[Bf-extensions-cvs] [e75551f] master: Fix T44536: Add (limited!) normal import for STL.
Bastien Montagne
noreply at git.blender.org
Sun May 3 12:01:08 CEST 2015
Commit: e75551f7062c6ef3d2eee456492a7c6d6bc6aeb2
Author: Bastien Montagne
Date: Sun May 3 11:58:53 2015 +0200
Branches: master
https://developer.blender.org/rBAe75551f7062c6ef3d2eee456492a7c6d6bc6aeb2
Fix T44536: Add (limited!) normal import for STL.
Limited, because STL only stores face normals, so we can only fake this by setting
all clnors of a same face to that face normal... Guess use case are rather limited,
but does not hurt to have it either.
===================================================================
M io_mesh_stl/__init__.py
M io_mesh_stl/blender_utils.py
M io_mesh_stl/stl_utils.py
===================================================================
diff --git a/io_mesh_stl/__init__.py b/io_mesh_stl/__init__.py
index 2094ef5..b08b3f7 100644
--- a/io_mesh_stl/__init__.py
+++ b/io_mesh_stl/__init__.py
@@ -112,6 +112,12 @@ class ImportSTL(Operator, ImportHelper, IOSTLOrientationHelper):
default=True,
)
+ use_facet_normal = BoolProperty(
+ name="Facet Normals",
+ description="Use (import) facet normals (note that this will still give flat shading)",
+ default=False,
+ )
+
def execute(self, context):
from . import stl_utils
from . import blender_utils
@@ -142,8 +148,9 @@ class ImportSTL(Operator, ImportHelper, IOSTLOrientationHelper):
for path in paths:
objName = bpy.path.display_name(os.path.basename(path))
- tris, pts = stl_utils.read_stl(path)
- blender_utils.create_and_link_mesh(objName, tris, pts, global_matrix)
+ tris, tri_nors, pts = stl_utils.read_stl(path)
+ tri_nors = tri_nors if self.use_facet_normal else None
+ blender_utils.create_and_link_mesh(objName, tris, tri_nors, pts, global_matrix)
return {'FINISHED'}
diff --git a/io_mesh_stl/blender_utils.py b/io_mesh_stl/blender_utils.py
index ff507b3..a5492d0 100644
--- a/io_mesh_stl/blender_utils.py
+++ b/io_mesh_stl/blender_utils.py
@@ -19,9 +19,11 @@
# <pep8 compliant>
import bpy
+import array
+from itertools import chain
-def create_and_link_mesh(name, faces, points, global_matrix):
+def create_and_link_mesh(name, faces, face_nors, points, global_matrix):
"""
Create a blender mesh and object called name from a list of
*points* and *faces* and link it in the current scene.
@@ -29,10 +31,30 @@ def create_and_link_mesh(name, faces, points, global_matrix):
mesh = bpy.data.meshes.new(name)
mesh.from_pydata(points, [], faces)
+
+ if face_nors:
+ # Note: we store 'temp' normals in loops, since validate() may alter final mesh,
+ # we can only set custom lnors *after* calling it.
+ mesh.create_normals_split()
+ lnors = tuple(chain(*chain(*zip(face_nors, face_nors, face_nors))))
+ mesh.loops.foreach_set("normal", lnors)
+
mesh.transform(global_matrix)
# update mesh to allow proper display
- mesh.validate()
+ mesh.validate(clean_customdata=False) # *Very* important to not remove lnors here!
+
+ if face_nors:
+ clnors = array.array('f', [0.0] * (len(mesh.loops) * 3))
+ mesh.loops.foreach_get("normal", clnors)
+
+ mesh.polygons.foreach_set("use_smooth", [True] * len(mesh.polygons))
+
+ mesh.normals_split_custom_set(tuple(zip(*(iter(clnors),) * 3)))
+ mesh.use_auto_smooth = True
+ mesh.show_edge_sharp = True
+ mesh.free_normals_split()
+
mesh.update()
scene = bpy.context.scene
diff --git a/io_mesh_stl/stl_utils.py b/io_mesh_stl/stl_utils.py
index 0ab24e3..6294184 100644
--- a/io_mesh_stl/stl_utils.py
+++ b/io_mesh_stl/stl_utils.py
@@ -62,6 +62,15 @@ class ListDict(dict):
return value
+
+# an stl binary file is
+# - 80 bytes of description
+# - 4 bytes of size (unsigned int)
+# - size triangles :
+#
+# - 12 bytes of normal
+# - 9 * 4 bytes of coordinate (3*3 floats)
+# - 2 bytes of garbage (usually 0)
BINARY_HEADER = 80
BINARY_STRIDE = 12 * 4 + 2
@@ -96,19 +105,6 @@ def _is_ascii_file(data):
def _binary_read(data):
- # an stl binary file is
- # - 80 bytes of description
- # - 4 bytes of size (unsigned int)
- # - size triangles :
- #
- # - 12 bytes of normal
- # - 9 * 4 bytes of coordinate (3*3 floats)
- # - 2 bytes of garbage (usually 0)
-
- # OFFSET is to skip normal bytes
- # STRIDE between each triangle (first normal + coordinates + garbage)
- OFFSET = 12
-
# Skip header...
data.seek(BINARY_HEADER)
size = struct.unpack('<I', data.read(4))[0]
@@ -129,15 +125,15 @@ def _binary_read(data):
chunks = [CHUNK_LEN] * (size // CHUNK_LEN)
chunks.append(size % CHUNK_LEN)
- unpack = struct.Struct('<9f').unpack_from
+ unpack = struct.Struct('<12f').unpack_from
for chunk_len in chunks:
if chunk_len == 0:
continue
buf = data.read(BINARY_STRIDE * chunk_len)
for i in range(chunk_len):
- # read the points coordinates of each triangle
- pt = unpack(buf, OFFSET + BINARY_STRIDE * i)
- yield pt[:3], pt[3:6], pt[6:]
+ # read the normal and points coordinates of each triangle
+ pt = unpack(buf, BINARY_STRIDE * i)
+ yield pt[:3], (pt[3:6], pt[6:9], pt[9:])
def _ascii_read(data):
@@ -156,11 +152,15 @@ def _ascii_read(data):
# strip header
data.readline()
+ curr_nor = None
+
for l in data:
- # if we encounter a vertex, read next 2
l = l.lstrip()
+ if l.startswith(b'facet'):
+ curr_nor = tuple(map(float, l_item.split()[2:]))
+ # if we encounter a vertex, read next 2
if l.startswith(b'vertex'):
- yield [tuple(map(float, l_item.split()[1:])) for l_item in (l, data.readline(), data.readline())]
+ yield curr_nor, [tuple(map(float, l_item.split()[1:])) for l_item in (l, data.readline(), data.readline())]
def _binary_write(filepath, faces):
@@ -232,19 +232,22 @@ def read_stl(filepath):
Please note that this process can take lot of time if the file is
huge (~1m30 for a 1 Go stl file on an quad core i7).
- - returns a tuple(triangles, points).
+ - returns a tuple(triangles, triangles' normals, points).
triangles
A list of triangles, each triangle as a tuple of 3 index of
point in *points*.
+ triangles' normals
+ A list of vectors3 (tuples, xyz).
+
points
An indexed list of points, each point is a tuple of 3 float
(xyz).
Example of use:
- >>> tris, pts = read_stl(filepath, lambda x:)
+ >>> tris, tri_nors, pts = read_stl(filepath)
>>> pts = list(pts)
>>>
>>> # print the coordinate of the triangle n
@@ -253,22 +256,23 @@ def read_stl(filepath):
import time
start_time = time.process_time()
- tris, pts = [], ListDict()
+ tris, tri_nors, pts = [], [], ListDict()
with open(filepath, 'rb') as data:
# check for ascii or binary
gen = _ascii_read if _is_ascii_file(data) else _binary_read
- for pt in gen(data):
+ for nor, pt in gen(data):
# Add the triangle and the point.
# If the point is allready in the list of points, the
# index returned by pts.add() will be the one from the
# first equal point inserted.
tris.append([pts.add(p) for p in pt])
+ tri_nors.append(nor)
print('Import finished in %.4f sec.' % (time.process_time() - start_time))
- return tris, pts.list
+ return tris, tri_nors, pts.list
if __name__ == '__main__':
More information about the Bf-extensions-cvs
mailing list