first pass on proper reference distance units in 2.8+

fspy_blender/addon.py

@@ -194,6 +194,58 @@ def set_up_3d_area(self, project, camera, update_existing_camera, set_background
 
             break # only set up one 3D area
 
+    def set_reference_distance_unit(self, project, camera):
+        scene = bpy.context.scene
+        unit_settings = scene.unit_settings
+        if not hasattr(unit_settings, 'length_unit'):
+            return
+
+        unit = project.reference_distance_unit
+        is_imperial = False
+        blender_unit = None
+        scale_length = None
+        if unit == 'Millimeters':
+            blender_unit = 'MILLIMETERS'
+            scale_length = 0.001
+        elif unit == 'Centimeters':
+            blender_unit = 'CENTIMETERS'
+            scale_length = 0.01
+        elif unit == 'Meters':
+            blender_unit = 'METERS'
+            scale_length = 1.0
+            blender_unit = 'METERS'
+        elif unit == 'Kilometers':
+            blender_unit = 'KILOMETERS'
+            scale_length = 1000.0
+            blender_unit = 'KILOMETERS'
+        elif unit == 'Inches':
+            blender_unit = 'INCHES'
+            scale_length = 1.0 / 12.0
+            is_imperial = True
+        elif unit == 'Feet':
+            blender_unit = 'FEET'
+            scale_length = 1.0
+            is_imperial = True
+        elif unit == 'Miles':
+            blender_unit = 'MILES'
+            scale_length = 5280.0
+            is_imperial = True
+
+        if blender_unit:
+            distance_scale = 1.0
+            if is_imperial:
+                distance_scale = 1.0 / 3.2808399
+                unit_settings.system = 'IMPERIAL'
+            else:
+                unit_settings.system = 'METRIC'
+            unit_settings.length_unit = blender_unit
+            unit_settings.scale_length = scale_length
+            camera.location.x *= distance_scale
+            camera.location.y *= distance_scale
+            camera.location.z *= distance_scale
+        else:
+            unit_settings.system = 'NONE'
+            unit_settings.scale_length = 1.0
 
     def import_fpsy_project(self, context, filepath, update_existing_camera, set_background_image):
         try:
@@ -205,6 +257,7 @@ def import_fpsy_project(self, context, filepath, update_existing_camera, set_bac
                 return { 'CANCELLED' }
             self.set_render_resolution(project)
             self.set_up_3d_area(project, camera, update_existing_camera, set_background_image)
+            self.set_reference_distance_unit(project, camera)
             self.report({ 'INFO' }, "Finished setting up camera '" + project.file_name + "'")
             return {'FINISHED'}
         except fspy.ParsingError as e:

fspy_blender/fspy.py

@@ -52,6 +52,7 @@ def __init__(self, project_path):
     project_file.seek(16)
     state = json.loads(project_file.read(state_string_size).decode('utf-8'))
     self.camera_parameters = CameraParameters(state["cameraParameters"])
-
+    calibration_settings = state["calibrationSettingsBase"]
+    self.reference_distance_unit = calibration_settings["referenceDistanceUnit"]
     self.image_data = project_file.read(image_buffer_size)
     self.file_name = os.path.basename(project_path)