vector manip

snippets/bpy/get_view_vector.py

@@ -0,0 +1,65 @@
+## Get viewport's current view vector or camera view vector
+
+import bpy
+from mathutils import Vector
+
+# Standalone functions
+
+def get_viewport_view_vector():
+    '''return current viewport view vector (normalized direction)'''
+    view_vector = Vector((0,0,-1))
+    view_vector.rotate(bpy.context.space_data.region_3d.view_rotation)
+    return view_vector
+
+def get_camera_view_vector():
+    '''return active camera view vector (normalized direction)
+    return None if no active camera
+    '''
+    view_vector = Vector((0,0,-1))
+    if not bpy.context.scene.camera:
+        return
+    view_vector.rotate(bpy.context.scene.camera.matrix_world)
+    return view_vector
+
+
+# Mixed function (with camera as option)
+
+def get_view_vector(camera=False):
+    '''return current viewport view vector (normalized direction)
+    camera: if True return active camera view vector (None if no active camera)
+    '''
+    view_vector = Vector((0,0,-1))
+    if camera:
+        if not bpy.context.scene.camera:
+            return
+        view_vector.rotate(bpy.context.scene.camera.matrix_world)
+
+    else:
+        view_vector.rotate(bpy.context.space_data.region_3d.view_rotation)
+
+    return view_vector
+
+## ----
+
+## For camera
+cam_view_vec = get_camera_view_vector()
+
+
+## For view vector
+## In view 3D context
+# view_vec = get_view_vector()
+# view_vec = get_viewport_view_vector()
+
+## Here with context override for use from text editor
+def get_viewport_override():
+    for window in bpy.context.window_manager.windows:
+        screen = window.screen
+        for area in screen.areas:
+            if area.type == 'VIEW_3D':
+                return {'window': window, 'screen': screen, 'area': area}
+
+with bpy.context.temp_override(**get_viewport_override()):
+    view_vec = get_view_vector()
+
+print("camera view vector:", cam_view_vec)
+print("view vector:", view_vec)

snippets/math/rotate_object_on_axis.py

@@ -0,0 +1,37 @@
+## Rotate object by some angle on defined axis
+## if angle value is in degree, use: math.radians(angle)
+
+import bpy
+from math import pi, radians
+from mathutils import Matrix, Vector
+
+def rotate_on_axis(obj, axis, angle):
+    '''Rotate passed object on axis by an angle
+    obj: Object to rotate
+    axis: an axis as string, ex: "X", or a Vector, ex: Vector((0,0,1))
+    angle: An angle value in radians (signed)
+    ''' 
+
+    ## Create rotation matrix
+    rot_matrix = Matrix.Rotation(angle, 4, axis)
+    ## create a working copy of current matrix
+    mat = obj.matrix_world.copy()
+
+    ## Reset translation, rotate, re-apply translation
+    mat.translation = Vector((0,0,0))
+    mat = rot_matrix @ mat
+    mat.translation = obj.matrix_world.translation
+
+    # Assign new rotated matrix
+    obj.matrix_world = mat
+
+
+## Rotate active object by 90 degrees (in radians: pi/2)...
+
+## ... on global Z axis
+rotate_on_axis(bpy.context.object, "Z", pi/2)
+
+## ... on current view axis (need to be executed in viewport context, using a context override from script editor)
+# view_vector = Vector((0,0,-1))
+# view_vector.rotate(bpy.context.space_data.region_3d.view_rotation)
+# rotate_on_axis(bpy.context.object, view_vector, pi/2)