average_objects
		---------------

  average_objects output.obj input1.obj [input2.obj [input3.obj ...]]

Reads a number of input files, which may be of any type as long
as each has the same number of points.  Output a file of the type
of input1.obj, but with the point position set to the mean position
of the corresponding points in the input files.


		average_surfaces
		----------------

  average_surfaces output.obj  none|rms_file  none|variance_file n_groups
                   input1.obj [input2.obj...]

Reads a number of surface (POLYGONS) files, and outputs the mean surface,
computed as for average_objects.  In addition, the RMS distance and
inverse covariance matrix can be written to files.


		create_grid
		-----------

  create_grid out.obj x|y|z slice_position [x|y|z line_position] ...

The file out.obj consists of a set of lines in the specified plane
X=slice_position (or Y= or Z=).  The set of lines desired are
specified in the following pairs of arguments.



		dump_curvatures
		---------------

  dump_curvatures  object_file  output_file  [curvature_distance]

The parameter curvature_distance defaults to 4.



		evaluate
		--------

  evaluate  volume.mnc  input.obj  output.txt [degree]

degree is an integer, passed to evaluate_volume_in_world(), where 
-1 = nearest-neighbour, otherwise use an order-(degree+1) 
polynomial to interpolate

Typically used for vertex colouring of objects.  For each vertex of the
geometrical object, the point is located in the volume.  The volume values 
are written to the output text file in the order that the vertices are 
visited.  Each object in the BIC obj file is processed in sequence.



		make_slice
		----------

  make_slice in.mnc out.obj  x|y|z  v|w pos [xt] [yt]

The file in.mnc sets the coordinate systems.  The output
consists of a polygon or quadmesh in the plane "X=pos" 
(Y=pos, Z=pos, respectively), in either the voxel or
world coordinate system depending on the 4th parameter.
The optional parameters "xt" and "yt" specify the number
of rows and columns in the mesh; the values "2 2" are
the most useful.



		set_line_width
		--------------

  set_line_width in.obj out.obj [thickness]

Copies in.obj to out.obj, changing the thickness of any
LINES objects found.  The default thickness is 1.0.



		set_object_colour
		-----------------

  set_object_colour in.obj out.obj colour_name

Copies in.obj to out.obj changing the colour of each object
in the file.

  set_object_colour in.obj

Prints the colour of each object in the file.



		subdivide_polygons
		------------------

  subdivide_polygons  input.obj  [output.obj]  [n_polygons]

Subdivides any polygons in the file.  If the output file is not
specified, the input file is overwritten with the newly subdivided
objects.  

If n_polygons is specified, the polygons will be resampled to that
size.  Otherwise, the number of polygons in the output will be four
times the input size.