PRMan: Installing Pixar's License server on Ubuntu

PRMan price drop

It is a great time in RenderMan land. Pixar will release RMS 19 with the new RIS render technology this fall. That is great news but the real whopper is Pixar's decision to dramatically lower the price of all this sweet candy. That's right, instead of thousands of dollars it has gone down to $495 per license. And the great thing is that there is no differentiation between RenderMan Studio and RenderMan Pro server anymore. A license can drive either product.

This price restructuring brings new opportunities for small VFX studios. But the fun does not end here. Students and hobbyists can now register for a non commercial license for free and there are no limitations in the software or watermarks in the images. There is really no excuse anymore to not try this render engine. The free version will also be available in the fall of 2014.

Pixar licensing

Now that the software is more accessible I like to talk a bit about the licensing system. Paying customers work with floating licenses. Floating licenses have a big advantage. You can install the software on as many machines as you want but it is the license server who dictates how many you can open at any one time.

A quick example: Say you got four people working on their own workstation but you got only two licenses. You can install the software on all four machines but only two people can work with it at any one time. This way nobody has to switch seats when they want to load the RMS for Maya plug-in. Once they finish, the license is released an someone else can work with it. At night, you can also use the free licenses for the render farm.

For this system to work you need to run the license server software. This can be on your workstation or another machine like a fileserver or render farm manager. If you have only one machine on which you use PRMan then it is ok to put the license server software on that specific machine. But when you have more it is better to install it on a dedicated machine that stays on all the time. This doesn't have to be a power house computer. I run mine on a Intel Atom server with 4 GB of RAM running Ubuntu 12.04.4LT which is also my personal web and fileserver.

Installing the license server on Ubuntu

Pixar provides license server software for Windows, Mac OS X and Linux. The linux versions are packaged as rpm. Since Ubuntu does not use rpm packages to install software it seems like Ubuntu is a dead end. But no worries, there is a way to get it all working.

First download the required software from the RenderMan website. I used the RH5 64 bit version which needs at least gcc 4.1. You need to convert this downloaded rpm package to a file type which Ubuntu can read. For this there is a tool called Alien.

To install Alien:

# sudo apt-get install alien

To convert the rpm to deb:

# alien NameOfThePackage.rpm

You should get similar named deb package when the program has finished running. The next step is to install the deb package which can be done with the following command:

# sudo dpkg -i NameOfThePackage.deb

Several files will be installed in /opt/pixar/PixarLicense-versionNumber/

So far, so good. The software is installed but it can't run yet as you need a license file. The documentation states that a program named LicenseApp will be invoked during installation of the license server but this seems only to be working on Windows and Mac OS X and not on Linux. This LicenseApp is used to get a license from Pixar automatically. Since the program does not get installed how is it possible to get a valid license?

You need to go to https://renderman.pixar.com/forum/entitlement.php. Follow the steps on this page and it will generate you a pixar.license file for you. You might need to use pixarhostid which can also be downloaded from the Pixar website. Put the downloaded pixar.license file in the directory above.

The next thing to be done is to start the license server with 

# sudo startPixarLicenseServer.sh

Et voila, your license server is up and running. If you want to make sure if it works, use a web browser to go to http://yourServerName:9010. If it displays your licenses then you're almost good to go.

The last thing you need to do is to put the pixar.license file in the root pixar installation directory of all of your client machines. This way PRMan knows where your server lives.

So where can I buy a license (or a bunch of them)?

If you live in Belgium or the Netherlands then you are in luck. You can contact me and I'll help you get one. You can do this trough Twitter or visit www.refractor.be. Feel free to ask questions too.

If you live elsewhere in the world, simply contact rendermansales@pixar.com

RenderMan Studio 4 and RenderMan Pro Server 17

Last week Pixar released their latest instalment of RenderMan Studio and RenderMan Pro Server. This is quite exciting news so a good reason to write something about it.

Versions and Pricing for RenderMan Studio 4

Pixar used to have two product lines. The cheaper RenderMan for Maya which was a limited plug-in but with an embedded render license and the more expensive RenderMan Studio which had all the regular tools like Slim and "it" but needed a RenderMan Pro Server license to actualy render anything at all. Pixar has consolidated their two Maya plug-ins into one and has adjusted the pricing and functionality. The RenderMan for Maya product line no longers exists and only RenderMan Studio is now available. RenderMan Studio still has all functionalities but Pixar added an embedded render license. In combination with the price drop to $1300 a license this will give bigger companies a considerable expense cut and gives smaller companies the full set of tools for only $300 more than the old RenderMan for Maya license.

This new pricing gives smaller studios the opportunity to start building their RenderMan pipeline without the huge investment that it used to be.

New Features in RenderMan Studio 4

RMS 4 contains the following applications.

• RenderMan for Maya 5
• Slim 10
• "it" 10
• Pixar's RenderMan 17 (embedded version)
• LocalQueue
• Tractor 1.6

The two new applications are the embedded RenderMan 17 and LocalQueue. This last one is particularly handy for artists who like to render locally controlled by a render manager without having to set up an entire render management infrastructure. The embedded renderer is exactly the same as the Pro Server version so there is no difference if you render it locally or on the render farm.

There is a long list of improvements and efficiency updates but one of the more interesting features is "Phisically Plausible Shading". This is a new easy to use advanced shading and lighting workflow which creates very realistic results. Keep in mind that this new workflow is not compatible with the older RMS 3 workflow although the old workflow is still available if you wish to use it. You have to choose which workflow you like to use at the start of your project and stick with it.

Some interesting features of the new RMS 4 plausible shading workflow.

• Raytraced and point-based global illumination: This is controlled with special global GI lights. It supports light linking so it is possible to use pre-computed point clouds for a set while rendering the hero objects with raytraced global illumination.
• Image based lighting is now de-coupled from global illumination. The new RMSEnvLight is a bit slower to calculate but the quality has improved a lot.
• New Area Lights: Area lights are quite hot nowadays. They provide realistic lighting and soft shadows.
• Light Blockers: Although I used this feature many years ago as a custom light shader they have now included this as a standard. This is incredibly handy to subtract light in certain areas of your scene.
• Subsurface scattering trough raytracing: No need to compute pre-passes anymore. This can be handy for relighting purposes as pre-passes can take up too much time.

To facilitate these features Pixar has added new shading nodes which are directly accessible in Maya or trough Slim. The general purpose surface shader supports layering which in my opinion is a very important feature.

New features in RenderMan Pro Server 17

RPS 17 is mainly a speed and efficiency update. I'll mention the features which I think are the more important ones. Hair and fur render up to five times faster and the new implementation of RSL has a 20% speed increase on average on shading calculations. There is also a volume rendering optimization and a new implementation of objects instancing.

Also new: RenderMan On Demand

Pixar also created a new online service called RenderMan On Demand. Whenever you have not enough render capacity it is possible to send your scenes to Pixar and let them render out your scenes. The service fee starts at 70 cent per core per hour.

Links:

Pixar RenderMan website

RenderMan Basics

I recently put my old graduation animation online (which you can watch on youtube: A Plug's Life). It was made back in 2001 and it was my first big project working with Maya and Pixar's RenderMan.

The other day I was asked in the video comments if I could write some tutorials on the use of RenderMan. That sounds like a great idea but before I want to come up with some hands on tutorials it is important to learn something about the RenderMan architecture.

I often hear that RenderMan is not suitable for small studios as it is too complex and is for tech heads and not artists. I beg to differ. RenderMan is a very efficient render engine and small studios which do not have a lot of render capacity can really benefit here by lowering render times. The shading tools are quite extensive and can give superb results without the need of any programming.

What is RenderMan?

First I like to define RenderMan. RenderMan is actually an API (application programming interface) and not a render engine. For a long time Pixar was the only one having RenderMan compliant renderer (as they invented the standard) called Photorealistic RenderMan or in short PRMan. People quickly started to call it RenderMan though and it has stuck ever since. Today there are more commercial render engines available which are RenderMan compliant like 3Delight.

Since Pixar's RenderMan is the industry standard (they say so themselves and honestly it is true), I will use their software to explain my examples.

RIB or RenderMan Interface Bytestream

Since PRMan is a renderer and Maya an animation package, there is need of a common language between the two. The API mentioned before is this language. Have a look at the following schematic.

The scene translator converts Maya data into a RIB file which the render engine understands.

The scene information from Maya is translated into a RIB file. This RIB file contains everything from geometry and information on which shaders are used to render resolution and certain render settings like shading rate. Since a RIB file is written in the common RenderMan language every RenderMan compliant renderer can interpret it and render it.

The RIB file can be displayed as an ASCII file, looks a bit like a programming language and is actually quite readable. We often opened up the RIB file to see where things went wrong when the renderer didn't give us the expected results.

In larger studios this RIB file is usually hacked to add in extra elements before the the final render is made.

RSL or RenderMan Shading Language

Shaders are render engine dependent. This means that when you go from one render engine to another you need to redo the shading. To tackle this problem between RenderMan compliant renderers, the standard provides a common shading language called RenderMan Shading Language. This is a simplified programming language to code shaders. These shaders are then compiled and used by the render engine.

Coding shaders is not what most artists want to do but since RenderMan Studio has a visual tool to create shaders called Slim, artists don't have to feel left behind. Understanding how to code shaders can give you a better insight in how shading works in CGI though.

RenderMan Studio

Pixar's RenderMan is available as a package called RenderMan Studio. It contains:

• RenderMan for Maya (Pro)
• Slim
• it
• Tractor

RenderMan for Maya is the core plug-in. It deals with the scene settings and takes care of translating the scene information into a RIB file. It comes with its own Maya menu and custom shelf.

Slim is the shading management tool. It is an external running program but can be connected to your Maya scene. Custom shading networks can be generated visually as well as trough coding in RSL.

"It" is the image tool. When rendering out your images you can do so to the Maya renderview but also to "it". "It" is much more flexible and allows even simple compositing trough scripting. It also allows the use of Look Up Tables and displays actual pixel values, something the Maya renderview is lacking.

Tractor is the render farm tool which queues and manages your renders. Not only can you manage your RenderMan renders but also other jobs like Nuke composites which you want to be calculated on the render farm.

RenderMan Studio comes with an embedded render license so even small VFX studios can get started straight away.

Links:

Pixar RenderMan website

Refractor: Belgian reseller for Pixar's RenderMan products 

The basics on lighting and rendering 

Render Farms

Projects range from small one person achievements to huge VFX productions where hundreds of artists contribute to the result. The thing they have in common is that they need computational power to finish certain steps in the process. Rendering is the first one that comes to mind but simulations and compositing take up their own share of CPU cycles.

It is possible to let your workstation chug away on those calculations and eventually it will get done but more often than not a tight deadline does nog give you this luxury.

The speed increase with a Render Farm

Render farms are all about speeding things up. Let's say you have only one workstation and you work 8 hours a day (Ok, you have to be lucky to work only 8 hour days in VFX, usually you need to do more to reach the deadline). That means that you have 16 hours left for rendering your sequence. Even with 10 minutes a frame, which is quite acceptable, it will give you 96 frames which is only 4 seconds of animation (at 24 fps that is) a day. You could try to simplify the scene to speed things up but that is not always possible.

The simplest form of a farm is to have second machine next to your workstation which can do calculations while you continue working. This will more than double your capacity and will get you 10 seconds of animation done per day for the same scene. When you have only one machine it is easy enough to manage the rendering of different scene files manually. No extra management software is needed at this point.

Let's move to a bigger setup where there are 5 artists in the shop and let's say they have a workstation each. With the same 10 minute a frame setup it means that they can render 20 seconds of animation each day when working 8 hour days. You can see that the math behind it is simple enough to make predictions once you got an idea how long a frame will take. I must agree that it can be tricky to predict render times when the contents of the scene and hence the render times per frame change a lot. But of course, an indication is better than nothing.

It becomes obvious: the more machines you get, the more complicated the managing of the jobs will become. In these circumstances it is wise to introduce a render manager into the pipeline.

The render manager

The render manager is a piece of software which automates the distribution of jobs to your render farm. It consists out of two parts. The server side program which is the actual manager and the client side program which activates the right renderer for the job. The server side program usually runs on a dedicated machine, very often the same machine as the license server for your software. The client program is installed on each machine which can handle a render job.

Instead of launching the job manually on the client machines it will be submitted to the render manager. When a job is accepted, the render manager has several tasks to do. First it checks the availability of the clients. It then will send a chunk of the job towards a client. The chunk size can be dictated by the user. It can go from part of a frame to a full frame to even a group of frames. If your frames render fast then it is usually better the group them otherwise one frame per client will do fine.

The render manager will now divide all the chunks between the clients. When a client is finished it will report back to the manager and a new job will be given automatically.

Another task of the render manager is to queue the jobs from the users. It allows several people to submit jobs without the fear that they will fail because the render farm might be too busy. The render managers usually have the option to prioritize jobs according to preset rules.

A good render manager will tell you when things go wrong. When a render fails it usually generates an error message which is passed on to the manager. It will then show you which jobs didn't render properly.

What is needed for running a render farm

• Computers: Ok, that is pretty obvious. Fast CPUs and a lot of memory are preferred. You do not want them to start swapping memory to disk. It will grind the render to a halt. Big hard drives are not important, do get server grade ones though. Rack machines are the preferred choice when not using workstations. They are space efficient and are usually server grade so they are made to run 24/7 at full capacity. Do not use the render manager server as a render box so you need one machine dedicated for the manager to run on.
• Operating system: A good rendering manager works cross platform. It doesn't matter if Maya was installed under Windows, MacOSX or Linux. Most render farms run Linux as you can install it without a GUI. This saves memory and makes the machine more efficient (oh, and Linux is free!). Some software packages do not have a Linux or Mac version and then the choice of OS becomes obvious.
• A render manager: If you are serious about rendering you need a render manager. It will automate everything, speed things up and take a lot of worry out of your hands. It will also make your farm very scalable. There are many different ones out there and all come at different prices so it is hard to recommend any of them.
• Software Licenses: That's right, software is usually not free and you need to buy the right amount of licenses. Most VFX packages have separate render licenses. They tend to be cheaper and are sometimes sold in bundles. For example Maya comes with 5 render licenses when you buy a floating license. Take note that you can only use packages which have a command line render options. A render manager can not start GUIs.
• Network: A fast network is a must. The bigger your farm becomes the more data you have to pull trough those wires. Yes, wires. Running a farm on WiFi is a bad idea.
• A storage server: Rendering images or baking out data can fill up disks pretty quick. A good server with a RAID system for redundancy and continuity will be ideal for storing data. You do not want to loose all that render time because a disk went bad. Remember: a RAID is not a backup system, it was designed to let you keep on working even when a disk dies on you. If you want to be sure that your render data is safe, copy it to a second server after the render job finishes.

Scalability

One of the things we notice in VFX is that render and simulation times never seem to go down. We would assume that with faster processors our render times would go down but instead we see another evolution where the render times stay the same but the complexity of the scene goes up. 

Lucky for us, render farms are to a point very scalable. Just add in more machines and licenses when needed. It only becomes a problem when the server or the network can not handle the traffic anymore. You can imagine that a farm at ILM or Pixar is a complex matter to maintain.

If you you need a quick boost in render capacity but don't have the cash to expand the farm,  you can always hire the services of online render farms. You could say that it is rendering in the cloud. It works very similar as your local render farm with the main difference that you need to upload your data to the cloud first. With a slow internet connection this may take a while but once in the cloud the renders go really fast.