FBX Exporter - Apply Transform

Hi there,

Apologies if this topic has been discussed before. I was wondering if there’s any chance the FBX export addon might be expanded so the ‘Apply Transform’ option could better handle hierarchies of parented objects?

Exporting models with Blender has always been a tricky area when exporting using FBX for use within game engines. Over the last few years the experimental ‘Apply Transform’ has been a step in the direction we need. We have been able to get the result we need for our FBX exports by using ‘Apply Transform’ whch allows our FBX models to import cleanly with a forward Z+ and rotation values (for the root parent object) at 0,0,0, which is great! However when using ‘Apply Transform’ it indiscimintly bakes the transform in for all child objects, but doesn’t retain their transforms relative to their parent objects.

For example, say we have a vehicle model with a body and then four separate wheel objects that are parented to the body. Once exported when using ‘Apply Transform’ their transform values relative to the parent are not respected and are baked in as though the model was a flat hierarchy.

We are able to find some awkward manual work arounds from exporting objects independently, or never parenting objects in Blender and then later reconstructing the heirarchy in a game engine, but it would be amazing if FBX exporting in Blender was able to bake the transform for all objects in a hierarchy while respecting their relative transform to each parent object. This works when ‘Apply Transform’ is not enabled, however when ‘Apply Transform’ is off then we don’t get a clean rotation of 0,0,0.

I’ve had a look at trying to modify the io fbx export script myself looking into how ‘bake_space_transform’ influences the export but was unable to follow along with the code well enough to make any meaningful changes, thanks for reading.