6.2 Scan Splitting and Multi-Session Workflows

The Three Limits That Decide Segment Length

Plan segments at 12 to 15 minutes and keep every capture under 20 minutes. That single rule satisfies every limit below, on any supported workstation, in either processing pipeline.

Three unrelated systems impose a duration limit, and they are frequently confused with each other because two of them happen to produce the number 90. Read them as three separate ceilings, because the one that binds your job depends on your hardware and your deliverable.

Why 20 minutes is the number to plan against

If a capture will only ever be reconstructed in LCC Studio, no per-segment time limit applies to it and the workstation is the only real constraint. But the L3, the L2 Pro, and the K2 feed both pipelines from the same raw scan, and a decision to run the point cloud through LixelStudio Map Fusion later is often made after the crew has left. LixelStudio caps each capture session in a fusion at under 20 minutes, and there is no way to shorten a capture after the fact.

Planning under 20 minutes therefore costs nothing and keeps both doors open. Alpine plans at 12 to 15 minutes, which leaves room for unexpected coverage without approaching any limit.

When to Split

A planned split is better than a forced one in every respect. It produces smaller files, gives processing manageable segments, and creates natural checkpoints for quality review. A forced split, taken when the battery warning sounds or the device stops recording, lands wherever you happen to be standing, which is usually the worst place for it.

• Battery change. The most common reason. Plan the split before the charge drops below 20 percent. Do not scan to shutdown.
• Workstation memory. Match segment length to the machine that will process the data, using the tiers in Section 1. A segment your hardware cannot hold is not a long segment, it is a failed job.
• Logical site divisions. Floor boundaries, fire doors, building wings, and parking structures are natural split points that also produce cleaner scan organization and easier client review.
• Drift risk in complex geometry. Long scans in featureless or repetitive environments accumulate more trajectory drift than short ones. Splitting at transition zones caps the drift exposure carried by any one segment.
• Deliverable structure. If the client wants floor-by-floor models rather than one continuous model, split on the boundary they want rather than fusing and cutting later.

Where to Split: Choosing Good Transition Points

Map Fusion joins segments by matching geometry in their overlap zones. A split at a point where the next segment begins with nothing recognizable from the previous one will fail or misalign, and neither is correctable after the crew leaves.

Characteristics of a good split point

• Feature-rich geometry visible from several angles: a corridor intersection, an equipment cluster, a lobby with columns.
• A spot where the device can rest on its base on a hard, level surface, so the next segment can start without moving it.
• Not in the middle of a long featureless corridor, and not against a blank wall.
• Not in an open outdoor area with little vertical structure in LiDAR range.
• With at least 50 ft (15 m) of planned overlap on each side of the split.

Minimum overlap

Segments must share at least 50 ft (15 m) of scanned ground for Map Fusion to align them, and 65 to 100 ft (20 to 30 m) is the target that leaves field margin. The second segment must cover ground the first segment also covered, traveled in a way that captures the geometry from comparable angles.

Executing a Clean Split

The procedure is the same whether you are changing a battery, taking a break, or ending a floor. The order matters, and step 3 is the one that loses data when it is skipped.

1. Scan past the split point by at least 50 ft (15 m). Keep moving at normal pace through the overlap zone. This data is what the fusion algorithm uses to connect the segments, and it is the only chance to capture it.
2. Mark the connection before you stop. If the segment is running without reliable RTK, set the device down at the shared control point, add the point in the field app, and wait 15 seconds so the scanner captures a complete cloud around it. Use the identical name in the neighbouring segment. Names are case-sensitive and a mismatch fails silently.
3. Tap Stop, then wait out the write process before touching anything. Stopping does not end the job. The scanner then writes the project file to internal storage, which takes 30 to 60 seconds and longer after a long capture. The green indicator flashes rapidly while it writes and goes solid green when it is done. Do not power off, remove the battery, or disconnect during that window. An interrupted write corrupts the project file and the capture is not recoverable.
4. Document the split location. Note the room, landmark, or position where the segment ended, and photograph any control point you placed. If the next segment cannot start immediately in place, this is what lets you find the identical overlap position, sometimes hours later.
5. Start the next segment from the split point without moving the device. If the seam uses a control point, mark the same name after initialization, wait 10 seconds, then lift slowly. Walk back through at least 50 ft (15 m) of the previous segment's coverage, then continue into new ground. Hold still through initialization; movement during it corrupts the reference frame for the whole segment.
6. Vary the line of travel through the overlap zone. Retracing the previous segment's exact path gives the aligner one viewpoint on the shared geometry. Walking a slightly different line, or pausing at a perpendicular angle, supplies geometry from different viewpoints and measurably improves alignment confidence.

Naming Conventions for Multi-Session Projects

With eight segments across a three-floor building coming into a fusion, disorganized names make it impossible to verify which segments belong to which job and in what order, and the software will not catch the mistake for you.

Use the pattern ClientName_SiteName_Date_FloorOrZone_SegmentNumber. For example: Breck_Library_20260205_FL1_S01, Breck_Library_20260205_FL1_S02, Breck_Library_20260205_FL2_S01.

Scan and project folder paths carry their own constraint: no spaces anywhere in the path, and letters, digits, hyphens, underscores and periods only.

Multi-Day Projects

Fusion assumes the segments describe the same building.

• Re-establish RTK before scanning on day two. RTK state does not carry forward from a previous session. Confirm a Fixed solution before the first segment of the day. L3 RTK is built in and survey-grade; the L2 Pro uses the clip-on module; K2 RTK is built in.
• Leave ground control markers in place until every segment that references them is captured. A marker moved between days is worse than a marker that was never placed, because the fusion will still use it.
• Hold the naming scheme exactly. Control point names are case-sensitive across sessions. A point named fp01 on day one and FP01 on day two reads as two different points, and the connection fails with no error shown.
• Re-check scanner settings at the start of each day. Confirm any session-specific option used in the prior segment, and confirm the scan mode if the device offers a choice that locks at scan start.
• Capture fused segments under consistent lighting where you can. Segments captured under very different lighting produce visible seams in a 3DGS reconstruction even when the geometry aligns correctly.

Once the segments are captured, the fusion itself runs at the workstation. For the point cloud pipeline see 8.3 Map Fusion; for the 3DGS pipeline see 9.3 Map Fusion. Data organization before either one is on 6.6 Data Preparation.