VU.CITY supports models in FBX format (2011 or newer) and also supports OBJ files.

If your chosen CAD/BIM software cannot export to FBX, you can convert DXF, DAE, and 3DS files using this FBX converter from Autodesk.

Converting different CAD/BIM formats to FBX/OBJ can produce mixed results, so please review the following to understand what constitutes a good FBX/OBJ file.

Meshes and faces

VU.CITY supports meshes only. NURBS, curves, or surfaces must be converted into mesh to be rendered.

Faces within these meshes should either be triangles or quadrilaterals, as n-gons are not supported.

Models with multiple meshes can't be selected by the ZTV, object highlighter or camera tool. We suggest merging models into a single mesh/node for full compatibility.

Materials and textures

Models can include standard Autodesk materials; Revit and other app-specific materials are not supported. While VU.CITY can import UV-mapped models, this feature is best utilised witha software capable of integrating UV maps into materials, such as the latest version of 3ds Max.

File Size

While there is no theoretical file size limit, we recommend keeping files well below 128MB for performance reasons.

It is not necessary to join/collapse/merge/explode your geometry, though doing so can greatly improve rendering performance and reduce your file size. To further help keep your file size down, we recommend exporting only the externally visible geometry (i.e. not exporting interiors / furniture etc), and leaving out terrain / surrounding buildings (VU.CITY already contains both).

Geolocation

For the UK, geolocation should conform to the British National Grid (GBOS).

For Ireland, geolocation should conform to Irish Transverse Mercator (ITM).

All other supported locations use UTM projection.

Geolocating and georeferencing are not the same thing, and it's important for architects and BIM managers to understand the difference to get the best out of VU.CITY. Please see here to learn about the difference, and how to position/orient your model in a way that works for rendering formats like FBX and OBJ.

Elevation / AOD

A good practice is to extrude your model downwards so that the base of it sits at sea level (i.e. AOD 0). This helps prevent visible gaps between the building base and the VU.CITY terrain, particularly when the model is placed on a slope or hill, ensuring it does not appear to float above the terrain. This approach is especially useful in schemes involving landscaping. However, it may affect ZTV results. The part of the model below ground level is assigned a red band, which is not visible in the analysis. As a result, the ZTV output may appear to lack red tones corresponding to those hidden areas.