The image above shows a possible nDisplay network. Like all nDisplay networks, one of its PCs acts as the master node. This master node accepts input into the system from a VRPN server, which relays signals that come from spatial tracking devices and other controller devices. The network also contains several other PCs that run other instances of the Unreal Engine Project. Each of these cluster nodes drives one or more display projectorsof these cluster nodes drives one or more display projectors.

Why Use nDisplay over the Unreal Toolkit Plugin

There are some inherent problems with the Unreal toolkit that are difficult to overcome. These include:

Slow performance with large complex, or optimized models.
No-post processing available
Issues with Lumen lighting engine not rendering correctly
Miss matched colours compared to the console view.
Limited to cubemap output, that only works in ICE.

nDisplay removes all of these issues, and adds even more features which include:

Clustering for complex and highly detailed models.
Large scale resolutions
True to life colours
Optitrack and VRPN support
Doesn’t require an external plugin
Doesn’t require an update from Igloo every time there’s a new Unreal update.

Warning
The only current issue with nDisplay is the lack of a method to input warps generated by the Igloo system. Requiring the use of scalable to do curved screens at this stage.

PC Specification for Igloo

The main machine will be the same as the ICE machine. It should be high specification as it will be the center for the models, as the master node. However it will only need to output a single display, and not output anything to the projectors (only the console monitor)

However, it will be responsible for starting Unreal and telling all the other PC’s what to do, as it will be the Master node on the above diagram.

The individual machines will be infrequently used, and will need to be ‘gamer’ ready. This is due to Unreal not outputting it’s best when using Quadro based graphics cards. It also means they can be off the shelf cheaper products with a decent warranty. They can also be specified as smaller form factor machines to fit nicely into a server rack.

A company called MK1 Manufacturing make a wide range of lenovo rack mounting solutions, and could be commissioned to make one for their gaming machine chassis.

Possible solutions could include the LOQ machine, and the Legion T5 machine.

Info
Further conversations need to happen with Bill to recommend something suitable for a cluster solution.

Setting up nDisplay within Unreal

Prerequisites

Unreal Version 22 4.4 or newer.A computer with more than 1 screen, in an extended configuration.
The computer should be capable of running Unreal Engine, based on these recommended specifications.

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Info
It’s a good idea to create the project within a location that is easy to share on a network. This makes it a lot easier to create the cluster further into the nDisplay pipeline.

Existing Project

Open your project, and navigate to the Plugin’s window. Search for nDisplay and Enable the nDisplay plugin. This plugin is included in Unreal 2.46 and newer.
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Info
You will be asked to restart your editor upon selection. I would recommend saving your work and doing this straight away. Grab a coffee, and wait for it to recompile.

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Info
The computer you are using to calibrate the display is automatically assigned to the system with the name LocalHost. If the Calibration PC will not be driving a display, remove LocalHost from the Display clients assigned to the system list.

Click to highlight one of the clients in your system.
Click Assign > to move the clients into the system.
Repeat for all remaining clients.

Scalable Display Manager will by default output a scalable mesh file, if instead you would like to directly apply the warp and blend in the graphics driver check the option Apply Warp & Blend in Graphics Driver.

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Note

Wrong Number of Projectors or Incorrect Resolution

If the number of projectors or their resolution is different from the actual system, manually choose or enter the resolution of a single projector under custom resolution.

Click resolution per projector drop down.
Select the Width and Height to the resolution of a single projector in pixels (e.g. 1920 x 1080)
1. OR Select Custom.
2. Set the Width and Height to the resolution of a single projector in pixels.
3. Click OK
Click Redetect Displays.

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To help with making sure that the projectors reach about an overlap value of 15-20% you can click Show Overlap Pattern. There are 3 sections Yellow,Green, and White. Having the edges of the bands touch will result in the level of overlap it represents.

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Enter the Projector Arrangement

Select the physical arrangement of the projectors: Tiled, if the projectors are next to each other, or Stacked, if the projectors are on top of each other.
Select the number of projectors in a row.
Select the number of projectors in a column.
Click Redetect Displays to save the settings.

Order the Display Clients

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Next, two images will be displayed on each projector, starting again with the first projector and going in order to the last. The first image will be a 5-dot pattern which is used to determine the center of the projected image. The second image displayed is the grid pattern which is used to map where the pixels are falling on the screen.

White Pattern	5 Dot Pattern	Grid Pattern
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What to do if an Error Occurs

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The software can not discern the difference between a projected image that does not fill the screen and one that fills the screen but spills off.

End Calibration: In this case, the calibration should be stopped so that the camera can be re-positioned to see the entire projected image.	Image Modified
Ignore and Continue: The error action is expected and triggered because the projector is overshooting the screen. Continuing will not cause any issues.	Image Modified

Choice	Description
Remember this action for this projector for session	Do not stop the calibration for this error on this projector until the software is restarted
Remember this action for this projector forever	Never stop the calibration for this error on this projector
Remember this action for all projectors for session	Do not stop the calibration for this error on any projector until the software is restarted
Remember this action for all projectors forever	Never stop the calibration for this error on any projector

Projector Visibility

Be careful when editing

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Essentially that is all that’s required , but we will need to calibrate the eye location later on when setting up Unreal correctly for head trackingfor standard nDisplay, from Scalable’s perspective.
However, if you’re using head tracking, it is required that you adjust the eye level to the correct height, for where the exact center of the room will be.

Exporting Data to Unreal

Once your screen has been calibrated using the Scalable system, the master machine will have saved the DataSet to it’s C:/ drive, in the following folder:

Code Block
C:/ScalableDisplay/DataSets/DatasetXXXXXXXXXX/LastCalibration:\Program Files\Scalable Display\DEI\LocalCalibration

In this folder, you will find a myriad of files, most of which are required for the nDisplay system to work.
Unfortunately, due to how these files are created, it’s difficult to setup this location as a shared space, so you will need to copy these files *(or rather the LastCalibration Folder as a whole) to the same location as your nDisplay config file.

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a location similar to where your config.

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Warning
Just like all other file locations, there can be no spaces in the address. Otherwise it won’t launch.

Not all the files are required, but it’s easier to copy the entire thing.

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Expand

title	Example config file

You are welcome to copy this file, and expand on it. You should save it as a .cfg.
It’s a 3 Igloo Media Server (IMP) 3 Projector system.

Code Block
# Tracker [input] id="ViveVRPN" type="tracker" addr="openvr/controller/LHR-8708C47F@10.1.5.169:3884" loc="X=0,Y=0,Z=0" rot="P=0,Y=0,R=0" front="Y" right="-X" up="Z"

Code Block

#####################################################################
# Igloo nDisplay Example Configuarion
#
# Note:
# Before use, make sure all settings correspond to your system.
#####################################################################

# Config file header.
[info] version="23"

# Cluster nodes
[cluster_node] id="IMP1" addr="19210.1681.05.101110" window="window1" master="true"
[cluster_node] id="IMP2" addr="19210.1681.05.102247" window="window2"
[cluster_node] id="IMP3" addr="19210.1681.0.1035.169" window="window3" windowmaster="window3true"

# Application windows
[window] id="window1" fullscreen=false WinX=0 WinY=0 ResX=1920 ResY=1080true viewports="viewport1"
[window] id="window2" fullscreen=false WinX=0 WinY=0 ResX=1920 ResY=1080true viewports="viewport2"
[window] id="window3" fullscreen=false WinX=01920 WinY=0 ResX=1920 ResY=1080 viewports="viewport3"

# Projection policies
[projection] id=projector1proj_easyblend_1 type="easyblend" file="LastCalibration\ScalableDataOrthographicD:\LocalCalibration\ScalableData.pol"   origin=easyblend_origin scale=1
[projection] id=projector2proj_easyblend_2 type="easyblend" file="LastCalibration\ScalableDataOrthographicD:\LocalCalibration\ScalableData.pol_1" origin=easyblend_origin scale=1
[projection] id=projector3proj_easyblend_3 type="easyblend" file="LastCalibration\ScalableDataOrthographicD:\LocalCalibration\ScalableData.pol_2" origin=easyblend_origin scale=1

# Viewports
[viewport] id="viewport1" x=0 y=0 width=1920 height=1080 projection=projector1proj_easyblend_1
[viewport] id="viewport2" x=0 y=0 width=1920 height=1080 projection=projector2proj_easyblend_2
[viewport] id="viewport3" x=0 y=0 width=1920 height=1080 projection=projector3proj_easyblend_3

# Cameras
[camera] id=camera_static loc="X=0,Y=0,Z=0" tracker_id="ViveVRPN" tracker_ch=0

# Scene nodes
[scene_node] id=cave_origin       loc="X=0,Y=0,Z=0" rot="P=0,Y=0,R=0"
[scene_node] id=wand              loc="X=0,Y=0,Z=1" rot="P=0,Y=0,R=0"
[scene_node] id=easyblend_origin  loc="X=0,Y=0,Z=0" rot="P=0,Y=0,R=0"

# Tracker
[input] id="ViveVRPN" type="tracker"  addr="openvr/controller/LHR-8708C47F@10.1.5.169:3884" loc="X=0,Y=0,Z=0" rot="P=0,Y=0,R=0" front="Y" right="-X" up="Z"

# General settings
[general] swap_sync_policy=1

# Network settings
[network] cln_conn_tries_amount=10 cln_conn_retry_delay=1000 game_start_timeout=30000 barrier_wait_timeout=5000

# Custom arguments
[custom] SampleArg1=SampleVal1 SampleArg2=SampleVal2

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The projection value, explained below, is which projection policy will be used

Projection

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`[projection] id=proj_easyblend_1 type="easyblend" file="`
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`D:\LocalCalibration\ScalableData.pol" origin=easyblend_`
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`origin scale=`
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`1`
This is where the scalable setup differs from a standard nDisplay system. Instead of a ‘simple’ projection system, which specifies the cameras created by unreal, we use Scalable & Unreal’s easyblend system. This tells unreal how to create cameras based on the .pol data created by Scalable during setup.
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The field value should be the location of your ScalabaleData.pol file relative to the location of this file. It’s also possible to put a complete file address , but this may cause issues as it will likely be stored on a shared drivelike within the example, but be careful to have the same address across all machines.
Info
If you are using one machine, with multiple screens, each screen will have it’s own .pol file.

Camera

[camera] id=camera_static loc="X=0,Y=0,Z=0" tracker_id="ViveVRPN" tracker_ch=0

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The example above, uses a HTC Vive, with a Vive tracker puck. Which also requires you to run an OpenVRPN server to convert the vive position data to something readable by other programs, and then hosts it on the network.

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Expand

title	Creating a shared drive (Windows 10)

Make sure that all computers on the network can see each other. This is possible in the network rollout within the explorer window. As long as all machines are visible, they should have access to the shared drive.
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If you cannot see any other computers in this window, you will need to Enable network discovery. This can be done by doing the following:
- Open Start
- Type ‘Control Panel’
- Click Control Panel
- Click Network and Sharing Center (you may need to click the Network and Internet heading
- Click Change Advance sharing settings in the upper left side.
- Check “Turn on network Discovery”
- Check “Turn on file and printer sharing”
- Click Save Changes and continue.

You will need to repeat this process on every machine in the cluster, so they can all see and talk to each other.
On the Master machine, locate the folder you wish to share with all the other machines. The items you will need to share are:
- The Unreal build in it’s entirety
- The Unreal nDisplay config file
- The Scalable data (should be near the config file)
- The nDisplay Listener.exe (and it’s config files)

I created a folder in my D drive called ‘nDisplayBuild’ and placed everything in that folder, like so.
Test1, and Test2 are the names of my Unreal Builds
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Right click the folder you would like to share, and click Properties and click on the Sharing tab.
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Click Share…
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Your name will be in the list, but you need to add Everyone if it’s not already present. Then add a Read/Write permission level (Read would be fine, but it stops the ability to write Log files)

Click the Share button, and accept the warning that pops up. The folder will now be shared across all the machines. Provided the have access credentials to the master machine. This is usually just the username and password you use to log into it.
The next step is to add the shared folder we just created as a drive with the same location on all the machines. The first step is to identify a drive letter that is not present on all the machines. E is usually free, as most modern machines will have two drives. C and D however, if that is not present pick one further up the alphabet. It has to be the same location on all machines.

When ready, on each machine (including the master) Open the explorer window, and Right Click This PC, then select Map Network Drive
This window will pop up.
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Pick your drive letter, and then click browse to bring up the Browse for Folder window, select the root folder that you created earlier, and click OK

You also have the option to connect at Sign-in, and connect using different credentials. Both of which are extremely important for all the machines (except credentials for the master, as they will be the same). These settings allow for autonomous restarting of the machines without issues.

Once done, click Finish and you will have a network drive underneath your local drives on the This PC menu. It will have a drive letter, and provide a universal location for all machines to access the same files, at the same exact file path when added to all of them.
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This is a very common process, and if you run into any issues, there is lots of support online by searching for ‘Windows 10 add shared drive’

It is advised that all of these methods have their drawbacks, and only the config file doesn’t have any issues being accessed from multiple places.

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The Launcher looks like this, with 3 main fields:

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Add your packaged Project .exe file to the Applications list.
Click Add under the Applications list, then browse to and select the .exe file you packaged for your Project. The nDisplay Launcher will add your new application to the list. Click its name to select it. This must be the same location on all the machines in the cluster. The addresses must match.
Specify your configuration file. Again, this must be a shared location, with the same address for all machines.
Make sure your application is highlighted, it will say ‘no application is selected’ otherwise. Then click Run

As long as your configuration is correct, you will see it send a run command to all the PC’s on the network.

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Version	Old Version 9	New Version Current
Changes made by	Lawrence Selly (Unlicensed)	Lawrence Selly
Saved on	Jan 15, 2021	Jul 28, 2023

Versions Compared

Key

Why Use nDisplay over the Unreal Toolkit Plugin

PC Specification for Igloo

Setting up nDisplay within Unreal

Prerequisites