3d quad: Increase intensity using multiple copies. Why not the intensity of one instance?

  • I found that I could double/triple etc the output light intensity of the 3d Quad Distort actor, if I simply connect multiple copies of this actor to the same video input. Why I cannot achieve the same result by increasing the intensity over 100 % in a single instance of this actor? What is the meaning of 100 % intensity in 3d Quad Distort actor?

  • Beta Platinum

    I can only assume this a fluke. Its bad practice to send more than one source into a single input (unless you have toggles, routers, etc before the feeds)

    Technically the actor will get confused and glitch and not know which feed to accept; the top line normally takes priority I find. 
  • Tech Staff

    Well I don't know why the 3D Quad Distort actor is limited to 100% regarding brightness, I am sure there is a reason. But you can get the same result with one 3D Quad Distort and a Contrast adjust actor (where "in max" is set to 33) as if you use three 3D Quad Distort actors.


  • Dear All,

    Well, the OpenGL color modulation values only range from 0.0 to 1.0 -- you can't actually use, for instance, 2.0\. So that's the simple reason it's not there.
    Best Wishes,

  • Hi Michel,
    Yes Contrast adjust seems to do the trick. 

    Hi Mark,

    The question, however, still remains how is it possible to fool opengl into lighting the same pixel with double intensity by drawing to the same pixel twice.

  • Dear Eight,

    Well, one way is to do the the way you're doing it: use two actors. The other way would be to repetitively draw the image in the plugin. But the best way (fastest) would be to write an OpenGL shader to do it. But that's not on my dance card at the moment, as I'm working on other important improvements. I'll consider it once I get through the next release.
    Best Wishes,

  • @Mark,

    So, duplicating projectors is a trick I use a lot when faced with content that needs more oomph. 
    Which has system less overhead - duplicating projectors or using the contrast actor?

    As an aside, I'd love to do this sort of thing with an actor that replicates the Shadow-Highlight functions in Premiere and Photoshop!


  • Tech Staff


    If I make the Test I have following results.

    1. Movie Player - Projector
    cycles: 130     VPO: 35    FPS: 25

    2. Movie Player - contrast adjust (in max 33) - Projector
    cycles: 100     VPO: 73    FPS: 24.5

    3. Movie Player - 3x Projector
    cycles: 130     VPO: 38    FPS: 25

    4. CI Movie Player - 3x CI Projector
    cycles: 160     VPO: 11    FPS: 25

    So copying the projector is the better solution, CI or none CI actors.


  • Hey,

    I use the double or triple projectors all the time.  Was a bit tricky in this last show because I was spacing a dance piece with a lighting designer, and everyone had to wait while I tripled the projector adjustments...  i.e. adjust image placement on stage, then triple the projector and link to the video stream, wave generators to intensities etc so the crew could see how it looked live.  Or for fun I could vary it by adjusting the position on each projector.

    Not that big a deal, a few seconds each time.  But I felt it was a great way to introduce user error!

    I just tried a custom actor to see if it would be easier (sample project attached).  Three projectors inside a user actor, nothing fancy except tripling the projection.

    Spin, for instance wouldn't be tripled but just matched on the three projectors.  Intensity is the only cumulative input for projectors, as long as you are additive mode.


  • PS that previous post has a triple projector user actor I created.  Let me know if I did it right... never shared an actor on here before.