Welcome to Stacker’s documentation!


The Stacker App allows you to align projector stacks containing up to 4 projectors using a mobile device.


Requires iOS 13 or later. Compatible with iPhone and iPad.

Supported Projectors

Barco Pulse projectors are supported. A sample of compatible models is provided below, with their native resolutions in brackets. It is important to know the projectors’ native resolution as this is what the resolution must be set to in Stacker. To find out whether your projector is supported, and what its native resolution is, look for it in this list of Pulse products on Barco’s website.

  • Some compatible Barco Pulse Projectors:

    • FS40-4K (2560 x 1600)

    • F70-4K, FS70-4K (2560 x 1600)

    • F80-4K (2716 x 1600)

    • F90-4K (2560 x 1600)

    • UDM-W (1920 x 1200)

    • UDM-4k (2560 x 1600)

    • UDX-W (1920 x 1200)

    • UDX-4k (2560 x 1600)

Quick Start


  1. Connect your device and projector to the same local network

  2. Connect a computer showing the same image on all projectors Unaligned

  3. Roughly overlay your projectors using physical placement, lens shift and zoom Rough Aligned


  1. Open the Stacker App Settings

  2. Set projectors’ native resolution (for information on how to find your projectors’ native resolution please see the Supported Projectors section in the introduction)

  3. Add as many projector slots as required

  4. Search and select projectors for each slot. Alternatively set IP-Address manually Settings

  5. Accept Settings


  1. Point your camera at the projected image (use a tripod if multi-shot is enabled in settings) Settings

  2. Start calibration process using the snapshot button and keep the camera pointed at the projection. Settings

  3. Judge result preview and accept for permanent upload of correction data Aligned Aligned Aligned


Projectors cannot be found

Make sure your device and the projectors are connected to the same local network and in the same IP-Range. Also ensure that the projector type is supported.

Suboptimal calibration results

  • Ensure that the test patterns for each projector are clearly separated (in single shot mode).

    • adjust the shift, zoom and physical placement of the projectors to increase the amount of overlap between projectors

    • reduce the marker coverage and marker density (in the advanced settings)

  • Alternatively, use multi-shot calibration with a tripod. In this mode the test patterns are captured separately for each projector so test pattern overlapping is not an issue. Calibration data for all corners for each projector is also provided.

  • Capture images closer to the projectors’ positions

  • Try to fill the camera image with the projected image. Digital zoom can be used if necessary.

Warping not enabled on first try on pulse projector

When the warping is not enabled after it has been uploaded, it might be on the projector but not selected. Go into the warping menu of the projector and select the “warping.xml” warp file.

Test patterns are not shown as expected

If you see test patterns shown in the same grid that are not unique, or any of the test patterns are cropped, this means that the resolution in Stacker is not set to the native resolution of the projectors. For information on how to find your projectors’ native resolution please see the ‘Supported Projectors’ section in the introduction.

Connection to the projectors is slow or unreliable

Ensure that the projectors are connected to a source. The source does not have to output at the projectors’ native resolution.