glTF importer: set empty display size, based on distance parent/children

io_scene_gltf2/__init__.py

@@ -15,7 +15,7 @@
 bl_info = {
     'name': 'glTF 2.0 format',
     'author': 'Julien Duroure, Scurest, Norbert Nopper, Urs Hanselmann, Moritz Becher, Benjamin Schmithüsen, Jim Eckerlein, and many external contributors',
-    "version": (1, 8, 9),
+    "version": (1, 8, 10),
     'blender': (3, 0, 0),
     'location': 'File > Import-Export',
     'description': 'Import-Export as glTF 2.0',

io_scene_gltf2/blender/imp/gltf2_blender_node.py

@@ -75,8 +75,10 @@ class BlenderNode():
             obj = bpy.data.objects.new(name, armature)
 
         else:
+            # Empty
             name = vnode.name or vnode.default_name
             obj = bpy.data.objects.new(name, None)
+            obj.empty_display_size = BlenderNode.calc_empty_display_size(gltf, vnode_id)
 
         vnode.blender_object = obj
 
@@ -111,6 +113,17 @@ class BlenderNode():
 
         return obj
 
+    @staticmethod
+    def calc_empty_display_size(gltf, vnode_id):
+        # Use min distance to parent/children to guess size
+        sizes = []
+        vids = [vnode_id] + gltf.vnodes[vnode_id].children
+        for vid in vids:
+            vnode = gltf.vnodes[vid]
+            dist = vnode.trs()[0].length
+            sizes.append(dist * 0.4)
+        return max(min(sizes, default=1), 0.001)    
+
     @staticmethod
     def create_bones(gltf, arma_id):
         arma = gltf.vnodes[arma_id]