Ability to export with custom split normals

[Growl3D]

The problem

Currently the exporter doesn't support custom split normals. These are used when the bevel modifier has the "Harden Normals" setting checked, or when using the Weighted Normal modifier. The autosmooth setting, found in the object data properties, under the subheading, normals, is required for these settings to work correctly. This causes faces to maintain uniform and flat shading on the model, while maintaining smooth curvature, unlike the usual method of using the edge split modifier.

The current workflow

Currently I am turning off the specularity in the material settings, using the edge split method instead to avoid any odd shading, and making use of 'container loops'.

The solution

For support to be added for this feature if at all possible, I can provide a test file if necessary.