XGRIDS Pro Guide™ / Module 5: Project Scale & Map Fusion

5.7 Map Fusion Connection Visual

How scan segments link together through RTK, control points, or both, and the two configurations that always fail.

Section 1

How Segments Connect

Every segment in a fusion project must link to at least one neighbor through valid RTK or matching control points. If any segment has no connection, it is excluded from the fused result. Use this diagram to verify your connection plan before going to site. Full detail is in 5.1 Fundamentals and 5.3 Collection.

Section 2

Fusion Connection Patterns

Section 3

Connection Types Legend

Element

Meaning

Blue segment

Valid RTK data recorded during the scan. Provides global coordinates independently.

Orange segment

No RTK. Relies entirely on shared control points to connect to neighbors.

Hatched zone

Overlap area between adjacent segments. Minimum 50 ft (15 m); plan 65 to 100 ft (20 to 30 m).

CP marker

A control point marked in the field during the scan. Must be marked in both segments with identical names.

CP link

Two segments sharing a matching-name control point. One matching point per adjacent pair is the software requirement. Plan two, and use three where alignment quality matters. Narrow Space tunnel work uses two per set.

Red X or dashed red

Invalid configuration. The segment cannot be fused and must be recollected.

Section 4

The Three Connection Methods

RTK Connection

HowBoth segments independently record valid RTK data. The shared coordinate system aligns them automatically.

RequiresFixed status (not Float or Single Point) throughout each segment. Each segment needs at least 100 ft (30 m) of effective RTK coverage.

OutputGlobal coordinates.

Best forOutdoor projects with clear sky view.

RiskTree canopy, urban canyons, and building shadows degrade RTK to Float without warning.

Control Point Connection

HowThe same physical location is marked in both segments with an identical name. The algorithm matches the names to establish alignment.

RequiresAt least one matching-name point per adjacent pair. Plan two, and use three where alignment quality matters. Names are case-sensitive.

PlacementSet the device on the ground at the marker. On the L2 Pro and K2, replicate position within 4 in (10 cm) and orientation within 10 degrees between sessions. On the PortalCam, within 1.6 ft (0.5 m), 20 degrees, and about 4 in (10 cm) in height.

OutputRelative coordinates unless RTK is present elsewhere in the chain.

Best forIndoor projects and any site where RTK is unavailable.

RiskName mismatches fail silently. No error is displayed; the segment simply does not fuse.

Hybrid Connection

HowSome pairs connect through RTK, others through control points. The algorithm uses whichever method is available per pair.

RequiresEvery adjacent pair has at least one valid method. Mixing methods across the project is fine.

OutputGlobal coordinates if any segment in the chain carries valid RTK.

Best forMixed indoor and outdoor projects, which is the most common real-world case.

Invalid: No Connection

CauseA segment has neither valid RTK nor a shared control point with any neighbor.

ResultExcluded from the fused output. Overlap alone does not admit a segment.

FixRecollect the segment with a valid connection method in place. Control cannot be added after capture.

Both pipelines support the same three connection methods, and both accept the K2. LixelStudio Map Fusion covers the L2 Pro and K2 with current firmware, producing point clouds. LCC Studio Map Fusion covers the L2 Pro, K2, and PortalCam, producing 3DGS models. The per-segment duration limits differ between them, so size a job against the pipeline that will process it. See 9.3 LCC Studio Map Fusion and 10.2 FAQ.

PortalCam control point requirements are stricter. The specs above reflect L2 Pro and K2 practice. PortalCam Map Fusion requires at least 3 control points per segment, distributed in an L-shaped pattern rather than a straight line, at least 33 ft (10 m) apart. The PortalCam has no RTK, so control points are its only connection method. See 7.2 Advanced Scanning Features and 7.4 Map Fusion Collection.

Section 5

Field Planning Rules

Every segment needs at least one connection. A segment connected to nothing is excluded from the fusion, regardless of its own quality.
Plan control points even on RTK projects. RTK drops to Float without warning under canopy and near structures. A marked control point at each segment break is the fallback that saves the job.
Overlap is required in addition to the connection method. Minimum 50 ft (15 m) of shared geometry, planned at 65 to 100 ft (20 to 30 m). RTK or control points alone will not fuse segments that do not physically overlap.
Each segment needs unique coverage. Complete overlap fails. The overlap zone is the bridge between segments, not the whole content of a segment.
Place overlaps in feature-rich areas. Open spaces, long corridors, smooth tunnels, monochrome or dark areas, and reflective surfaces all degrade the match. A furnished room or a structured intersection is a far better bridge than a blank hallway.
Walk the overlap in a zigzag rather than a straight line. The extra viewing angles strengthen the match in the connection zone.
Control point names are case-sensitive and must be unique per location. CP01 and cp01 are different points, and reusing a name for a different physical location is a documented failure condition.
Maximum 10 segments and 200 minutes per fusion job. Larger projects split into multiple fusion jobs, registered together afterward.

Fusion control points and survey GCPs are different things. The control points in this diagram connect segments to each other and produce relative coordinates. Coordinate transformation to a real-world system is a separate step requiring at least 3 surveyed absolute control points across the project, not on a straight line. See 10.8 Accuracy Reference.

Section 6

What You Get After Fusion

Point Cloud (LixelStudio)

One unified dataset spanning all input segments, exportable as LAS, LAZ, PLY, or E57, with RCP available through the built-in converter for Autodesk workflows. Coordinates are global if any segment carried valid RTK, relative otherwise.

3DGS (LCC Studio)

One fused model from the L2 Pro, K2, or PortalCam, viewable in LCC Viewer and publishable as a browser link for clients. Export as LCC2, LCC, or PLY. Projects that exceed the 10-segment or 200-minute limits split into multiple fusion jobs and are assembled afterward.

Processing procedure is in 5.4 Map Fusion Processing. Troubleshooting for failed fusions is in 5.6 Troubleshooting Fusion Problems.

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