NOTE: This file is autogenerated from the Geomview manual. For references to things not in this file, see the manual. The manual is distributed in the "doc" subdirectory. Mathematica Graphics in Geomview or RenderMan ********************************************* Geomview comes with some Mathematica packages that let you use use Geomview to display Mathematica graphics. Mathematica is a commercial mathematical software system available from Wolfram Research, Inc. There are two ways to do this. 1. Use Mathematica to write a graphics object to a file in OOGL format or in RIB format. 2. Use Geomview as the default display for all 3D graphics output in Mathematica. You can also use these packages to save Mathematica graphics in RenderMan (RIB) format. Since the format of Mathematica graphics objects is different from the OOGL formats, both of these methods involve translating Mathematica graphics to OOGL format. Geomview is distributed with a Mathematica package which does this translation. Before doing either of the above you must install this package. Using Mathematica to generate OOGL files ======================================== The package `OOGL.m' allows Mathematica to write graphics objects in OOGL format. To use it, give the command `<< OOGL.m' to Mathematica to load the package. The `WriteOOGL[FILE,GRAPHICS]' command writes an OOGL description of the 3D graphics object GRAPHICS to the file named FILE. This package also provides the `Geomview' command which sends a 3D graphics object to Geomview. The first time you use this command it starts up a copy of Geomview. Later calls send the graphics to the same Geomview. There are two ways to use the `Geomview' command. `Geomview[GRAPHICS]' Sends the 3D graphics object GRAPHICS to Geomview as a geom named `Mathematica'. Subsequent usage of `Geomview[GRAPHICS]' replaces the `Mathematica' object in Geomview with the new GRAPHICS. ``Geomview[NAME,GRAPHICS]'' Sends the 3D graphics object GRAPHICS to Geomview as a geom named NAME. You can use multiple calls of this form with different names to cause Geomview to display several Mathematica objects at once and allow independent control over them. % math Mathematica 2.0 for SGI Iris Copyright 1988-91 Wolfram Research, Inc. -- GL graphics initialized -- In[1] := <"riemann"] This displays the graphics `%3' on the remote host named `riemann'. `Geomview' recognizes the string `"local"' as a value for `$DisplayHost'; it forces the graphics to be displayed on the local machine. In addition to knowing the name of the machine you want to run Geomview on, the `Geomview' needs to know the type of that machine (SGI or NeXT). By default, `Geomview' assumes that it is the same kind of computer as the one you are running Mathematica on. The `MachType' option lets you explicitly specify the type of the `DisplayHost' computer; it should be one of the strings `"sgi"' or `"next"'. You can use `SetOptions' to change the default `DisplayHost' and `MachType'. For example, In[4] := SetOptions[Geomview, DisplayHost->"riemann", MachType->"sgi"] arranges for `Geomview' to run Geomview on an SGI workstation named `riemann'. Transporting Mathematica Files to Geomview by Hand -------------------------------------------------- The auxilliary function `WriteChunk' is for those who can only use Mathematica on a non-Unix machine (Mac, PC) or a Unix machine that is not on a network with an SGI or NeXT. `WriteChunk[FILE, GRAPHICS]' generates a file named FILE which contains the graphics object GRAPHICS in the format accepted by `math2oogl'. You can transfer that file to a computer that has Geomview installed on it and then use the programs `math2oogl', `oogl2rib', and `geomview' directly from the shell. These programs are distributed in the `bin/sgi' (on SGIs) or `bin/next' (on NeXTs) subdirectory of the Geomview directory, and may have been installed so that they are on your `path'. In[1]:= < mma.oogl to convert it to the OOGL file `mma.oogl' which you can then view using Geomview. This is the equivalent of the `WriteOOGL' command. For a result equivalent to the `Geomview' or `Show' commands, type math2oogl -togeomview Mathematica geomview < mychunk The `WriteRIB' command can be emulated from the shell as math2oogl < mychunk | oogl2rib -n mma.tiff Details of the Mathematica->Geomview Package ============================================ The `OOGL.m' package uses the external program `math2oogl' to convert `Graphics3D' objects to OOGL format, because a compiled external program is able to do this conversion many times faster than Mathematica. The converter will sometimes handle colored SurfaceGraphics objects correctly that Mathematica does not handle correctly, which means that Geomview[object] sometimes works where Show[object] will give errors. The converter supports the `Polygon', `Line', and `Point' graphics primitives, `RGBColor Graphics3D' directives, and `SurfaceGraphics' objects with or without `RGBColor' directives, and lists of any combination of these. It silently ignores all other directives. The Mathematica to RenderMan conversion is actually a two-step process: Mathematica->OOGL (math2oogl), and OOGL->RenderMan (oogl2rib). The math2oogl program has only been tested on SGIs and NeXTs, but could theoretically compile on any machine. The oogl2rib program depends on the OOGL (Object Oriented Graphics Language) libraries, which now only exist on SGI and NeXT machines. In the `WriteOOGL' and `WriteRIB' commands, filename can either be a string containing a filename, an `OutputStream' object, or a string starting with a `!' to send the output to a command. Object can be a `Graphics3D' object, a `SurfaceGraphics' object, or a list of these. The packages work best with Mathematica 2.0 or better. With version 1.2, the Geomview display is always on the local host. Installing the Mathematica Packages =================================== If Geomview is properly installed on your system according to the instructions in *Note Installation::, then the Mathematica-to-Geomview packages should work as described here; there should be no need for additional installation procedures. In practice, however, it is sometimes necessary to taylor the installation of the Mathematica packages and/or of Geomview itself to suit the needs of a particular system. This section contains details about how the installation works; if the Mathematica-to-Geomview connection does not seem to work for you after following the Geomview installation procedure, consult this section to see what might need to be fixed. In this section, the phrase *Geomview installation* refers any of the procedures in *Note Installation::. The way the Mathematica packages work and are installed is the same regardless of whether you have one of the binary distributions or the source distribution. 1. The relevant mathematica files are `OOGL.m', `Geomview.m', and `BezierPlot.m'; Mathematica must be able to find these files. They are distributed in the `$GEOMROOT/mathematica' subdirectory of the binary distributions, and in the `$GEOMROOT/src/bin/geomutil/math2oogl' subdirectory of the source distribution. These files need to be in a directory that is on Mathematica's search path. You can look at the value of the `$Path' variable in a Mathematica session on your system to see a list of the directories on Mathematica's search path. The Geomview installation procedure puts copies of the Mathematica packages into a directory that you specify (`MMAPACKAGEDIR'). This should ensure that Mathematica can find them. Alternately, you could arrange to append the pathname of the Mathmematica package subdirectory of the Geomview distribution to the `$Path' variable each time you run Mathematica. 2. The package `OOGL.m' needs to be able to invoke the programs `geomview', `math2oogl', and `oogl2rib'. The Geomview installation procedure installs these programs into a directory that you specify for executables (`BINDIR'). Ideally, this directory should be on your shell's `$path'. More specifically, it should be on the `$path' of the shell in which Mathematica runs; the directory `/usr/local/bin' is usually a good choice. You can see the list of directories on this path by giving the command `!echo $path' in Mathematica. If for some reason you can't arrange for `geomview', `math2oogl', and `oogl2rib' to be in a directory on the shell's `$path', you can modify `OOGL.m' to cause it to look for them using absolute pathnames. To do this, change the definitions of the variables `$GeomviewPath' and `$GeomRoot', which are defined near the top of the file. Change `$GeomviewPath' to the absolute pathname of the `geomview' shell script on your system. Change `$GeomRoot' to the absolute pathname of the `$GEOMROOT' directory on your system. If you do this, you should also make sure there are copies of `geomview', `math2oogl', and `oogl2rib' in the `$GEOMROOT/bin/sgi' (on an SGI) or `$GEOMROOT/bin/next' (on a NeXT) directory. 3. The `geomview' shell script, which `OOGL.m' uses to invoke Geomview, needs to be able to find the geomview executable file (which is called `gvx' on the SGI and `Geomview.app/Geomview' on the NeXT). The Geomview installation procedure should have been taken care of this, but if your Mathematica session doesn't seem to be able to invoke Geomview, it's worth double-checking that the settings in the `geomview' script are correct.