OBJ_TO_PLY is a C program which converts an Alias OBJ file to a PLY file, by Greg Turk.
obj_to_ply [flags] < file.obj > file.plywhere
OBJ_TO_PLY is available in a C version.
IVCON, a C++ program which can convert between the Alias OBJ format and other formats.
IVREAD, a FORTRAN90 program which can convert between the Alias OBJ and other formats.
OBJ, a data directory which contains some information about the Alias OBJ format.
OBJ_IO, a FORTRAN90 library which transfers graphics information to and from Alias OBJ files.
OBJ2OPENGL, a PERL script which converts an OBJ file to a C/C++ include file appropriate for use with OpenGL
PLATO_PLY, a C program which creates a Platonic solid and writes it to an ASCII PLY file.
PLY, a data directory which contains some information about the PLY format.
PLY_TO_IV, a C program which can convert a PLY file to the IV format.
PLY_IO, a C library which has some routines needed by OBJ_TO_PLY.
PLY_IO, a MATLAB library which reads or writes a PLY file.
PLY_TO_OBJ, a C program which reads a PLY 3D graphics file and writes an equivalent OBJ graphics file.
TEC_TO_OBJ, a FORTRAN90 program which can read a TECPLOT file describing a surface in 3D composed of triangles or quadrilaterals, and write an OBJ file.
You can go up one level to the C source codes.