Module 5 Quick Field Guide

Map Fusion Hard Limits

These constraints are not configurable. Plan within them before arriving on site.

Segment Planning Checklist

• Map the full site and divide into segments of 12 to 15 minutes each. That target leaves buffer under the 20-minute ceiling for unexpected coverage needs
• Verify the total does not exceed 10 segments and 200 minutes. A larger project splits into multiple fusion jobs, each processed separately
• Confirm all segments use the same device model. L2 Pro and K2 segments cannot be mixed in a single fusion job. If the project requires both, each model is its own fusion job, registered together afterward
• Select overlap zones with rich, stable features: furnished rooms, structured intersections, equipment areas. Avoid blank corridors, empty rooms, and featureless walls
• Plan overlap zones of 65 to 100 ft (20 to 30 m). The 50 ft (15 m) figure is the minimum; planning to it leaves no room for field adjustment
• Identify control point locations in each overlap zone before the scan. Know exactly where the device will sit for the shared marks in both segments
• Plan a fallback for RTK segments. Identify physical control point locations at each segment break in case RTK fails to reach Fixed status

Field Collection Procedure

• Each segment is a fully independent scan session. Initialize, scan, and end each segment completely before starting the next. Do not bridge segments mid-scan
• Cover the unique area of the segment fully before entering the overlap zone. Scan the overlap zone at the end of the segment, not the beginning
• Mark each planned control point location with a clear floor marker before scanning begins
• Strongest connection method: back to back without moving the device. Set the device on its metal control point base at the marker, mark the point in LixelGO, wait at least 15 seconds, end Segment 1 with the device still in place, then start Segment 2 from the same spot. After initialization, mark the same point with the identical name, lift, and rescan 50 ft (15 m) of Segment 1's area before covering new territory
• If segments are collected separately, return to the same marker and replicate device position within 4 in (10 cm) and orientation within 10 degrees of the first take
• Use the same point name in both segments, exactly, including case. A name mismatch silently discards the point in processing. Never reuse a name for a different physical location
• Review the LixelGO preview before starting the next segment. A gap found now is rescanned immediately; a gap found in processing means returning to site

Processing Reference

Processing Time Estimates

Plan approximately 20 minutes of compute time per minute of scan data. Faster CPU and more GPU memory reduce the multiplier; older hardware increases it. The processing machine must run uninterrupted for the full duration.

Hardware Impact on Processing Speed

Data Management at Scale

• A 200-minute L2 Pro or K2 project produces 200 to 270 GB of raw data. Plan storage before the project begins, not after
• The processing machine needs free disk space equal to approximately 5 times the raw data size for intermediate files. Verify before starting
• Processed output adds 50 to 100 GB depending on density settings and export format
• For point cloud review software, 32 to 64 GB of RAM is recommended for projects above 90 GB of total point cloud data
• Use LAZ format for delivery and archiving. LAZ compresses LAS by 80 to 90% with no quality loss. A 100 GB LAS file becomes approximately 10 to 20 GB
• E57 filenames must be 20 characters or shorter. Longer filenames cause silent export failure: the export appears to complete but the file is corrupt or missing
• Clip deliverables before sending. A contractor who needs the mechanical room does not need the 200 GB full-facility scan. Clip in CloudCompare or ReCap Pro first
• For files above 5 GB, avoid email and standard cloud services with upload limits. Use a large-file transfer service or a shared drive with adequate capacity

Fusion Troubleshooting Quick Reference

Full troubleshooting decision tree is in 5.6 Troubleshooting Fusion Problems. The most common failure modes are insufficient overlap depth in connection zones, mismatched control point names, and isolated segments with no link to neighbors. Catch them on site.

Critical Warnings

• No recovery Insufficient overlap cannot be fixed in processing. If two adjacent segments do not share 50 ft (15 m) of common geometry with matching features, they cannot be fused. The segment with the coverage gap must be rescanned
• No recovery An isolated segment with no connection to its neighbors cannot be fused. Every segment must link to at least one adjacent segment through RTK or matching control points. An isolated segment requires rescanning the overlap zone
• Bad data Map Fusion cannot fix drift that exists inside a segment. Fusion aligns segments to each other. It cannot correct poor loop technique within a segment. Each individual scan must be executed with proper technique before fusion is attempted
• Warning Control point consistency determines alignment quality at every join. Collect connected segments back to back without moving the device whenever possible. If returning later, replicate device position within 4 in (10 cm) and orientation within 10 degrees of the first take. In feature-poor environments the control point is the primary alignment anchor
• Warning Do not mix device models in a single fusion job. L2 Pro and K2 segments cannot be fused together. If the project requires both, each model is its own fusion job and the results are registered manually afterward
• Warning For recurring scan projects, control points must be included in the baseline scan. Control points cannot be added retroactively to completed scan data. If the baseline has no named control points in the overlap zones, future rescans cannot be fused against it. This planning decision must be made before the first scan
• Warning E57 filenames longer than 20 characters cause silent export failure. The export appears to complete but the file is corrupt. Rename projects before exporting to E57
• Warning Interrupting a fusion processing run can corrupt the project file. Use a machine that can run uninterrupted. A 200-minute project requires approximately 65 hours of continuous compute time