Navisworks DWF export - Inaccurate geometry large coordinates

[Plorenzo]

When exporting a DWF from Navisworks (2013/2014), where the coordinates are in GPS/World/Survey coordinates (very large numbers), the geometry becomes very innacurate. See attached picture. 

This happens, regardless of any transform overrides within Navisworks 2013/2014. I understand this must be a floating point rounding issue that has to do with very large coordinate values. 

This is a big problem, especially with anyone working with DWF files. Can the Navisworks team fix this problem?

[tim.wiegand]

DWF is a single precision floating point format. It is only suitable for models that are close to the origin.

The Navisworks DWF export tries to preserve the selection tree and transform structure when exporting. Unfortunately, this means that if the original model contains transforms with large coordinates that will be loss of accuracy in the DWF.

To fix this in the Navisworks export the user would need to apply an override to put the model close to the origin and the export code would need to collapse the model structure to avoid any internal large transforms.

[Plorenzo]

Yes, I tried to apply an override within Navisworks to bring the model close to the origin, however the same floating point innacuracy occurs as if the override was never done.

Please correct me if I'm wrong, but I suspect that during the DWF export, the geometry is exported according to the original coordinates first (thus creating floating point rounding innacuracy), then applies the transform override. I have tried this with a wide variety of models. 

[tim.wiegand]

Yes, that's pretty much what is happening. To fix this on the Navisworks side the export code will need to collapse everything down so that coordinates and transforms are all close to the origin. That will mean losing some or all of the object and property information in the DWF.

This is not a quick fix. At a minimum would need to add an option to control whether the structure should be collapsed. The simplest implementation would be an option that would remove the object/property structure entirely and just include the graphics data in the DWF. Would this work for your use case?

[Plorenzo]

That would work... the only issue would be that layers would no longer be available, but it's a suitable and essential workaround for now, and it would be very much appreciated!

[tim.wiegand]

I've logged a bug for this issue and it will be considered for a future release.