Advanced topics

Define polygon filter

The polygon filter restricts an import to a geometrically defined area. Available for DGM, CityGML, and GeoShape; not for DOP (the orthophoto is always placed in full).

The Polygon filter dialog offers five sources:

In the Free edition polygons are limited to max. 4 lines; more complex polygons, the GeoJSON path, and the line-style path are Pro-only.

Draw the polygon on top of the DOP first

Recommended approach for the standard case:

1. Import the DOP first — the orthophoto provides a visual reference.
2. In the site plan, draw a closed detail line around the area of interest (polygon, pentagon, trapezoid — any closed polyline).
3. On the DGM and CityGML imports, choose the polygon source "From detail or model lines" and pick the line you just drew.

Advantage: the polygon is drawn visually on top of the orthophoto and therefore spatially precise. Both following imports clip to exactly the same area.

Concave polygons (DGM note)

Concave polygons reliably filter points (points outside are reliably removed). Revit's Toposolid triangulation, however, fills the concave notch with terrain triangles, so the outer outline of a Toposolid becomes convex-hull-like. Workaround: split the concave polygon into multiple convex sub-pieces and run a separate DGM import per piece.

Persistence

The polygon is stored per import. A re-import of the same file with the same polygon is possible without re-running the picker — the polygon is adopted automatically.

Re-import

A second import of an already-imported file into the same project does not silently overwrite — it asks:

• Replace existing data — the old elements are deleted and replaced with the current result. Pre-fill of the dialogs uses the previous choices.
• Import despite drift (if drift was detected) / Import anyway — the second import is added next to the first. Useful for comparison studies.
• Cancel.

Re-import inherits the Survey-Point/anchor decision of the first import automatically and does not ask again.

Drift detection (Pro)

If the Survey Point has been manually moved or the project has been rotated between two imports, GeoBridge detects the deviation on the next import and asks. The thresholds are tight enough to fire only on actual interventions — minimal numerical noise is ignored.

Survey Point drift (tolerance: 1 mm)

Dialog title: Survey Point drift detected.

The Survey Point has moved by 0.420 m since the last geo-import. Existing imports and this import would be offset in the shared frame.

Choices:

• Restore Survey Point — SP jumps back to the persisted state from the last import. Internal element positions do not change, but dimensions relative to the SP show the old state. Existing geo imports are once again congruent with this import.
• Import despite drift — drift remains. Existing imports and this import will appear offset in the shared frame.
• Cancel — the import is not executed.

Angle drift (tolerance: 1e-6 rad ≈ 0.0000573°)

Dialog title: Project North rotation detected since last import.

Project North has changed by 12.50° since the last geo-import.

The import is placed using the current Project North rotation — this matches existing imports if the rotation was made via "Manage > Rotate Project North" (Revit rotates all elements along).

If rotated by other means ("Rotate True North" or direct edit of the PBP angle field), please cancel, manually rotate Project North back, and restart the import.

Choices:

• Continue with current Project North — uses the live rotation for the transform; matches the "Rotate Project North" workflow.
• Cancel — when the rotation was done differently, Cancel is the right choice.

Recommended workflow for Project-North rotation

1. Open a Floor Plan view, set view orientation to "Project North".
2. Manage ribbon → Rotate Project North.
3. Define pivot points or enter the angle.

Other paths (Rotate True North, direct PBP angle edit) cause drift on later imports and the drift dialog can only be answered with "Cancel" in those cases.

Multi-tile with edge-merge (Pro, DGM)

When neighbouring DGM tiles are imported together (multi-selection in the file dialog), Pro inspects the shared tile edges and aligns identical elevation values, so the finished terrain has no visible seams. The detection adapts to the cell size of the data set (DGM1 to DGM50) and to overlapping tile regions.

Free imports tiles independently side-by-side without edge-merge — visible seams are possible if neighbouring tiles have minimally different values along their shared edge.

Event Manager (new in 1.1)

The Event Manager is the central overview of every GeoBridge action that has shaped a project — imports, convention declarations, and prefix toggles. It sits in the GeoBridge ribbon as its own button and opens a table-style window listing all persisted events plus three state-aware actions at the top.

Status row

The top row of the Event Manager shows the project's current UTM convention:

Set convention (Pro)

Active exactly when the status is "not declared yet" — typically after manually setting the Survey Point via the DOP-ribbon "Set SP" button without a subsequent file import.

A click opens a small picker: UTM zone (1–60, pre-filled from the SP magnitude) plus with/without-prefix (same heuristic). A magnitude warning fires if the input does not match the SP position.

OK writes the convention as an event into the project — without moving the Survey Point. Subsequent file imports inherit the convention silently and the prefix dialog is skipped.

Toggle UTM prefix (Pro)

Active exactly when the convention is already declared and every import event refers to the same UTM zone. Flips the project from "with prefix zone N" to "without prefix zone N" or vice versa — moving the Survey Point by ±N million metres (N = zone) so all already-imported geometry stays in place (it just sits in the other convention in the shared frame).

Before flipping, a before/after confirmation dialog shows the concrete SP coordinates in both conventions. Switching between zones (e.g. 32 → 33) is not possible — that would require a Helmert transformation. Cross-zone mismatches are caught by GeoBridge at import time.

The button is greyed out when:

• no import events exist — there's nothing whose convention could be flipped. Import first, or declare the convention via "Declare convention…".
• the active convention is not applicable — e.g. the anchor was set without a UTM zone. "Declare convention…" supplies the missing zone.
• the import history contains mixed zones — tooltip reads "Mixed zones". Happens when earlier imports persisted e.g. zone 32 and a later import landed with zone 33 (typically: the wrong zone was confirmed in the prefix dialog by accident). A plain flip would be ambiguous — which zone wins? GeoBridge refuses the operation rather than silently overwriting one of the two zones. Recovery: identify the offending import events (see the table below — the "Zone prefix" column shows the value per event), delete the bad import (remove the elements on the Revit side), or have the event record cleaned up manually (contact support).

Event table

Each row is one persisted event. Columns: time, kind (Import / TranslatePrefix / DeclarePrefix), plugin, source file, source EPSG, prefix convention at the time of the event, anchoring mode, SP shared coordinates in metres, PBP internal, project north angle, number of elements belonging to the import, live state (Live / Orphan).

Orphan rows mark imports whose elements have been manually deleted from the project — the event record persists even though the geometry is gone. Useful forensic info if you suspect imports accidentally vanished.

Diagnostic logs (for support)

When an import behaves unexpectedly or geometry lands in the wrong place, GeoBridge writes a diagnostic log to %LOCALAPPDATA%\GeoBridge\diagnostics. The file is a plain-text dump of the most important input values (SP shared, source EPSG, pixel size, bounding box corners, project north angle, etc.) and is intended for support requests.

When contacting support@lichtbus.de, just attach the most recent relevant log — speeds up diagnosis significantly. The logs contain no personal data and no geometry content; only the geo-setup values.

Errors are written separately to %LOCALAPPDATA%\GeoBridge\errors (stack trace + context). The About dialog → "Export support ZIP" packs both directories into a single ZIP file.

Pristine rotation — rotating Project North before the first import

If the Revit project is fresh (no anchor yet) but Project North has already been rotated ("Manage → Rotate Project North"), GeoBridge detects this on the first file import and asks. Background: with no anchor set, the Survey Point sits at (0, 0, 0) — the rotation has no reference point, so imported geometry appears differently in plan-north versus geo-north views.

The Pre-rotation detected dialog offers three paths:

1. Anchor SP from source and import — GeoBridge anchors the Survey Point at the source file's SW corner, keeps the current Project North rotation, and continues the import normally. Recommended for most cases.
2. Cancel — set SP manually first — closes the dialog and the import. You can then use "Set SP" in the DOP ribbon to anchor at a custom point (e.g. a building corner or a survey nail), and re-run the import afterwards. Recommended when the model should rotate around a specific point rather than the source file's SW corner.
3. Cancel (standard cancel button) — same as option 2 but without the "next step" hint.

For rotated pristine projects, option 2 (set SP first) is the right choice when the desired anchor point does not coincide with the SW corner of the first file — typical for architectural workflows where the project is rotated around a building axis or a handover point.

DWG coordination body

Recommended workflow for collaboration with landscape architects who deliver DWG plans:

1. One time: GeoBridge imports DOP/DGM/CityGML using the Reference Point anchor variant, where the reference point is a clearly marked real-world point (e.g. a survey nail, a building corner, a manhole cover).
2. From the Revit model, a "coordination body" DWG is exported with this point as origin and handed over to the landscape architect.
3. The landscape architect aligns their AutoCAD geometry to the coordination body.
4. All later DWG deliveries from this landscape architect can be linked in Revit via "Auto — Origin to Origin" and snap into place without further adjustment.

The coordination body workflow works in both editions.

Adopting an existing project anchor (Pro)

The flip side of the coordination-body workflow: the Revit project arrives with the Survey Point already set. Typical scenarios:

• Masterfile from the project lead with a correctly georeferenced coordinate system
• IFC link from an architecture office that carries a geo-reference in the header
• DWG handover from the landscape architect linked via "Auto — Origin to Origin" which adopted the SP from the source DWG
• Hand-typed Survey Point from an earlier project phase

In all four cases the SP is correct — you do not want to overwrite it — but GeoBridge does not yet know the UTM convention behind it. The first GeoBridge file import therefore falls back to heuristics: it reads the convention from the SP-X magnitude (>999,999 m ⇒ "with prefix", otherwise "without prefix") and inherits it. For pure UTM projects this is mathematically sound, but it remains a guess — not a documented decision.

Recommendation: before the first import, click the DOP ribbon's "Set SP" button. GeoBridge detects the externally set SP and runs the adopt path (see Basics → Setting the Survey Point manually first): a prefix dialog asks for the convention once, the answer is persisted as a synthetic import record. The Survey Point is left untouched. From this point on, follow-up imports see a documented convention and skip the heuristic.

After the adopt, the Event-Manager button "Toggle UTM prefix…" also becomes useful — particularly for utility-company workflows where the masterfile SP is prefix-encoded (32663250) but the modelling should run in standard UTM without prefix (663250). A single flip shifts the Survey Point by ±N million metres and switches the whole project convention.

Real-world round-trip (user-validated 2026-05-15):

1. Open the project — SP came from a DWG link with 32 663 250 / 5 651 500 (UTM-32 with prefix).
2. Click Set SP → adopt path → prefix dialog → confirm "with prefix zone 32" → synthetic record written.
3. Import 4× DOP, 4× DGM, CityGML — all inherit zone 32, with prefix.
4. Event Manager → Toggle UTM prefix… → "with prefix" flips to "without prefix zone 32" → confirm the before/after dialog → SP jumps to 663 250 / 5 651 500, all geometry stays visually in place.
5. Further imports now run in the "without prefix" convention.