Exporting tangents and binormals

[Anonymous]

Hi. I am creating some basic objects and trying to export them in fbx format with tangent and binormal data.But tangents are not exported or not being parsed by FBX Importer class, unless i add a UVW map modifier to object right after i created it. I mean if i convert my object to editable poly and then add UVW Modifier to it, no tangent or binormal layer is created for the exported object.But if i create a object,add a UVW Modifier to it and finally convert it to editable poly both tangents and binormals are exported well.Is there such a bug in FBX 2013 SDK or am i missing something. I tried to export scene with also FBX 2012,2011,binary,ascii..But i couldn't make it work.

[Anonymous]

Hello BuraCULa,

You've run into a limitation of the plug-in. The following is from the FBX documentation:

"There is a known FBX limitation where exported binormal and/or tangent information does not appear, even if you activate the Export Include Geometry Tangents and Binormals option.

The Tangents and Binormals option only works on meshes that have only triangle polygons, so you may need to triangulate the mesh before activating this option. "

The geometry has to be triangulated before export (all diagonal edges must be displayed on the mesh before export). If it isn't already, you can make it an editable mesh, or as you saw, leave it as default, as long as it is in triangles. After importing into Max or Maya, you can try and run the Quadify Modifier in Max or use Quadrangulate in Maya to return you geometry to quads.

Regards,
Carlos

[Anonymous]

Sadly this bug appears to persist even with a model that uses exclusively triangles (maya 2012, current Fbx exporter,, fbx_dae format)

No tangents or binormals. Any hints would be greatly appreciated!

(Update: "pure" FBX works -- it's the FBX_DAE that fials (some other issues, too))