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. Segments up to 20 minutes are permitted, but targeting 12 to 15 minutes gives you buffer for unexpected coverage needs
• Verify the total does not exceed 10 segments and 200 minutes. A project exceeding these limits requires splitting into multiple fusion jobs, each processed separately
• Confirm all segments use the same device model. L2 Pro, K2, and K1 segments cannot be mixed in a single fusion job. If the project requires multiple device models, each model is its own fusion job and the results are registered manually afterward
• Select overlap zones with rich, stable features: furnished rooms, structured intersections, equipment areas. Avoid blank corridors, empty rooms, and featureless walls as overlap zones. The algorithm needs geometry to match
• Plan overlap zones of 65 to 100 ft (20 to 30 m), not exactly 50 ft. The 50 ft (15 m) figure is the minimum. Planning to that minimum leaves no room for field adjustment
• Identify control point locations in each overlap zone before the scan. Know exactly where you will stand for the shared marks in both segments
• Plan a fallback for RTK segments. Even on RTK-planned projects, identify physical control point locations at each segment break in case RTK fails to achieve 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 attempt to 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 control points in the overlap zone before ending the segment. These points must be physically revisited and marked in the next segment as well
• Review the LixelGO preview before starting the next segment. Check coverage in the unique area and in the overlap zone. A gap found now can be rescanned immediately. A gap found during processing requires returning to site
• Place physical XGRIDS sticker targets at each control point location before scanning begins
• In Segment 1, approach the marker, mark it in LixelGO, and note your exact position and body orientation when marking. Photograph the scene if needed
• In Segment 2, return to the same marker and replicate your position within 4 in (10 cm) and orientation within 10 degrees of the Segment 1 take. This is a field best practice that produces the most reliable fusion results
• Use the same point name in both segments, exactly, including case. A name mismatch causes the control point to be silently discarded in processing

Processing Reference

Processing Time Estimates

At Medium Quality settings in LixelStudio v4.0, plan approximately 20 minutes of compute time per minute of scan data. Adjust for your hardware: 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 to accommodate intermediate files generated during SLAM optimization and fusion. 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 in LAZ
• E57 filenames must be 20 characters or shorter. LixelStudio's E57 export fails silently on longer filenames. The export appears to complete but the file is corrupt or missing. Apply this limit before exporting
• Clip deliverables before sending. Delivering a 200 GB full-facility scan to a contractor who needs only the mechanical room is not useful delivery regardless of data quality. Clip to the required area 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. Replicate device position within 4 in (10 cm) and orientation within 10 degrees of the Segment 1 take. In feature-poor environments where surrounding geometry cannot compensate, the control point becomes the primary alignment anchor. Know exactly where you stood in Segment 1 before marking the same point in Segment 2
• Warning Do not mix device models in a single fusion job. L2 Pro, K2, and K1 segments cannot be fused together. If the project requires multiple device models, 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 was collected without named control points in the overlap zones, future rescans cannot be fused against it using the control point connection method. This is a planning decision that must be made before the first scan
• Warning E57 filenames longer than 20 characters cause silent export failure. LixelStudio will appear to complete the export but the file will be corrupt. Rename projects before exporting to E57
• Warning Interrupting a fusion processing run can corrupt the project file. Set a machine that can run uninterrupted. A 200-minute project at Medium Quality requires approximately 65 hours of continuous compute time