from zmesh import Mesher
labels = ... # some dense volumetric labeled image
mesher = Mesher( (4,4,40) ) # anisotropy of image
# initial marching cubes pass
# close controls whether meshes touching
# the image boundary are left open or closed
mesher.mesh(labels, close=False)
meshes = []
for obj_id in mesher.ids():
meshes.append(
mesher.get_mesh(
obj_id,
normals=False, # whether to calculate normals or not
# tries to reduce triangles by this factor
# 0 disables simplification
simplification_factor=100,
# Max tolerable error in physical distance
max_simplification_error=8,
# whether meshes should be centered in the voxel
# on (0,0,0) [False] or (0.5,0.5,0.5) [True]
voxel_centered=False,
)
)
mesher.erase(obj_id) # delete high res mesh
mesher.clear() # clear memory retained by mesher
mesh = meshes[0]
mesh = mesher.simplify(
mesh,
# same as simplification_factor in get_mesh
reduction_factor=100,
# same as max_simplification_error in get_mesh
max_error=40,
compute_normals=False, # whether to also compute face normals
) # apply simplifier to a pre-existing mesh
# compute normals without simplifying
mesh = mesher.compute_normals(mesh)
mesh.vertices
mesh.faces
mesh.normals
mesh.triangles() # compute triangles from vertices and faces
# Extremely common obj format
with open('iconic_doge.obj', 'wb') as f:
f.write(mesh.to_obj())
# Common binary format
with open('iconic_doge.ply', 'wb') as f:
f.write(mesh.to_ply())
# Neuroglancer Precomputed format
with open('10001001:0', 'wb') as f:
f.write(mesh.to_precomputed())
If binaries are available for your system:
pip install zmesh
Requires a C++ compiler and boost
Note that you may need to set the environment variable BOOST_ROOT
.
sudo apt-get install python3-dev libboost-all-dev
pip install zmesh --no-binary :all:
- The mesher will consume about double memory in 64 bit mode if the size of the object exceeds <1023, 1023, 511> on the x, y, or z axes. This is due to a limitation of the 32-bit format.
- The mesher is ambidextrous, it can handle C or Fortran order arrays.
- The maximum vertex range supported
.simplify
after converting to voxel space is 220 (appx. 1M) due to the packed 64-bit vertex format. - There is a longstanding design flaw in
cMesher.hpp
that transposes the returned mesh and resolution. We're working on a backwards compatible solution. That's why you need to domesher.mesh(data.T)
.
- zi_lib - zmesh makes heavy use of Aleks' C++ library.
- Igneous - Visualization of connectomics data using cloud computing.
Thanks to Aleks Zlateski for creating and sharing this beautiful mesher.
Later changes by Will Silversmith, Nico Kemnitz, and Jingpeng Wu.
- W. Lorensen and H. Cline. "Marching Cubes: A High Resolution 3D Surface Construction Algorithm". pp 163-169. Computer Graphics, Volume 21, Number 4, July 1987. (link)
- M. Garland and P. Heckbert. "Surface simplification using quadric error metrics". SIGGRAPH '97: Proceedings of the 24th annual conference on Computer graphics and interactive techniques. Pages 209–216. August 1997. doi: 10.1145/258734.258849 (link)
- H. Hoppe. "New Quadric Metric for Simplifying Meshes with Appearance Attributes". IEEE Visualization 1999 Conference. pp. 59-66. doi: 10.1109/VISUAL.1999.809869 (link)