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Help me rotation new object by normal a face other object. I have code that works half. The axes at the selected polygon and the new object must be the same
code - http://pasteall.org/632513/python
scene - http://pasteall.org/blend/index.php?id=48131
Align to vector using Vector.rotation_difference(v)
Altered the script from this answer to find the quaternion rotation difference between the local z axis of the edit mesh and the normal of its selected (active) face.
Run script with target object in edit mode, one face selected and active. An object in scene named "Cube.001" will be located at face centre and oriented by face normal.
import bpy
from mathutils import Matrix, Vector
import bmesh
context = bpy.context
obj = context.edit_object
mw = obj.matrix_world.copy()
bm = bmesh.from_edit_mesh(obj.data)
# for this example jmake a face active
face = bm.select_history.active
o = face.calc_center_median()
# calculate the axis dif in local coords
axis_src = face.normal
# local z-axis
axis_dst = Vector((0, 0, 1))
matrix_rotate = mw.to_3x3()
matrix_rotate = matrix_rotate * axis_src.rotation_difference(axis_dst).to_matrix()
matrix_translation = Matrix.Translation(mw * o) #
obj2 = context.scene.objects.get("Cube.001")
obj2.matrix_world = matrix_translation * matrix_rotate.to_4x4()
Result of script. Moved cube in edit mode, showing local coords.
Matrix(norm, tangent, norm.cross(tangent)). Apologies.
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Oct 28, 2017 at 0:07
Alexander Nedovizin solved this problem
import bpy
from mathutils import Matrix, Vector
import bmesh
context = bpy.context
obj = context.edit_object
mw = obj.matrix_world.copy()
bm = bmesh.from_edit_mesh(obj.data)
face = bm.select_history.active
o = face.calc_center_median()
axis_src = face.normal
axis_src2 = face.calc_tangent_edge()
axis_dst = Vector((0, 0, 1))
axis_dst2 = Vector((0, 1, 0))
vec2 = axis_src * obj.matrix_world.inverted()
matrix_rotate = axis_dst.rotation_difference(vec2).to_matrix().to_4x4()
vec1 = axis_src2 * obj.matrix_world.inverted()
axis_dst2 = axis_dst2*matrix_rotate.inverted()
mat_tmp = axis_dst2.rotation_difference(vec1).to_matrix().to_4x4()
matrix_rotate = mat_tmp*matrix_rotate
matrix_translation = Matrix.Translation(mw * o) #
obj2 = context.scene.objects.get("Cube.001")
obj2.matrix_world = matrix_translation * matrix_rotate.to_4x4()
I had to modify Alexander's solution a bit to make it work:
import bpy
import mathutils
C = bpy.context
cursor = C.scene.cursor
obj = C.active_object
p = obj.data.polygons
#get the normal and center of the selected face
normal = obj.data.polygons[p.active].normal
center = obj.data.polygons[p.active].center
#generate a quaternion rotation from the normal vector
up = normal.to_track_quat('X', 'Y')
print(up)
#set the cursor to the center location and rotate it to match the up vector
cursor.location = center
cursor.rotation_quaternion = up
cursor.rotation_quaternion.to_euler()
#get the object world matrix
mat = obj.matrix_world
print(mat)
#generate the location and rotation
rot = cursor.rotation_quaternion.to_euler()
print(rot)
loc = mat @ cursor.location.copy()
obj2 = C.scene.objects.get("Cube.001")
obj2.location = loc
obj2.rotation_euler = rot
#bpy.ops.object.mode_set(mode='OBJECT')
#bpy.ops.mesh.primitive_cube_add(location = loc, size = 0.1, rotation =rot)
#bpy.ops.object.empty_add(type='ARROWS',location = loc, rotation =rot)
