Conversion map

Last updated 05-11-2026

What MC Bridge accepts, what it builds for each machine family, and which conversions work today. Keep a copy of your originals — packs are deleted after a day.

1. Inputs accepted

Kind	Formats	Notes
Surface / design	LandXML (`.xml` / `.landxml`), DXF, DWG, TRM, TTM, Trimble `.dsz` / loose `.svd`, Topcon `.tp3` / `.tn3`	DXF with 3D faces = surface. DXF with only 3D lines = linework-only (convert lines, or triangulate). Civil 3D proxy DWG is refused — send LandXML or extracted 3D polylines. Plain DWG usually needs a DXF twin. TTM is read then staged as temporary LandXML for other brands. A `.dsz` carries SVD surface ± SVL linework inside. Loose `.svd` / `.tn3` / `.tp3` are converted to LandXML (and linework where present) before the build.
Linework	DXF, Trimble loose `.svl`, Topcon `.ln3` (and linework inside a `.dsz` / `.tp3`)	Loose `.svl` / `.ln3` become DXF for the build. Topcon TN3/LN3 readers match the MC Bridge writer layout — exotic office files may not read.
Project zip	`.zip` of a project folder or project library	Unpacked on upload; surface, linework and calibration inside are picked for you (including loose SVD/SVL and Topcon TP3/TN3/LN3 when present).
Calibration / Local	`.cal`, `.dc`, `.gc3`, `.lok` (+ optional control `.csv` with a `.lok`)	Needed when you choose Local / site calibration. Control CSV columns: name, lat, lon, h, N, E, H. A TP3 that already carries localisation can supply a GC3.

2. Outputs by machine family

Machine	What you get	Local calibration
Leica	Project-style pack. Surface as LandXML/DXF, or the TRM shipped as-is when the source is already TRM. Surfaces over about 10 MB are auto-switched to TRM (DXF linework kept).	`.lok` shipped as-is
Trimble Earthworks	`.dsz` (or SVD + SVL pack). If the input was a `.dsz`, it is shipped as supplied.	`.cal`
Trimble GCS900	SVD + optional SVL (+ cal)	`.cal`
Topcon	Default: one self-contained TP3 (surface + linework + GC3 or OS National Grid). Optional: Split into TN3 + LN3 + GC3 (checkbox when Topcon is selected) — surface→TN3, linework→LN3, localisation→GC3 when Local (as today). Linework-only → LN3(s); surface-only → TN3 (+ GC3 if Local).	GC3 (from `.cal` / `.dc` / `.lok` conversion, or from a TP3 that already carried it)

3. What converts to what

From	To	Works?
Design (LandXML, DXF surface/lines, TRM, TTM, `.dsz`, loose `.svd`/`.svl`, Topcon `.tp3`/`.tn3`/`.ln3`)	Any of the four machine families	Yes — when a surface is present, or you choose the linework-only path
Brand A machine file (`.dsz`, TRM, TTM, SVD/SVL, Topcon TP3/TN3/LN3)	Brand B pack	Yes for those inputs (Topcon binary inputs use the MC Bridge writer layout)
Linework-only DXF / SVL / LN3	Lines only, or triangulated surface	Yes — you choose at analyse
Corridor / road alignment	Machine road files	No writers yet — surface + 3D strings only

4. Limits and layout notes

Topcon .tn3 / .ln3 as inputs are read when they match the MC Bridge writer layout. Files from other office tools may not parse.
A Topcon .tp3 is unpacked to surface ± linework ± localisation; linework recovery is best-effort when the polyline layout matches.

5. Coordinate systems

Default shortlist for UK / Ireland: OS National Grid (OSTN15 / OSGM15), legacy OSTN02, HS2 Survey Grid, ITM (Malin Head), TM75 Irish Grid, plus Local.
Local via calibration files (.cal / .dc / .gc3 / .lok).
ITM for Northern Ireland is not enabled on this build.

6. Notes

Prefer a DXF twin over a lone DWG.
Check levels, CRS and calibration on site before working to a pack.
Support for any format can change if a manufacturer changes it.

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