View Full Version : The Houdini Apprentice FAQ

01 January 2003, 06:31 AM
The Houdini Apprentice FAQ

This is a copy of the FAQ maintained by moderators and Houdini Apprentice users at 3DBuzz ( The latest version can be found at:

I'm reposting it here with permission from MCronin. For clarification requests, additions, and corrections you can PM me.

This FAQ is unofficial, it is maintained by users, and has no direct affiliation with Side Effects Software Inc, or


Section 1: General
Section 2: Technical Issues
Section 3: Tips

01 January 2003, 06:32 AM
Section 1: General

1.1) What is Houdini?

Houdini is a high end Computer Animation and Visual Effects package. Houdini's primary domain is film, but it is also used in game development. Houdini includes tools for modeling, animation, particle effects, motion and audio editing, shading, lighting, compositing, and has a built in production renderer called Mantra.

1.2) Who makes Houdini?

Houdini is produced and distributed by Side Effects Software Inc. also known as SESI. Side Effects has offices in Toronto, Ontario and Santa Monica, California. SESI can be reached on the web here:

1.3) Who uses Houdini?

Many A-list effects houses and game developers use Houdini in production. Digital Domain, Sony Pictures ImageWorks, Rhythm and Hues, WETA Digital, SquareSoft, Cinesite, Jim Henson's Creature Shop, Black Box Digital and Asylum are just a few of the companies using Houdini. In 2002, all three films nominated for Best Visual Effects Academy Awards incorporated Houdini into their pipeline.

1.4) How much does Houdini cost?

Houdini is a professional 3D Animation package built for production work, therefore, commercial licenses are expensive. Houdini comes in several flavors of varying capabilities. For a complete list of package features and pricing visit: and

1.5) What is Houdini Apprentice?

Houdini Apprentice is a free learning edition of Houdini that gives students and hobbyists access to the full range of tools within the entire Houdini product family with few limitations. The Houdini Apprentice program is designed by Side Effects to allow users the opportunity to fully learn to use their software and spread awareness of the Houdini Product Family. You can read more about the details of the Apprentice Program here:

1.6) When did the Apprentice Program start?

July, 2002

1.7) When will the Apprentice Program end?

Side Effects intends to support the program indefinitely

1.8) What operating systems does Houdini Apprentice support?

Houdini Apprentice supports Windows NT-SP 6/2000/XP, RedHat Linux 6.x, RedHat Linux 7.x, Irix, and Solaris. Houdini Apprentice will run on other Linux variants (Mandrake, SuSe, Debian) though not officially supported by SESI. Houdini does not support OSX, Power PC Linux distributions, Windows 95, 98, or ME.

1.9) What are the system requirements of Houdini Apprentice

As with any professional 3D software, the better equipped your computer is, the better able you will be to use the software. Complete list of minimum recommended requirements can be found here: The main concern should be your video card. A card with 3D Open GL hardware acceleration is required. At least an Nvidia GeForce 2 based card should be used, professional video cards such as the Fire GL series, Wildcat series, or Quadro series are strongly recommended. Houdini Apprentice requires Open GL Extensions beyond those supported by most consumer level cards and thus is not well supported even by some late model consumer cards. In the future non Nvidia based consumer cards may better support Houdini Apprentice through driver revisions. If you are using a card that does not support Houdini Apprentice well, please contact the manufacturer of your video card and request better support for Houdini Apprentice.

1.10) Where can I get Houdini Apprentice?

Houdini Apprentice, and the learning tutorials can be ordered by mail for the cost of shipping directly from Side Effects: or if you are in the Toronto or Santa Monica area, you can pick the CDs up from their offices directly. On the web, the latest versions of Houdini Apprentice can be downloaded for all platforms at:

1.11) What are the limitations of Houdini Apprentice?

Houdini Apprentice has several limitations that will in no way interfere with your ability to learn the software in it's entirety and use it for non commercial purposes such as creating a demo reel. The limitations include but are not limited to:
Maximum Render Resolution of 640x480
Scenes are saved to a custom non-commercial format
Tiny transparent word marks are placed in the lower right corner of each editor pane. Click here for an example (
A small watermark is placed in the lower right corner of each rendered image Click here for an example (
Geometry and scene export options are limited to formats internal to Houdini Apprentice
Third party rendering solutions such as Mental Ray or Renderman Compliant Renderers such as Pixar's Renderman can not be used with Apprentice
The Houdini Developer's Toolkit cannot be licensed under the Apprentice Program, Although all other products, Master, Escape (soon), Halo, and Select can be.
Apprentice licenses must be renewed by the user every 30 days.
Apprentice licenses are Node Locked, therefore, Distributed Network rendering is not possible.
Although Apprentice files (file.hipnc) can be opened by commercial Houdini licenses, the commercial Houdini session will revert to a non-commercial session. Files created with a commercial Houdini License can be opened in Apprentice.

1.12) So whatever I make with Apprentice is useless?

Absolutely not. The files you create in Houdini Apprentice can be used for your own non-commercial purposes including enhancing your portfolio and creating a demo reel. Should you decide to buy a Houdini License, Side Effects will do a one time conversion of all your non-commercial work to Houdini's commercial format (file.hip).

1.13) Where can I learn to use Houdini Apprentice?

The best place to start is with the Tutorials.pdf file right within Houdini Apprentice's help menu. Next you could try downloading the Houdini Apprentice program tutorials from:

Currently, Real Player is required to view the above tutorials, but they will soon be posted on the Houdini Community site listed below in DIVX format.

Side Effects has set up a main community site that includes additional tutorials, example files, forums, a job board, news, mailing lists and contests here:

The 3D Buzz online class offers a fantastic, interactive way to learn Houdini with professional instruction. It includes lectures, quizzes, tests, assignments, projects, and a class forum. Read more here:

Lastly, is an independent Houdini user community run by artists from Digital Domain. You will find forums and additional tutorials and information there as well as at

1.14) Are there any books about Houdini available?

Not at this time, however there may be in the future.

1.15) I've heard you need to be of Einstein level intelligence to use Houdini...

Not true. Houdini works differently than other 3D applications, but with proper instruction from Side Effects and 3D Buzz you will find it quite intuitive and very powerful.

1.16) Does Houdini Apprentice have feature X from Brand Y software?

Houdini has a very comprehensive toolset, enabling you to create anything you can conceive. Because of the way Houdini operates on first glance you may think it's features are lacking. Most effects can easily be created in Houdini with some thought and careful planning. For instance, Houdini does not have hair, cloth, or muscle simulation plug-ins, but these are all effects that can be achieved with Houdini's toolset.

1.17) Does Houdini support GI, Radiosity, IBI, HDRI, Caustics, SSS...

Houdini currently only supports these features through third party renderers such as Mental Ray and Pixar's RenderMan, and support is not available through Apprentice. There are a myriad of tutorials on the net for faking such effects which can be applied to Houdini. Houdini's Mantra renderer, although currently lacking these features, is a genuine production render which has been used to create highly realistic effects for film. Mantra coupled with Houdini's Shader programming tools will allow you to create images of a quality rivaling the output of any other renderer available.

01 January 2003, 06:32 AM
Section 2: Technical Issues

2.1) How do I install Apprentice?

Windows Simply execute the installer and follow the prompts. It should be noted that because Houdini is heavily rooted in Unix that you may experience problems if you install to a path that contains spaces within the first 6 characters. By default Houdini installs to C:\Program Files\Side Effects Software. Right away this could be a problem. Change the Path to C:\Houdini\ or something similar. This is important. Read more about this problem in the section below about spaces in directory names and Houdini

Linux Note: For RedHat 6.X and 7.X, follow these instructions. If you are using Mandrake, Debian, Slackware, GenToo, SuSe, etc. and are having problems, follow the instructions in further down in the FAQ entitled "Installing Houdini on non RedHat Linux Distros".

Unpack the archive to a directory maintaining it's sub folder structure. In your console cd to the directory where you unpacked the archive and type:


to execute the installer from the current directory. Should you not be able to start the installation, you should check the permissions of the file and make certain you have permission to execute it. Once the installer begins, follow the on screen prompts.

For further info regarding installation issues, check the "Getting Started" PDF file here:

2.2) How do I run Houdini?

Windows Simply click the Houdini Master shortcut in your Start Menu. You will also notice shortcuts to the other products in the Houdini family which you can license and use. Additionally, if you check the \bin directory in your Houdini installation path you will find many smaller tool executables have installed. These tools include things like image viewers, geometry viewers, and a simple paint program. You can run any of these tools by clicking on them, or by creating shortcuts to them elsewhere on your system.

Linux Open a terminal and type 'csh' at the prompt to change to a C Shell. Type 'cd /usr/hfs5.5' to navigate to your Houdini installation. Type 'source houdini_setup' to initialize the Houdini environment. Finally type 'houdini' to run Houdini Apprentice.

Should you not want to type all that every time you want to run Houdini, you can create an .sh script and an alias to initialize and run Houdini with a single command or from a shortcut. Copy the following code into the editor of your choice and save it somewhere in your system path (usr/bin) as ''

#!/bin/csh -f

cd /usr/hfs5.5
source houdini_setup

Now if you just type '' at a prompt, Houdini will initialize and start. You can create a simple alias or a graphical icon for the script to run Houdini from your desktop or programs menu.

As with Windows, in addition to the standard Houdini family products, you will find the same small tool programs in the /bin directory in your Houdini path.

2.3) I'm a Linux noob! Where can I learn more?
are both good resources.
If you have Houdini/Linux specific questions, ask in the forums
It's also a good idea to pick up a book like "Red Hat Linux 7.3 Secrets"
or some other book for Linux beginners.

2.4) How do I license Apprentice?

You should have a NIC (Network Adapter) installed in your machine, and it should have a unique IP address (192.168.0.XX) and unique name. 'localhost' is not acceptable for Linux installations. Also, you should be connected to the internet. When you start Apprentice for the first time, it will ask if you'd like to install a non-commercial license. Click the link and the license administrator will contact Side Effects and install a license for your specific machine. No personal information will be submitted to Side Effects during the process.

2.5) How do I license Apprentice if I DON'T have an internet connection?

You can license a machine that is not connected to the internet, however, you will need access to the internet through a web browser through some other PC or device. On the machine you would like to license, start Houdini. When the license administrator appears, click on the "Server Information" tab and jot down your computer name and server code. Go to enter the info an it will generate a license for you. Follow the instructions on the page to install the licenses. You can license the other Houdini family products using the same method.

2.6) My license says it's expired even though it's good for another couple weeks, days, etc

Double check your system date and time.

2.7) When I start Houdini it asks me repeatedly to install a license, even though I have one...

This problem seems to be specific to Windows and as of yet there is no known answer as to what causes it. There is only one solution we know of that seems to work, and that is to start the license servers manually every time you want to run Houdini. Follow this process.

Set your Houdini License Server and Houdini License Client to manual in Control Panel->Administrative Tools->Services by right clicking on them and selecting properties.

Copy and paste the following code into notepad and save it as StartHoudini.bat. You may have to edit the path in the code to match your current Houdini installation path.

NET START|FIND "Houdini License Server"
GOTO answer%errorlevel%
NET STOP "Houdini License Server"
NET STOP "Houdini License Client"
NET START "Houdini License Server"
NET START "Houdini License Client"
cd C:\Program Files\Side Effects Software\Houdini 5.5.197\bin

What this batch file will do, is start the servers and start Houdini if they are down, and stop the servers if they are up. You can place this .bat file anywhere on your system, and create a shortcut to it to run Houdini from your desktop or start menu.

2.8) My computer has a NIC, unique name and IP, and I'm connected to the internet, but I cannot get a license...

Check the settings for your firewall, and even if you don't have firewall software installed, keep in mind that some OSes have built in firewalls. If you don't know how to administer a firewall properly, simply disable it momentarily to obtain a license. If all else fails, follow the instructions above for installing a license if you don't have a net connection. If you follow the instructions above, and cannot get through to the licensing page in your browser, it could mean Side Effects' licensing server is temporarily down.

2.9) I read everything in this FAQ, followed all the directions, and I still can't get a license working

Go to the Technical Forum at and start a new thread that specifically states what the problem is. If you can get the license manager screen open and get an error message, paste the error message along with the info that shows up when you go to view->diagnostic information in the license manager into the thread.

01 January 2003, 06:33 AM
2.10) What's the difference between a "node-locked" and "floating" license?

A node locked license is a license that is for a specific machine. Floating licenses can be served and checked out by machines across a network. Houdini Apprentice Licenses are node locked.

2.11) Does Houdini Support Network rendering?

Houdini Supports full distributed rendering so long as you have a COMMERCIAL floating license. Houdini Apprentice licenses are non-commercial and node locked, so network rendering is not possible.

2.12) Houdini runs pretty slow, what can I do to get better performance?

As outlined in the system requirements, a better machine equals better performance. If you can run a professional graphics card such as a Quadro, Wildcat VP or Fire GL do so. The next best thing are cards with Nvidia based chip sets. Houdini is much less resource intensive than other professional 3D applications, but more RAM and big swap files always help. If you can put your swap file on a disk other than the one your operating system is installed to, do so. Things you can do to improve performance: Make sure your video drivers and service packs are up to date.
Close other software while Houdini is running. The more resources and processor time Houdini has available, the better it will run.
Make sure you don't have other widows set to be "on top' while Houdini is running even though they are minimized.
If you aren't using a professional graphics card, and you have a problem with the GUI redrawing itself slowly, stow the toolbar.
Try disabling "Double Buffering" and "Draw Lines Smoothly" from within Houdini in Edit->Preferences->General.
If you normally run at high resolutions with high refresh rates, try dialing it down to 1280x1024, 1280x960, or 1024x768. Try lowering your refresh rate, and running at 16bpp color depth.
If your video card has anti-aliasing options or other such features enabled through it's control panel, disable them.
If your video card has toggles for "Hardware Overlays", "Buffer Region Extensions", "Dual Planes" or "Double Buffering" in it's Open GL control panel, try enabling them.
If all else fails, you can run Houdini in software mode. Instructions for this are in the next answer.

2.13) How do I run Houdini Apprentice in OpenGL software mode?

Under Windows XP, to set environment variables, right-click on My Computer and choose Properties. Switch to the "Advanced" tab and click on the "Environment Variables" near the bottom. Then under "System Variables", push the "New" button. Finally, type in "HOUDINI_OGL_SOFTWARE" (without the quotes) inside "Variable Name:" and put a "1" (without the quotes) inside "Variable Value:". Now just hit the OK button until you're out. For Windows NT and Windows 2000 systems, the process is similar.

2.14) Houdini runs pretty nicely except when I use feature X...

Try using the "Cooking Controls" in the upper right corner of your workspace. Setting them to "Changes" rather than "Always" means your scene will not be updated in your viewer until you have completed your current action.

2.15) Cooking Controls have no effect on feature X...

Some OPs, such as Capture Paint cannot be affected by Cooking Controls. In these cases you should use visibility SOPs to isolate parts of your geometry to work on.

2.16) How can I optimize my scene for better performance?

You can use visibility SOPs, set your display flags, and use the "See All/One" toggle at the bottom of your viewer pane to isolate the geometry you are actually working with. Additionally, you can use stand in low res geometry for viewport display and set your render flags to your final high res geometry. You can also lock OPs in your network to prevent Houdini from constantly re-evaluating the entire network on every change. Setting your near and far clipping planes in your display options only as far and as close as actually need to "see" is a good idea. Lastly, you can append a TriStrip SOP to the end of your model network and set it's display flag for better performance in your object viewer.

2.17) I'm using a consumer card, I've tried all the tips and performance is still poor...

If you are having performance problems even after trying all the recommendations, you can adjust your workflow to speed things up a bit. As much as possible, try to work in a single perspective view pane and/or network editor. Also, try not to make adjustments with the Parameters page for the current OP open. The Parameters Page will update as changes are made in the scene, and this can be very detrimental to performance on some consumer cards.

2.18) VEX Shaded mode is SUPER slow...

VEX Shaded mode is used to display your shaders real-time in a viewport. Houdini has to do a bunch of software calculations every frame to accomplish this, so performance is sub par on even high end workstations. As hardware advances, performance in VEX Shaded mode will improve dramatically. For now, it is recommended you do not try to work in VEX Shaded mode. If you'd like quick previews of your shaders in your scene, you can do a quick preview render or try using the Render State.

2.19) Every time I do anything in Houdini, the GUI and all the icons redraw themselves, and I can't continue working until they stop...

This is a problem with consumer level video cards. The solution is to stow the tool bars. The interface may still redraw slowly when changing editors, but once in an editor, Houdini should be very responsive. All the tools in the bar can be accessed much easier through the tab menu and hot keys.

Note: This problem seems to be minimized in newer versions of Apprentice (5.5.230+) and newer Nvidia detonator drivers (41.xx)

2.20) Is it possible to make the Transform Manipulator handles thicker or easier to grab?

Not at this time. It may be submitted to Side Effects as a request for enhancement in a future release. For now, if you are having trouble picking the handles, pressing space+g to home the selected geometry may make the handles easier to pick. It also seems that this problem is more common on consumer cards. Another thing to try is to run Houdini at a lower screen resolution.

2.21) In my shaded perspective view, I'm seeing little pixel sized holes and artifacts on my surface here and there. What gives?

These artifacts, often referred to as "rendering errors", are a fact of life in Professional 3D applications. No matter what software you use, no matter what hardware you use, you will see them time and again. How many and how often you seem them is dependent on your video card.

2.23) I'm seeing those little holes and artifacts in my renderings, too! And the renderings look jaggy!

You need to tweak the settings in your current renderer (ROP). Upping the "Super Sample" parameter on the "Standard" page and trying the different filter methods on the "Specific" page are good places to start. Rendering options in any program can be daunting, so it's highly recommended you browse the "Outputs" PDF from Houdini's help menu to find out how to use all the features of Mantra's ROP.

2.24) In my shaded perspective view, I'm seeing objects clip through each other...

Try adjusting your near and far clipping planes in the display options and/or your Camera parameters.

2.25) In Smooth Wire Shaded and Flat Wire shaded, I see my wireframe clipping through the surface and/or the wireframe seems offset from the surface

Try adjusting your near and far clipping planes in the display options and/or your Camera parameters.

2.26) The scene files for the "Tutorial and User Guide" PDF in the Apprentice help menu are missing..

You can download the missing files directly from Side Effects, here:

2.27) I've searched the help files, but cannot find info on feature X. Y, or Z

Houdini is being constantly updated and it's not possible to keep the documentation up to date with the current build. You can, however, easily find help on every Houdini feature using Houdini's online help system. In the parameters page of every OP you will notice a question mark near the top. clicking on the question mark will display a lengthy help pop-up on the features and usage of that particular OP. Additionally, Houdini's status bar will offer tips on what to do in blue text at the top of the main window while you are working.

2.28) Where can I find help on Scripting and Expressions?

Change one of your panes to a textport by pressing ALT+7. At the prompt type help or exhelp. These will list all the commands available to you for scripting and expressions. Typing help <command name> or exhelp <command name> will display help for the specified command in the textport. Additional help can be found in the "Scripting" PDF from Houdini's help menu, and there is a section on scripting in the "Tutorial and User Guide" PDF. Houdini can be further customized through TCL/TK.

2.29) What is TCL/TK?

TCL and TK are standardized scripting languages, ala Perl or HTML. They are not part of Houdini, but can be used with Houdini. TCL stands for Tool Command Language, and TK is the X Toolkit. TCL allows you to write functional scripts, and TK allows you to give them a visual interface. More info on TCL and TK can be found here: You do not need to learn TCL and TK to use Houdini or to create scripts for Houdini. TCL and TK just allow you to further extended Houdini through a widely accepted scripting language.

01 January 2003, 06:34 AM

2.30) Houdini has problems with spaces in the directory structure

Houdini is firmly rooted in the Unix world, and therefore spaces are not allowed in directory names. What Houdini does is truncate directory and file names to an 8.3 format. Any folder name with a space in the first 6 characters is a potential problem for Houdini. So, a folder named:

c:\My Houdini Work\



This is a problem. Houdini will not be able to find this directory or read or write to it.

The real problem comes in with Environment Variables. In a nutshell, an Environment Variable is a keyword that your operating system expands into something else. For instance, you may have an environment variable like this:

TEMP = C:\Documents and Settings\MyName\Local Settings\Temp

The above means anytime you see Houdini using $TEMP/myfile, it's actually saving to C:\Documents and Settings\MyName\Local Settings\Temp. The above is OK because it truncates to:

TEMP = C:\Docum~1\MyName\LocalS~1\Temp

If you had a space in your login name such as:

C:\Documents and Settings\My Name\Local Settings\Temp

It would truncate to:


and cause a problem.

Houdini uses a bunch of these environment variables. You can read more about them in the next section. To avoid potential problems with the default Houdini installation and avoid messing with environment variables there are only a few simple things you should do:

1: Do not use a login that has spaces. Login to Windows as JSmith or J.Smith or J_Smith, but not J Smith.
2. Install Houdini to a directory that has no spaces in it's path. Instead of installing to C:\Program Files\Side Effects..., just install to C:\Houdini\
3. Any folders or files you would like Houdini to have access to should NOT have spaces in the first six characters of their names.

More on environment variables coming soon.

01 January 2003, 06:35 AM
2.31) Installing Houdini on non RedHat Linux distros

If you tried installing Houdini on Linux as outlined above, but got an installation error 712 or similar. Try following these notes courtesy of hypnagogic

How do I install Houdini on Linux Mandrake 9. I'm very new to Linux and installing this app seems impossible. How do I do it?

I keep getting error on line 712 of the 'houdini.install' file

If its failed at that point it looks like the installer script can't find your xterm, which it's trying to start at that point:

$ grep -n xterm houdini.install
712: exec xterm -geometry 80x40 -e $0 THE_REAL_THING nohold

If you have X installed then xterm should be too. You can double-check with the following command as a regular user.

$ which xterm

If the installer is not finding it, yet it is clearly there, then it must be a path issue. Assuming you're not even getting the installer to kick into life, with a failure at line 712, then check your PATH variables with your current terminal/user setup.

I'll quickly cover a few commands here so you can become a little more comfortable when tackling installers like Houdini's, so bear with me. Everyone else feel free to move along.. It's almost Christmas.

Depending on how your terminals are set you may have more or less info telling you who you are and where you are at the command line. This command will tell you who you are logged in as, in case of amnesia:

$ whoami

Now, here's one way to check your path variables.

$ echo $PATH

If '/usr/X11R6/bin' isn't there then the Houdini script won't work, as you appear to have discovered! It probably will be there as a user but I'm also assuming you're logged in as root, as unxetas has suggested that's kind of important to install Houdini . I imagine the xterm is in your path as a regular user, but not it would appear as root. You will need to be logged in to the same directory as the 'houdini.install' script too. You can check your whereabouts anytime with this command. One relevant example from my setup.


Houdini's install script, will, in the absence of 'xwsh', want to use an xterm as root. If xterm isn't in root's path, no joy.

Here's what you should do (Like Houdini there are a number of ways you can solve things!). First become root. I'm assuming you're running as a regular 'joe', 'fred', or 'jason' (Hi Jason!). You should use a user account for day to day use rather than the root account, which is for system stuff, installations and so on.

Apologies if you know all this! There's an easy way to switch to root status without having to log out and log in again. Just open up a terminal and type the following. This should give you an idea how things will look:

martin@flux: ~$ su

So type your root password and watch your prompt change.


Besides 'root' appearing, you'll see the '$' switch to '#'. I'm guessing that's how it is under Mandrake, you may or may not get the path at your prompt (it's been a while since I messed with Mandrake). Now type the following (just the text after the '#'), I've included an example/guess at your output:

root@flux:/home/martin# echo $PATH

Judging by the hassles you're having, unless it's something incredibly obscure, well, you won't be seeing /usr/X11R6/bin listed as a path, just like above. So type the following:

root@flux:/home/martin# PATH=/usr/X11R6/bin:$PATH

Now check your path again (you can press the 'up' cursor key twice to get back to the echo command to save you typing it in again! Then hit return):

root@flux:/home/martin# echo $PATH

That's better! To test it try typing 'xterm' in the same terminal, and without the quotes. A new terminal window will open. So now you should be OK starting an xterm as a root user - via Houdini's installer. You'd need this PATH variable to be in root's .bashrc for the /usr/X11R6/bin path to 'stick' permanently. Now get rid of that test xterm if its still hanging around.

Then cd to the directory that contains your houdini installation script and run her again.

# ./houdini.install

Note the dot (or period if you're from the States ) and then the forward slash. Your telling the Bash shell to run the installer from your current directory. This file needs to be set as executable in order to run. ('chmod +x houdini.install' if it isn't )

Now everything should install just fine, the 'installer' (an xterm window) will launch. Someone has reported Houdini is running fine under Mandrake 9.0, no great surprise, over on Odforce -

I've also posted some installation tips on running Houdini under Slackware 8.1 over on Odforce, under the Linux section, for anyone who may need them. Don't forget to log out as root in your terminal once your done, just type 'exit' without the quotes, or use Ctrl-d. Hitting that key combo a second time will quit your terminal altogether.

Linux, not unlike Houdini I guess, can seem a little strange and alien at first but it becomes more transparent over time, and it's unlikely you'll want to use anything else once it gets under your skin. Stick with it!

01 January 2003, 06:35 AM
2.32) Does Houdini Support Direct X?

Not at this time, and it is doubtful as to whether Direct X will ever be implemented. Houdini is a multi-platform professional production tool. Since most production is done on platforms other than Windows, Houdini must use a multi-platform API (Open GL) for hardware acceleration.

2.33) Does Houdini support Vertex and Fragment (Pixel) Shaders?

Currently these features are only supported through Open GL extensions, and thus are not supported in Houdini. There are several high level shading languages competing for the market right now. Open GL 2.0 will add yet another high level shading language to the market. When Open GL 2 solidifies and is released, we can then probably look forward to Side Effects implementing Vertex and Fragment Shaders, possibly even user programmability within Houdini through VEX Builder.

2.34) My renderings from Houdini are upside down and/or backwards...

This is most commonly seen rendering out of Linux/Irix, and then viewing or manipulating the images on Windows. It also happens if you are outputting tiff files and then manipulating them on an external program that doesn't understand the orientation tag. For example, if you viewed the tiff files generated from Houdini, they are flipped under Adobe PhotoShop but not in PMView. If you encounter flipped images, it's probably best to simply output .tga files instead.

The Formats PDF also has some info on bottom-up vs top-down images:

When images are stored as files, no assumption is made about whether images are stored bottom-up or top-down. Images are simply a sequence of scan-lines. An image is typically displayed using ip the iplay program which by default, displays
the image from bottom-up. If you need to display images as top-down, use fip instead of ip . To set the default behaviour as top-down, set the FLIP environment variable in your .login file:
setenv FLIP
Thereafter, these commands will display images as top-down instead of bottom-up:
icp myImage.tif ip
iplay myImage.tif

2.35) Does Houdini support Pixar's Renderman, Mental Ray, BMRT, Entropy, Air, Render Dot C, etc...

Currently support for these renderers is only available with Houdini Master, and only with full Commercial licenses. Apprentice does not support these renderers and support cannot be licensed as an option with Select, Halo, or Escape.

01 January 2003, 06:36 AM
Section 3: Tips

3.1) What Houdini resources are available on the internet?

Side Effects Software Inc. Makers of Houdini:

The Official Houdini Community Site. Tips, tutorials, downloads, contests, forums, links, and mailing lists. You first stop for all things Houdini:

od[force].net. The unofficial Houdini community. Run by employees of Digital Domain. Great tutorials, shaders, scripts, news and forums:

Visual Paradigms. Houdini community with news, tips, tutorials, downloads and forums:

Techimage. Houdini Apprentice downloads, tutorials, and Houdini Events.

Sydney VisLab. The official, unofficial mirror to the very latest Houdini Apprentice builds. Both CD 1 and 2 available for download on all platforms:

3D Buzz. Fantastic FREE Houdini 101 online class, and General Houdini forums in the 3D software section.

Houdini on IRC. 3D Buzz's Houdini channel:
channel: #Houdini

Houdini Mail Lists. The official Houdini mailing lists.
Note, the lists are low bandwidth, and the main Houdini list is heavily trafficked by professionals and academics. As a new user it is best to ask questions on the "edu" list.

City University of Hong Kong. Tutorials and lectures for Houdini and other 3D applications:

El Kabong: Live Houdini performances and tips for animators:

Sean Lewkiw. Houdini user with some nice tutorials:

BFX. Houdini links, tutorials, shaders, and a gallery:

Digital Producer tutorial on Houdini Particles:

Martian Labs: Producers of fine add-on software for Houdini:

Cam F Productions. Company offering Houdini Shader Downloads:

CGChat. Houdini forum, plus general/other application 3D forums as well:

CG Channel. Large very busy CG hub with forums for specific apps including Houdini:

CG Talk. Large very busy CG hub with forums for specific apps including Houdini:

Companies that use Houdini: Digital Domain (
Rhythm & Hues (
Sony Pictures Image Works (
WETA Digital (
Jim Henson's Creature Shop (
Cinesite (
Composite Image Systems (
Travelling Pictures (
Axyz Animation (

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