February 8, 2017

FBX Files – Meshes with Images for Real-World Context

Aldred Boyd | Application Engineer - Technical

I recently had an interesting query: how can FBX files generated through aerial photography be useful to clients of Micrographics? The FBX files consist of a mesh of rather a large size, and so I was confident it would put the different software to test. On average they were between 10 and 15 MB in size. I was given three that interlock like tiles in the larger scheme of things.

The best results were achieved using Infraworks. It was a simple matter to input:

Coordinate System WSG 84 Lo 19
Coordinate Origen
Map Y to Z

The Results were outstanding, as can be seen below:

Multiple FBX tiles are used if large areas are of interest.

The individual photographs have resolution of approximately 60mm, with an overall absolute accuracy of around 200mm. The Infraworks images shown below the FBX import shows road objects inferred from GIS data, and thus there is also some question as to their absolute accuracy. Even so, for general design purposes, the two formats correlate very well. Were it the case that even more accuracy would be required, I would invest in generating point cloud of sub millimetric accuracy using high density laser scans.

Clearly a lot more detail is contained in the FBX file than natively in Navisworks.

Creating a storyboard in Infraworks allows one to produce a video.

I was unable to import this FBX into either AutoCAD or AutoCAD Civil 3D, but did manage to open a .DWG file that was generated instead of the FBX. The mesh did not import as one element though, as can be seen by the different colours I applied to the mesh objects. The DWG had no texture (picture).

Using an Add-In I also managed to import an .OBJ file that was generated instead of the FBX. The OBJ texture could only be displayed in AutoCAD.

It failed to display in AutoCAD Civil 3D.

Better results were obtained in Navisworks.

I also imported the FBX file into Lumion and achieved great results.

In Conclusion:

FBX files were great to give context around an existing architectural design, especially in
- Infraworks
- Lumion
Infraworks has the added advantage that high density laser scans may be incorporated in close proximity to the building of interest (Lumion does not host point clouds)
FBX and OBJ files were not as friendly to use in AutoCAD, AutoCAD Civil 3D or Revit.
- In these platforms it may be better to use point clouds to reference designs to or to develop them from.

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About the Author

Aldred Boyd | Application Engineer - Technical

Aldred is an Application Engineer with over 22 years of experience working with Autodesk products. His primary focus is in a consultative role for the manufacturing industry, where he identifies potential challenges within a company's workflow and processes. His extensive experience enables him to identify these challenges and resolve them through the addition of software, training, or further development to address the issues encountered.