Hello,
I'm new to the list and relatively new to Maya.
I've been missing a tool in Cinema 4D that allows the user to select
contiguous faces within boundaries defined by differences in polygon normal
angles (boundaries = hard edges or an arbitrary angle), so I rolled my own
Maya script.
It seems to be working well, but it gets quite slow as the number of faces
to select increases. For example, on my home PC it takes about 6 seconds
to select 320 faces along the inside of a ring.
If you have any ideas on how I could implement this more efficiently I
would love your input. I've heard that PyMEL tends to be the slowest of
options for scripting, but it's super convenient to work in a more
'pythonic' mode. I started playing with the OpenMaya API but found that it
doesn't seem to have a polyListComponentConversion equivalent and my brain
is fried enough that I can't think about implementing my own version using
the API. I have a suspicion that the polyListComponentConversion function
is one of those adding the most time to execution; I'm using it to find
the boundary edges of the faces currently marked for selection.
I've attached a .py file and pasted my code here as well:
import pymel.core as pm
import time
import itertools
def compare_normals(n1, n2):
#Take dot product of normals and convert to degrees difference
return 90.0 * (1.0 - n1*n2)
def check_angle(edge, angle, hard_edges=True):
if edge.isOnBoundary():
#Boundary reached; no need to continue!
return False
soft = True
if hard_edges:
#Check for hard or soft edge
soft = edge.isSmooth()
#Get all faces connected to this edge
faces = pm.ls(edge.connectedFaces(), fl=True)
#Compare the face normals between edges to determine if the face should
be selected
face_compare = {c for c in itertools.combinations(faces, 2) if
compare_normals(c[0].getNormal(), c[1].getNormal()) > angle}
#Returns True if the face should be selected
return len(face_compare) == 0 and soft
def get_connected_faces(faces, angle=0.0, hard_edges=True):
#Get edge boundary of current face selection
boundary = pm.ls(pm.polyListComponentConversion(faces, bo=True,
te=True), fl=True)
#Combine currently selected faces with neighboring faces that pass the
face normal test
new_faces = faces | set(pm.ls([edge.connectedFaces() for edge in
boundary if \
check_angle(edge, angle, hard_edges)],
fl=True))
if new_faces != faces:
#Yield the new faces to select for as long as we haven't exhausted
our supply
yield new_faces
#Stop when there are no more faces to select
raise StopIteration
t1 = time.clock()
angle_tolerance = 30.0
hard_edges = True
#Get the initial selection
selection = pm.ls(sl=True, fl=True)
#Filter the selection to face components
selected_faces = {face for face in selection if isinstance(face,
pm.general.MeshFace)}
if selected_faces:
#Since there are faces selected...
try:
while True:
#Find new neighboring faces until no more meet the criteria
selected_faces = get_connected_faces(selected_faces,
angle_tolerance).next()
except StopIteration:
#Select all faces found
pm.select(selected_faces)
t2 = time.clock()
#Report our performance
print("Selected {0} faces in {1:.2f}
seconds.".format(len(selected_faces), t2-t1))
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import pymel.core as pm
import time
import itertools
def compare_normals(n1, n2):
#Take dot product of normals and convert to degrees difference
return 90.0 * (1.0 - n1*n2)
def check_angle(edge, angle, hard_edges=True):
if edge.isOnBoundary():
#Boundary reached; no need to continue!
return False
soft = True
if hard_edges:
#Check for hard or soft edge
soft = edge.isSmooth()
#Get all faces connected to this edge
faces = pm.ls(edge.connectedFaces(), fl=True)
#Compare the face normals between edges to determine if the face should be selected
face_compare = {c for c in itertools.combinations(faces, 2) if compare_normals(c[0].getNormal(), c[1].getNormal()) > angle}
#Returns True if the face should be selected
return len(face_compare) == 0 and soft
def get_connected_faces(faces, angle=0.0, hard_edges=True):
#Get edge boundary of current face selection
boundary = pm.ls(pm.polyListComponentConversion(faces, bo=True, te=True), fl=True)
#Combine currently selected faces with neighboring faces that pass the face normal test
new_faces = faces | set(pm.ls([edge.connectedFaces() for edge in boundary if \
check_angle(edge, angle, hard_edges)], fl=True))
if new_faces != faces:
#Yield the new faces to select for as long as we haven't exhausted our supply
yield new_faces
#Stop when there are no more faces to select
raise StopIteration
t1 = time.clock()
angle_tolerance = 30.0
hard_edges = True
#Get the initial selection
selection = pm.ls(sl=True, fl=True)
#Filter the selection to face components
selected_faces = {face for face in selection if isinstance(face, pm.general.MeshFace)}
if selected_faces:
#Since there are faces selected...
try:
while True:
#Find new neighboring faces until no more meet the criteria
selected_faces = get_connected_faces(selected_faces, angle_tolerance).next()
except StopIteration:
#Select all faces found
pm.select(selected_faces)
t2 = time.clock()
#Report our performance
print("Selected {0} faces in {1:.2f} seconds.".format(len(selected_faces), t2-t1))
