How do I create one big stage that spans the output of three projectors?

  • This is surely straightforwards, but I can't figure it out...

    I have three projectors attached to my computer. I am not using a TH2Go
    I would like to project them on to a wall so that their outputs are stacked one above the other.
    The audience sees a projection screen that is (say) 2160px high and 1280px wide (3 x 720p)
    I would like to project an object that appears at the top of the top screen and moves all the way down to the bottom of the bottom screen.

    I would also like to project an image that spans all three projector images.

    How do I do these things?!



  • Tech Staff

    Heres how I would do this.

    Setup your stages to match your projectors resolutions.
    Add a 'Background Color' actor and set its size to match your 2160 x 1280 _canvas_ size.  (you may want to change the preferences scale to setting to 'largest')
    Build your video up on this _canvas_ (background)_,_ with mixers etc.. to create the output you want.
    Before routing to the projectors, use the 'Crop' actor to cut the large video into 3 matching 720p feeds that you then connect to your projector actors.

  • Thanks, Ryan.

    Maybe I'm being a bit dim, but I'm having trouble figuring out your instructions.
    Perhaps I wasn't clear. Here's what I'd like the audience to see: 01.mp4?dl=0

  • Izzy Guru


    See attached patch for one way to do it.

    Best Michel

  • Tech Staff

    OK, I played with this a bit, since Crop didn't do exactly what I expected... and Michels solution required a warp/stretch.
    The solution is the 'Chop Pixels' actor.

    Attached is a test file with a few approaches.
    Chop Pixels (top, orange ball) is my choice for best approach.


  • I learned a neat trick form @mark recently

    Hook up your image to a 3d projector, set the destination to "render", and create a virtual stage with your desired size. Then output that virtual stage to chop pixel actors and split it out to three projectors.
    Maybe useful in addition to the above tips.

  • Dear All,

    Because of this discussion, I created a handy user actor to be able to chop an image into a specific number of horz/vert divisions, and then to select which portion you want to appear at the output. Have a look here:
    Best Wishes,

  • Thank you so much everyone.

    More amazing things about Isadora: many ways to skin a cat, and a great, responsive, community of users and support.

    Ryan and Michel, thanks for your suggestions, and Mark, thanks so much for the user actor. Guys, I really appreciate your help.

    @fubbi, that's a great tip, thanks!