Using multiple projectors

Lightform Creator and Lightform devices currently do not directly support creating experiences with more than one device/projector. However, through a couple of tricks, you can create a multi-projector experience with no additional tools.

multipleProjectors-cover.gif

  1. Blending three LF2s to turn a room into an IMAX
  2. Stacking three projectors for extra brightness

In general, multi-projector setups typically require the following:

  • Content Alignment - Aligning the content across all projectors
  • Edge blending - Blending the regions in which the projectors overlap
  • Playback Synchronization - Ensuring your content plays back synchronized

In this article, we'll show you how to achieve these in Lightform Creator.

Please Note
Depending on the scenario, Creator may not be the best tool for your multi-projector setup. There are enterprise solutions, such as VIOSO (among many others), that have special-purpose tools for multi-projector setups.


Blending three LF2s to turn a room into an IMAX

In this example, we've set up three LF2s stretched across three walls of a room:

multipleProjectors1_1x.png

We will show how to align and blend the content to stretch across all three projectors. For example:

multipleProjectors_LF2s.gif

  1. Setup your projectors: It's essential to make sure your projectors have enough overlap to be blended correctly and that they are in the desired orientation.
  2. [Optional] Open multiple instances of Lightform Creator (only possible on macOS), one for every projector in use. It is possible to complete this example using just a single instance of Creator, but having the ability to work on all projects simultaneously without switching between devices will speed up the workflow.
  3. Content Alignment: Align content using a test pattern that is the same size as the video/content you will be projecting. 

    Please Note
    There are many ways to align content. We outline one way that works well with Lightform Creator. If you already have experience with this, feel free to use the workflow that you already know.

    • First, choose the content you want to stretch across the projectors. In this example, we are using three 1080p projectors horizontally (almost 3x1080=5760 pixels wide), so the higher the resolution, the better.
    • Then, download a test pattern from Thomas Schmall. This website provides test patterns of size 4096x4096, 4096x2048, and 2048x4096. Choose the one that is the closest to your source input content. For example, if the content you want to project is 1080p (1920x1080), crop or resize one of these patterns to 1920x1080. Just about any test pattern will do if you already have a favorite, including this generator from VIOSO in which you can specify the exact size.
    • For each projector, starting from the middle and then moving outward:
      • Create a new project
      • Take a scan
      • Import the test pattern from the previous step and insert it into a Surface in your project
    • Using the Edit tools in Creator (scale, move, corner pin), adjust the test pattern in all three projects to align it across the projectors, especially in the projection's overlapping portions. This the most tedious and time-consuming step in this example and requires some amount of trial and error. Depending on the content and how important alignment is, you can spend more or less time perfecting the alignment. Some tips:
      • If you are using multiple Creator instances, you can utilize the Preview functionality to see and adjust the alignment in real time, swapping back and forth between each projector until finished.
    • Otherwise, if you are only using a single Creator instance, start with one projector and scale/move the test pattern where you want it, then publish that slide to show it on the projector. Then move to the next projector and use "Preview" to align it to the first projector's test pattern. Publish the result, so it stays visible. Repeat until all projectors are aligned. For this workflow, it is best to work from the middle projector and move outward.
  4. Projector Edge Blending: Blend the overlapping regions of the projectors to hide the overlap seams.
    • To blend content at the seams, we will use the "Gradient" effect where the gradient values go from rgba=(0,0,0,0) (transparent black) to rgba=(0,0,0,255) (opaque black).
    • Using a similar trial-and-error workflow as the previous step, add Gradient effects and position them to "fade out" the content at the seams. Here's an example from the middle projector of this example. Note the "Color Begin / End" settings, and that there are two gradients used (one on each side) since the middle projector in this example has seams on both sides.
      multipleProjectors_LF2s.png
  5. Add content to the projects
    • Next, add the content to the projects, and add the videos to the necessary slides.
    • Because we made the test pattern to be the same size as the content, we can copy/paste each item of the "Transform" panel from the test pattern to the content, and it will have the same alignment as the test pattern that you put so much time into aligning!
      multipleProjectors_LF2s2.png
  6. Publish: Once everything is set, publish the content on all projects/projectors.

    Please Note
    The slide durations and the number of slides should be exactly the same in each project.

  7. Synchronization: After publishing, the devices will all be playing back content at different times. You can use OSC broadcasting to synchronize the playback across all projectors.

Final Result

Timelapse of the entire 30 minute process

All projects used to make the example above:

👉 Multiple Projector projects


Stacking three projectors for extra brightness

In this example, we will point multiple projectors at the same object to achieve a brighter image. Stacking projectors is typically done as a cost-saving measure as multiple lower-lumen projectors are often significantly cheaper than buying a single high-lumen projector.

This example's workflow is much like in example 1 but less complex since the scans from each projector can be used for alignment, rather than using a test pattern for alignment and performing blending.

stack-1.gif

One Projector

stack-2.gif

Two Projectors

stack-3.gif

Three Projectors

  1. Set up your projectors in the proper orientation, pointing at the scene you want to project on and with as much overlap as possible.
  2. For the first projector, scan your scene and create content as you usually would. Publish the result to the projector, then stop the playback so you can scan and work on the next projector.
  3. Duplicate this project (File→Save and Increment Project) and then open the duplicated project. Now take a scan with the second projector and manually move the content into place to align with this second projector's perspective. For effects that use the scan image, this amounts to merely moving the surfaces to the right spot. You should take more care for videos or generators to ensure the content is aligned (use the test pattern from the previous example, if needed). Publish the result.
  4. Repeat the previous step for as many projectors as you have.
  5. Finally, use OSC broadcasting to synchronize the playback across all projectors.
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