Mastering LW ScreamerNet

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ScreamerNet lwsn is a Unix executable that runs in the Mac OS X Terminal. You can use a variety of command line parameters to manually configure and launch lwsn in Terminal. We’ve also created an Aqua GUI front end named DLI_SNUB-Launcher™ that you can use to interactively build command lines in a Mac friendly error-free manner that is drag-and-drop-dead-easy™.

• Interactively Building ScreamerNet UB Command Lines with DreamLight SNUB-Launcher
• General Command Line Syntax
• Hub Switch
• Command Line Path Parameters
• -c Config Directory
• -p Plugin Config Dir
• General ScreamerNet Command Line Syntax
• Rendering Mode
• -c Config Directory
• -d Content Directory
• -l Log File
• -q Quiet Mode
• -t Time Check Interval
• Standalone Mode (-3) Command Line Syntax
• Scene File
• Frames to Render
• Batch/Network Mode (-2) Command Line Syntax
• Job File
• Ack File

Interactively Building ScreamerNet UB Command Lines with DreamLight SNUB-Launcher

While you can of course type your ScreamerNet lwsn command lines in Terminal manually, it can become quite error prone and tedious, especially if you change your content directory or other settings regularly. To avoid such issues we wrote a neat little utility, DLI_SNUB-Launcher™ (DreamLight Interactive’s ScreamerNet Universal Binary Launcher) in Apple’s Xcode to provide an Aqua GUI to take the drudgery out of it and to prevent syntax errors which can make setting up ScreamerNet lwsn more difficult than it really needs to be. Using its simple drag-and-drop interface you can quickly and easily set up complicated lwsn command lines that are validated and ready to go, then with a single button you can launch multiple ScreamerNet lwsn nodes for rendering. It’s also a standalone render droplet meaning you can simply drop scenes on it and it’ll launch ScreamerNet lwsn and render them for you.

Even if you prefer to use Terminal to launch lwsn manually you can still use DLI_SNUB-Launcher to build and verify your command lines and then copy/paste them into Terminal to execute them. It’s also a very handy reference resource since every setting has detailed pop-up descriptions and the help menu links directly to the online manual and even includes direct links to all the content in this Mastering LightWave ScreamerNet for Mac OS X white paper. And as an added bonus we’ve even included a custom professionally designed sample scene, DLI_SuperBalls, with a content folder that you can use to test your ScreamerNet lwsn setup, benchmark the speed of your Macs and even use as a sample of advanced nodal surfacing and LW11’s new built-in instancing.

The FREE Lite version of DLI_SNUB-Launcher is fully functional and only limited by the number of nodes it can launch and which custom settings it will save.

DreamLight Interactive ScreamerNet UB Launcher Update

DLI_SNUB-Launcher™ is an XCode Aqua GUI front end to interactively configure and launch LightWave 9, 10 & 11+ ScreamerNet UB lwsn instances for standalone, batch and network rendering. Download your copy today!

Created by the author of Creating a 3D Animated CGI Short
& Mastering LightWave ScreamerNet (lwsn) for Mac OS X
Michael Scaramozzino - LightWave 3D Artist Profile.

General Command Line Syntax

LightWave 3D’s general command line syntax is as follows, all on one line with a space separating each parameter. Do not separate a parameter from its value with a space. All parameter letters must be in lowercase. Enclose all paths with double quotes, especially if the path contains spaces. This syntax is used in the Mac OS X terminal command line when launching ScreamerNet lwsn.

[-0] [-c<config directory>] [-p<plugin config dir>]

The following general command line parameters may be used when launching most of the LightWave applications from the command line, including ScreamerNet lwsn.

Hub Switch

-0: (dash zero) Optional: Disables the Hub

Though not used with ScreamerNet lwsn, this parameter was previously used when launching LightWave Layout and/or Modeler to disable the Hub, because the Hub ,was sometimes the source of problems. The easiest way to disable the current Hub on Mac OS X is to simply rename the Hub application to something else, like Disabled-Hub, in which case it will no longer automatically launch with Layout or Modeler.

Command Line Path Parameters

When specifying command line path parameters, the following rules of thumb may be helpful:

• Type the parameter letter, such as -c or -p, in lowercase.
• Use a plain dash before the parameter letter.
• Do not put a space between the parameter letter and the associated path.
• Enclose all paths in double quotes (straight double quotes, not curly quotes) if the path contains any spaces or you must escape any special characters. I find it easiest to just be consistent and simply enclose all paths in double quotes. Only enclose the path, not the leading parameter.
• Avoid using spaces in file or folder names inside the content directory, use underscore.
• For paths on volumes other than the system volume, start the paths with "/Volumes/volumename/" replacing volumename with the actual volume name.
• For paths in the current user’s home folder, start the paths with
  "/Users/username/" replacing username with the current user name.
• Use full paths for your ScreamerNet lwsn paths because content directory relative paths may not work properly in ScreamerNet UB on Mac OS X.
• Beginning with Mac OS X 10.7 Lion, the user’s Library folder is hidden, so you need to use the Finder’s Go->Go to Folder... menu command with ~/Library in the text field to view any of the current user’s Library folders from within the Finder.

-c Config Directory

-c : Optional: Path to the folder that contains the config file.

An example of the parameter with the initially searched Config Directory path is as follows:

-c"/Applications/NewTek/LightWave3D11.0/Preferences"

There are two default Config Directory locations that are checked by LightWave 3D on Mac OS X. The first location looked for is a custom folder that you may have created named Preferences inside the current LightWave3D application folder. So that would be a convenient place to keep your config files if you would like all users of the Mac to share the same config files and/or if you’d like to use different sets of config files for different builds of LightWave.

If no such Preferences folder exists the next default location searched is the current user’s Library/Application Support/NewTek/LightWave/11.0/ folder.

This full path would be as follows:

"/Users/username/Library/Application Support/NewTek/LightWave/11.0"

Where username is replaced with the actual name of the current user and 11.0 is replaced with the version of LightWave being used.

Because this default location is in the current user’s home folder, each different user account on the Mac would have their own set of config files. On Mac OS X 10.7 Lion and later the user’s Library folder is hidden so you need to use the Finder’s Go->Go to Folder... menu command with ~/Library in the text field to access the user’s Library folders from within the Finder.

For more information see: Managing LightWave’s All Important Config Files.

This parameter may be used to specify a different folder location for the config files if desired.

-p Plugin Config Dir

-p : Optional: Path to the folder that contains the plugin database file. This is not the path to the actual plugins themselves. This is the path to the text file that lists all the paths to the actual plugins. This is typically the same path as that of the Config Directory.

An example of this parameter with the initially searched Plugin Config Dir path is as follows:

-c"/Applications/NewTek/LightWave3D11.0/Preferences"

If not specified, the Config Directory path will be used. This parameter may be used to specify a different folder location for the plugin database file if desired.

General ScreamerNet Command Line Syntax

There are a few common command line parameters that are used to tell ScreamerNet lwsn what to do. The following general command line parameters may be used when running ScreamerNet lwsn in any mode. Additional mode specific command line parameters are discussed later.

The general command line syntax is as follows, all on one line.

-<mode#> [-c<config directory>] [-d<content directory>] [-l<log file>] [-q]

Rendering Mode

-<mode#> : The mode number parameter specifies which rendering mode to use.

-2 : Signifies batch or network rendering mode which may render multiple scenes on multiple nodes.

-3 : Signifies standalone rendering mode which renders a single scene on a single node.

-c Config Directory

-c : Optional: Path to the folder that contains the config file.

An example of this parameter with the initially searched Config Directory path is as follows:

-c"/Applications/NewTek/LightWave3D11.0/Preferences"

This parameter is explained in more detail above under Command Line Path Parameters.

-d Content Directory

-d : Optional: Path to the folder that contains your content.

An example of this parameter with a sample Content Directory path could be as follows:

-d"/Users/username/Documents/LWContent"

Where username should be replaced with the current user name. This example would be to use a folder named LWContent in your Documents folder as your content folder. If this option is not specified, the content directory defaults to the content directory specified in the config file through LightWave. Therefore, if you set your content directory in LightWave itself, and you have ScreamerNet lwsn on the same machine using the same config file as LightWave (which it does by default), you do not need to specify this option in the ScreamerNet lwsn terminal command line, unless you wish to use a content directory that is different than the one currently set in LightWave. You would also need to specify this path if you were running ScreamerNet lwsn on a different machine than you are running LightWave.

Please review Config Files: Content Directory, for important information about using LightWave’s Content Directory properly.

-l Log File

-l : Optional: Path to a text file to write the ScreamerNet lwsn output into.

An example of this parameter with a sample Log File path could be as follows:

-l"/Users/username/Documents/LWContent/ScreamerNetLog.txt"

Where username should be replaced with the current user name. This example would use a Log File named ScreamerNetLog.txt in a LWContent folder in the current user’s Documents folder. If this option is not specified then the text messages generated as output would appear in the Mac OS X terminal window that is running ScreamerNet lwsn. The current user must have read/write permissions for this file.

-q Quiet Mode

-q : Optional: Suppresses terminal output during frame rendering, still reports as each frame finishes.

Normally while ScreamerNet lwsn is busy rendering it outputs quite a bit of text information to the terminal interface. This can be useful for monitoring progress and troubleshooting problems such as missing plug-ins, etc. Once everything is up and running however, all this text writing to the terminal may be unnecessary. The -q parameter turns off all the output during the rendering of an individual frame. You’ll still get text output during the scene loading and between rendered frames, but not during frame rendering.

Here’s an example of what the output for one frame normally looks like, without the -q parameter:

Scene loaded.
Allocating frame buffers.
Allocating segment buffers.
Frame: 1.
Segment: 1/1.
Pass: 1/1.
Updating geometry.
Moving DLI_Floor_01F (1).
Moving DLI_SuperBall_01H.
Moving DLI_Floor_01F (2).
Preprocessing Frame....
Computing preliminary radiosity solution....
Rendering frame 1, segment 1/1, pass 1/1.
Image Reconstruction.
Image Reconstruction : 0%.
Image Reconstruction : 4%.
Image Reconstruction : 8%.
Image Reconstruction : 13%.
Image Reconstruction : 17%.
Image Reconstruction : 22%.
Image Reconstruction : 26%.
Image Reconstruction : 31%.
Image Reconstruction : 35%.
Image Reconstruction : 40%.
Image Reconstruction : 44%.
Image Reconstruction : 49%.
Image Reconstruction : 53%.
Image Reconstruction : 58%.
Image Reconstruction : 62%.
Image Reconstruction : 67%.
Image Reconstruction : 71%.
Image Reconstruction : 75%.
Image Reconstruction : 80%.
Image Reconstruction : 84%.
Image Reconstruction : 89%.
Image Reconstruction : 93%.
Image Reconstruction : 98%.
Freeing segment buffers.
Allocating filter buffer.
Freeing filter buffer.
Allocating segment buffers.
Writing RGB image to /Users/user/Documents/DLI_SuperBalls/Renders/DLI_LW11-SuperBalls-Anim_001.jpg.
Frame completed.
Last Frame Rendered: 1.
Rendering Time: 1m 9s (69.3 seconds).
Freeing segment buffers.
Freeing frame buffers.

Here’s what the the same output looks like with the -q parameter included:

Scene loaded.
Last Frame Rendered: 1.

-t Time Check Interval

-t : Optional: Time check interval in seconds.

An example of this parameter with a sample Time Check Interval could be as follows:

-t60

This sample would have ScreamerNet lwsn attempt to check the job file every 60 seconds for status or abort commands when rendering in batch/network mode -2. Other commands in mode -2 are ignored. When rendering in standalone mode-3 ScreamerNet lwsn would report its current status every 60 seconds.

Normally, once ScreamerNet lwsn begins rendering a frame, it does not check the job file for any further instructions until the frame finishes rendering. During the initial setup and testing of your render farm or when testing a new scene, it may be useful to allow ScreamerNet to check the job file for abort or status commands. Particularly if individual frames take a long time to render. This way, if you notice a problem at the beginning of rendering (a missing plug-in for instance), you can abort the rendering without having to wait for all your nodes to finish rendering an entire frame each or force quitting each node.

For instance, if your frames use ray tracing, area lights, radiosity, caustics, high antialiasing levels, motion blur and/or depth of field, they may take a long time to render. In this case you could set -t to 60 seconds, then ScreamerNet would try to check the job file every 60 seconds to see if the job should be aborted or if status information should be written to the output. During certain processing, ScreamerNet may still take longer than 60 seconds before it can check, but it doesn’t have to wait for an entire frame to render before being able to stop or report status. Once you are sure everything is running smoothly, it is best to remove this option, so that no extra time is taken checking the job file or reporting status unnecessarily, especially if you are network rendering many frames.

Standalone Mode (-3) Command Line Syntax

The standalone mode (-3) specific command line syntax is as follows, all on one line.

-3 [-c<config directory>] [-d<content directory>] [-l<log file>] [-q] <scene file> <first frame> <last frame> [<frame step>]

The first five parameters are explained above under General ScreamerNet Command Line Syntax.

Scene File

<scene file>: Full path to the scene file.

A sample of a full scene path could be as follows:

"/Users/username/Documents/DLI_SuperBalls/Scenes/SuperBalls-Anim.lws"

Where username is replaced with the current user name. Be sure to use a full path to the scene file rather than a Content Directory relative path because Content Directory relative paths may not work on some versions of ScreamerNet UB lwsn on the Mac. Also be sure to enclose the entire path in double quotes, especially if it contains spaces or other special characters.

Frames to Render

<first frame>: First frame to render. Normally less than last frame but may be greater than last frame if frame step is negative.

<last frame>: Last frame to render. Normally greater than or equal to first frame but may be less than first frame if frame step is negative.

[<frame step>]: Optional: defaults to 1, may be positive or negative.

Frame step specifies which frames to render between the first and last frame, and in what order. When set to 1, ScreamerNet would render every frame from the first frame, up to the last frame. When set to 2, ScreamerNet would render every other frame from the first frame up to the last frame. If set to -1, ScreamerNet would render every frame from the first frame, down to the last frame and in this case the first frame should be greater than the last frame to render in reverse order.

Batch/Network Mode (-2) Command Line Syntax

The batch & network mode (-2) specific command line syntax is as follows, all on one line.

-2 [-c<config directory>] [-d<content directory>] [-l<log file>] [-q]
[-t<check interval>] <job file> <ack file>

The first five parameters are explained above under General ScreamerNet Command Line Syntax.

Job File

<job file> : job# File path & node number for lwsn to read commands from.

A sample job file path could be as follows:

"/Users/username/Documents/DLI_SuperBalls/Commands/job1"

This example reads the job1 text file in a Commands folder in a DLI_SuperBalls folder in the user’s Documents folder, where username should be replaced with the current user name.

The number should immediately follow the word "job" without any spaces and there must be no file extension, such as ".txt" added to the end of the path.

Make sure that your job# and ack# both use the same number. This number is what actually determines the CPU number of the ScreamerNet node so that the ScreamerNet network controller may communicate with this lwsn render node.

For additional information please review Config Files: Command Directory.

Ack File

<ack file> : ack# (acknowledgment) File path & node number for lwsn to write replies to.

A sample ack file path could be as follows:

"/Users/username/Documents/DLI_SuperBalls/Commands/ack1"

This example writes to the ack1 file in a Commands folder in a DLI_Superballs folder in the user’s Documents folder, where username should be replaced with the current user name. The current user must have read/write permissions for this file.

For additional information please review Job File above & Config Files: Command Directory.

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