libigl file formats
- .bf ASCII files for representing skeletal bone "forests"
- .dmat uncompressed ASCII/binary files for dense matrices
- .ele Element (triangle or tet) list. This format comes in similar flavors: tetgen's, stellar's,
The formats of TetGen and stellar are identical upto conventions on index
ordering and number of allowed attributes (unverified).
- .face TetGen's file format for simplicial facets.
- .mesh Medit's triangle surface mesh + tetrahedral volume mesh file format, see page 33, section 7.2.1
- .node List of points (vertices). Described indentically (upto
accepted dimensions, use of attributes and boundary markers) by Triangle, TetGen, and Stellar.
- .off Geomview's polyhedral file format
- .obj Wavefront object file format. Usually unsafe to assume anything more than vertex positions and triangle indices are supported
Portable Network Graphics image file. IGLLIB (in the libiglpng extra)
supports png image files via the yimg
library. Alpha channels and compression are suppported.
- .poly Piecewise-linear complex. This format comes in many similar but importantly different flavors:
triangle's, tetgen's, pyramid/SVR's
- .rbr ASCII files for saving state of ReAntTweakBar
- .tga Truevision TGA or TARGA image file format. IGLLIB supports only very basic reading and writing RGB/RGBA files without colormaps and (unverified) run-length compression.
- .tgf ASCII files for representing control handle graphs
VRML (Virtual Reality Modeling Language) file format for 3D scenes.
- .xml XMLSerializer's file format containing the serialization of object data structures.
Triangle mesh file format performance
and .off file
formats support meshes with arbitrary polygon degrees. However, often we are
only working with triangle meshes. Further, .obj files do not have useful
headers revealing the number of elements. For triangle meshes, .off and .obj
are inferior file formats to the .mesh
file format. The current (version 0.1.6) IO functions for these file formats perform as follows for reading and writing a 300,000 triangle mesh:
writeOBJ: 1.33742 secs
writeOFF: 0.510111 secs
writeMESH: 0.218139 secs
readOBJ: 1.3782 secs
readOFF: 0.691496 secs
readMESH: 0.242315 secs
This reveals that .mesh is 6.5x faster than .obj and about 2.5x faster than .off.
While .obj files support normals, it is typically much faster to (re)compute
normals from the geometry using
per_corner_normals than to read
and write them to files.
It gets even better if you're willing to use a nonstandard format. If your
triangle mesh is in (
F) then you can read and
write those variables as dense matrices of doubles to
.dmat uncompressed binary files.
This not only ensures perfect precision but also big speed ups. On that same
300,000 triangle mesh, .dmat achieves:
writeDMAT: 0.0384338 secs
readDMAT: 0.0117921 secs
This reveals that binary .dmat files are 34x/116x faster at writing and
reading than .obj and a hefty 5x/20x over .mesh. In this case it may pay to
compute normals once into
N and also read and write it to a