 1 to 2 m (3 to 6 ft) and circle each target during the scan.
• Each target is on a stable surface, not a vibrating panel, near vents, or on a flexible substrate.
• Each target's position is documented (photo with rack ID or room reference) before the scan.
• For rescans, target positions match the baseline documentation.
• Adhesive policy verified with the operator before sticker placement.
• Removal plan in place: targets and tape collected before site exit.

Step 5: Time and Resource Estimation

Estimates that miss reality by more than 25 percent cause access overruns, fatigue, or incomplete coverage. Build from per-zone baselines, not a single area ratio.

Baseline Scanning Time

These assume 1.6 ft/s average pace, single-pass coverage, and no significant transitions or environmental challenges. Use as starting points, then adjust.

Adjustment Factors

• Multiply by 1.5 to 2.0 for many transitions (multi-floor, many small rooms, stairwell-heavy layouts).
• Multiply by 2.5 to 3.0 for three-pass coverage in detailed 3DGS spaces.
• Add 30 to 60 minutes per session for setup, startup-point selection, RTK Fixed, and final checks.
• Add target time: 3 to 5 minutes per anchor target, 10 to 15 minutes per surveyed GCP.
• Add escort coordination at secure sites: 15 to 30 minutes per access window.
• Plan a 5-minute rest every 45 to 60 minutes of active scanning. Hour-3 posture produces less recoverable data than a planned break.

Step 6: Risk Review

Review the plan against known failure modes before arrival. Catching them in planning is far cheaper than after the fact.

• Compound-challenge zones identified (dark and featureless, reflective and outdoor) with extra time and specific technique.
• Session boundaries verified: within hardware tolerance, each with at least 15 m (50 ft) overlap.
• GCP placement verified: spacing within device tolerance, triangular distribution, redundancy, coordinate system documented.
• Anchor target inventory confirmed: enough targets, with adhesive verified for sticker placement on non-ferromagnetic surfaces.
• Site contacts current: primary, escalation, and after-hours numbers confirmed in the last 30 days.
• Access window fits the estimate: scan time plus setup, breaks, and contingency, with 25 percent buffer.
• Deliverable expectations documented: format, accuracy, ATIS.cloud publishing, BIM handoff, timeline confirmed in writing.
• Equipment ready: devices charged, batteries swapped, mobile devices charged with LixelGO or LCC Scan installed and tested, processing machine has free disk space.