3D-Modelling

# 3D Graphics Modelling and Rendering mini-HOWTO

## Dave Jarvis

v1.1, 27 March 2001

Details download and installation instructions for a graphics rendering and modelling development environment using RedHat Linux.

## 1. Introduction

- 1.1 Preamble
- 1.2 Modelling vs. Modeling
- 1.3 Copyright Information

## 2. Background Information

- 2.1 The Graphics Library
- 2.2 The Graphics Modeller
- 2.3 The Graphics Renderer

## 3. Installation Instructions

- 3.1 Warning
- 3.2 Download the Software
- 3.3 Install the Graphics Library
- 3.4 Install the Graphics Renderer
- 3.5 Install the Graphics Modeller
- 3.6 Clean Up

## 4. Miscellaneous Information

- 4.1 Lighting
- 4.2 Tutorials

## 5. Related Links

- 5.1 Graphics Libraries
- 5.2 Graphics Renderers
- 5.3 Graphics Modellers
- 5.4 Miscellaneous Links

## 6. Acknowledgements

## 1. Introduction

## 1.1 Preamble

This document will guide you through the steps used to install and configure an environment for modelling and rendering three-dimensional graphics using Linux. In this section you will also find information in laymans terms about the required components and how they piece together. The installation section is purposely minimal; merely the quick and dirty steps needed to take to get up and running (if it doesn't work, more information is available). For those that want more information about the software components and what they do (in general), please continue reading.

There are, at the minimum, three software packages you'll need in order to get up and running. These are as follows (in the order they are explained, not the order they are installed):

- a graphics library;
- a graphics modeller;
- a graphics renderer.

## 1.2 Modelling vs. Modeling

The spelling modelling is Canadian. The spelling modeling is American. The original author of this document is Canadian. ;-)

## 1.3 Copyright Information

Copyright © 2000-2001 Dave Jarvis

This document may be reproduced in whole or in part, without fee, subject to the following restrictions:

- the copyright notice above and this permission notice must be preserved complete on all complete or partial copies;
- any translation or derived work must be approved by the author in writing before distribution;
- if you distribute this work in part, instructions for obtaining the complete version of this manual must be included, and a means for obtaining a complete version provided;
- small portions may be reproduced as illustrations for reviews or quotes in other works without this permission notice if proper citation is given.

## 2. Background Information

The content of this section exists only to describe, in general, the three main components required for three-dimensional modelling and rendering with a Linux-based system.

## 2.1 The Graphics Library

A graphics library consists of the most basic tools used for manipulating graphical images. Think of all the things needed to build a house: wiring, plumbing, wood, bricks, and such. The graphics library can be thought of as not these items, but rather the tools used create such items. After all, wire, metal tubes, planks, and bricks don't magically appear; rather they are created and formed as entities unto themselves. On a similar note, graphics don't magically appear on the screen -- typically they consist of lower-level graphics primatives (lines, rectangles, and individual pixels, for example).

So the graphics library, then, can be thought of as the low-level graphics primatives used to build more complex objects (spheres, boxes, complex polygons, etc.). Those complex objects are then used to build even more complicated shapes and figures.

The graphics library installed was the freeware implementation of OpenGL called Mesa.

## 2.2 The Graphics Modeller

Since the graphics renderer is, ideally, completely hidden from the end-user, we'll deal with that last (besides which, modelling is the next logical step in keeping with my house-building analogy). However, when it comes to the actual installation, a graphics modeller relies on the renderer already being installed.

If the graphics library is akin to the tools used to build the tools used to build a house (!), then graphics modellers can be thought of as the tools used to build the blueprints for the house -- sophisticated blueprints, as modellers let you dictate exactly where the wiring, plumbing, wood panels, bricks, and forth are supposed to go. Furthermore, they let you pick the style of panelling and the colour of the bricks you desire.

The graphics modeller installed was the freeware package called The Mops, which produces RenderMan-compatible files.

## 2.3 The Graphics Renderer

In keeping with the house-building analogy, the graphics renderer is then the construction workers. Once you have the blueprints and materials ready to go, you need something to actually build the house so it appears how it was designed. The graphics renderer is given information (i.e., the blueprints in the form of a RenderMan-compatible file, or equivalent) from the the modeller to produce the final result.

Just as the graphics modeller needs the graphics renderer before it can be installed, the renderer relies on the graphics library being installed beforehand.

The graphics renderer installed was the Blue Moon Rendering Toolkit which uses RenderMan files.

## 3. Installation Instructions

Keep in mind that these are brief instructions; a quick summary of the more important details you'll find listed in README files for the corresponding software packages. It is, by no means, a substitute for actually reading those files (as they contain copyright information and other instructions not necessarily covered by this document).

## 3.1 Warning

First, let it be known that this document only covers how to get up and running using RedHat v7.0. Whenever given the choice as to which software package to download, please make sure it is compatible with the flavour of Linux you happen to be running.

Second, please only send E-mail if you have information that would be helpful to other people who might read this document (such as explaining how to install other tools, pointers to other tutorials, missing steps grammar and/or speling mistakes and/or tpyos, etc.). If software doesn't compile, or you can't figure it out, please read its accompanying documentation. Please understand that your system may be completely different, and as such debugging problems via E-mail across the Internet is not a task anyone enjoys. ;-)

Third, these are software packages that installed without any severe hitches (read: severe headaches). In the Related Links section, there are alternate software packages along side the ones covered below. Note that just because a given software package is not covered in depth does not mean it is any worse (or better) than those chosen to install.

Good luck!

## 3.2 Download the Software

Before you begin, you will need a web browser and Unix shell. If you don't know how to use a shell [bash, ksh, etc.], you're own your own (although instructions are given in both English and shell commands).

Unless otherwise specified, all instructions are to be carried out as `root`.

1. Create a new directory `/usr/local/archives` for the packages:

   > `

   >     mkdir /usr/local/archives

   > `

2. Download the following packages (in .tar.gz form) into the newly created directory (homepages are given, as well as links to download pages, and minimum software version):
   - Mesa Graphics Library v3.4.1: www.mesa3d.org/download.html
   - Blue Moon Rendering Toolkit v2.6beta: www.bmrt.org/BMRTdownload/index.html
   - The Mops v0.42d: www.informatik.uni-rostock.de/~rschultz/mops/download.html

## 3.3 Install the Graphics Library

Old versions of `tar` do not support the `z` argument. For those systems, leave out the `z` argument and use `gunzip` on the file before using `tar`.

1. Change to the `/usr/local/archives` directory:

   > `

   >     cd /usr/local/archives

   > `

2. Extract Mesa (substitute version number where required):

   > `

   >     tar zxf MesaLib-3.4.1.tar.gz
   >     tar zxf MesaDemos-3.4.1.tar.gz

   > `

3. Change to the `MesaLib` subdirectory:

   > `

   >     cd Mesa-3.4.1

   > `

4. Configure, make, and install Mesa with the following sequence of commands:

   > `

   >     ./configure; make; make install

   > `

5. Edit `/etc/ld.so.conf`, and ensure you have a line that reads:

   > `

   >     /usr/local/lib

   > `

6. Run the dynamic library configuration program:

   > `

   >     ldconfig

   > `

## 3.4 Install the Graphics Renderer

1. Return to the `/usr/local/archives` directory:

   > `

   >     cd ..

   > `

2. Extract the Blue Moon Rendering Toolkit (substitute version number where required):

   > `

   >     tar zxf BMRT2.6beta.linux-glibc2.tar.gz

   > `

3. Change to the `BMRT` subdirectory:

   > `

   >     cd BMRT2.6

   > `

4. Copy files to appropriate destination directories:

   > `

   >     cp bin/* /usr/local/bin/
   >     cp lib/lib* /usr/local/lib/
   >     cp include/* /usr/local/include/

   > `

5. Make a directory for the shaders, ensure it is world-writable, then copy the shader files into it:

   > `

   >     mkdir /usr/local/shaders
   >     chmod 777 /usr/local/shaders
   >     cp shaders/*.sl* /usr/local/shaders/
   >     cp shaders/*.h /usr/local/shaders/
   >     cp examples/*.sl* /usr/local/shaders/
   >     cp examples/*.h /usr/local/shaders/

   > `

6. Edit the system login profile (`/etc/profile` or equivalent), and add the line:

   > `

   >     export SHADERS=.:/usr/local/shaders

   > `

7. Copy the `.rendribrc` file to each user's home directory.

If anything goes wrong, please consult the `README` file that accompanies the Blue Moon Rendering Toolkit, or visit their website.

## 3.5 Install the Graphics Modeller

The Mops may be installed on a per-user basis, or on a system-wide basis by root (or equivalent). In this example, it is installed using a non-administrative account, which should yield positive results. Note that the compile failed during the install (missing a C header file), so the precompiled binaries (compatible with RedHat v6.0, your system may vary) were installed, as follows:

1. Change to one directory above where you'd like The Mops to reside. For example, if `/usr/local/mops` was desired, then issue the following command:

   > `

   >     cd /usr/local

   > `

2. Extract the mops (substitute number where required), then change into its directory:

   > `

   >     tar zxf /usr/local/archives/mops-0.42d-BMRT26-linux.tar.gz
   >     cd mops

   > `

3. Move the following files from `/usr/local/mops/src` to `/usr/local/mops`:

   > `

   >     mv src/crtmopssh.sh .
   >     mv src/mfio.so .
   >     mv src/mops .

   > `

4. Copy the `.mopsrc` file to the home directory of each user wanting to run The Mops. For example, the user "jane" would need the following commands run:

   > `

   >     cp src/mopsrc /home/jane/.mopsrc

   > `

5. Create `/usr/local/lib/mops` and move the buttons and shaders:

   > `

   >     mkdir /usr/local/lib/mops/
   >     mv buttons/* /usr/local/lib/mops/
   >     mv shader/*.sl* /usr/local/shaders/

   > `

If anything goes wrong, please consult the `README` and `Setup.txt` files that accompany The Mops, or visit their website.

Log out from `root`. Log in as a regular user, and run The Mops as follows:

> `

>     /usr/local/mops/mops

> `

You may wish to create a subdirectory within `$HOME/mops` called `models` for saving 3D models.

## 3.6 Clean Up

Now that the installation is complete, you can remove from your system all files that you no longer require (substituting version numbers where required).

> `

>     cd /usr/local/archives/
>     rm -rf BMRT2.6
>     rm -rf Mesa-3.4.1

> `

Note: Be cautious when using `rm -rf` ... make sure you are in the correct directory, and the files and/or directories you wish to delete are present.

## 4. Miscellaneous Information

Instead of a frequently asked questions section, here is information about some of the (almost embarassing) problems faced.

## 4.1 Lighting

The most frustrating problem, initially, was trying to figure out why everything was black -- and then how to actually light objects up. In these "virtual worlds" where you are modelling objects, the worlds are created from scratch. There is no light in the world until you actually put a light source in it! The light sources then shine a given direction, illuminating things in their path (according to the surface properties of the objects). Make certain that your light source is:

1. pointing (rotated and translated) in the correct direction;
2. intense enough to actually cast discernable lighting.

## 4.2 Tutorials

The most basic thing a person would want to do with modelling/rendering packages is position a sphere on a surface, give it some lighting, and see the result. A decent tutorial should describe that first.

That said, The Mops has a wonderful first tutorial.

## 5. Related Links

## 5.1 Graphics Libraries

Mesa - An OpenGL-compliant Graphics Library.

## 5.2 Graphics Renderers

BMRT - The Blue Moon Rendering Toolkit.

POV-Ray - The Persistence of Vision Raytracer.

## 5.3 Graphics Modellers

The Mops - A 3D modelling package that uses BMRT.

Blender - Freeware modelling and rendering suite of tools.

## 5.4 Miscellaneous Links

Here are some links that don't really fit into any other category, yet are still worthwhile checking out if you are seriously considering using your Linux computer as a 3D modelling and rendering machine.

3D Software for Linux - Contains most (if not all) links in this document and then some.

3D Modelling Software for Linux - Links to software packages chiefly related to modelling.

3D Modelling and Rendering using Linux - A comprehensive site with articles and software that explains what this document summarizes.

## 6. Acknowledgements

I would like to extend a heart-felt thanks to the developers of the software packages detailed in this document. The quality of their products is of a commercial level, yet they keep the spirit of free software alive. Well done!