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Thread: question about PPS and FPS

  1. #1
    Join Date
    Mar 2014

    Default question about PPS and FPS

    hi there.
    Today i converted a show I made in LSX+Riya to Moncha's MNT format to play it on someone elses Moncha.NET DAC.
    I tried getting the settings in both programs the same. both were set to run at 40K.
    but i noticed some flicker with moncha, like it is running at 30K or 35K instead.
    I contacted showtacle about this and this is the reply i got:
    if Moncha draws 1000 point frame, it draws it at 35 fps, it means it draws it at 35*1000 = 35000 pps (35k). While maybe Riya draws it at 40k (40000pps) = 40fps in this case of 1000 points-picture.

    We produce product used by 1000+ people. Can’t afford to destroy scanners, so this won’t change in the near future…
    I thought scanners will display any amount of points at 40K if you tell it to run at 40K and if the points are too little they will just get drawn 'twice'?

    or do i just not understand how pps vs fps work and the flicker i get only with Moncha.NET is from something else?

  2. #2
    Join Date
    Jul 2008
    My momentum is too precisely determined :S


    PPS is determined by the program. The scanners can only display what is being sent to them. It's the program that decides how many times a frame is being redrawn each second. If the program is set at 40 kpps and the frame is 1000 points, the program will send the frame 40 times a second to the DAC.

  3. #3
    Join Date
    Jul 2008
    My momentum is too precisely determined :S


    if you send less points per second, the scanners have more time to reach the next state, hence they go slower.

  4. #4
    Bradfo69's Avatar
    Bradfo69 is offline Pending BST Forum Purchases: $47,127,283.53
    Join Date
    Jul 2010
    Wilmington, DE


    That's the same reason Pangolin limits Quickshow to 30k. Moncha is Showtacle's introductory level software (same as Quickshow is for Pangolin.) Since it's usually newer less experienced people using it, they limit the speed so people don't accidentally ruin their scanners.

    As stated by CMB, less points means less work or chance of damage.

  5. #5
    Join Date
    Jul 2007
    Knoxville, TN, USA


    One possibility, and this is just a "swag" -

    Your original show may have used some LSX-unique capabilities that didn't "translate" cleanly when you converted to another show format.

    I've seen this in the past when converting some Pangolin-based shows to straight ILD format ~
    Some of the frame effects just don't translate well, due to some of the capabilities that are unique to the Pangolin software/hardware combination.

    As far as protecting the scanners -
    Keep in mind that the higher the scan speed, and the larger the scan angle, the harder the scanners have to work.
    Too much of either one could lead to overheating fairly quickly, which can lead to all kinds of interesting scanner & amp failures.

    Been there, done that -
    wasn't fun OR cheap!!

    Metrologic HeNe 3.3mw Modulated laser, 2 Radio Shack motors, and a broken mirror.

  6. #6
    Join Date
    Aug 2006



    there can be done something, but the Effect isnt really great when you trust your Scanners :-)

    Most Programms do a Vector Interpolation. So a Rectangle is only 5 Points, the Rest will be interpolatet during Output.
    If you zoom in from 0 Size the Pointcount will be lower than at full Size where more Points will be interpolatet.
    What you can do in Software is to say that with a low Value of Point Count the Scanrate can be reduced to protect the Scanners.
    Maybe you heard this from you Scanner when the zooming in a Picture from Zero Size "Sweeeeepppp....." :-)
    The Framerate in this Case can be > 150 Fps..but why dont Limit it to 50 Fps or something like that ?

    The Output can be calculatet to get a fixed Frame Rate or just using a fixed pps...if you want to Export something to ILDA
    a fixed Framerate is the better choose.

    But if in Case of Moncha not the Customer can do the Decision i think it like a father talking to his 12 Year old son :-)

    But i think there are also other opinions that this or this is the right way...

  7. #7
    Join Date
    Feb 2007
    Fort Mill, SC USA


    Quote Originally Posted by zorn View Post
    I still think you guys dont understand.
    What im saying is the only way i see not running at 40K when not needed can be called 'protecting' is the same way not keeping your computer on when not needed is protecting it.
    And my point or maybe more of a question is, how is this even the issue? If laser graphic is displayed at 35 fps instead of 40 fps should my human eyes see flickering anyway? wasnt 30 fps the standard?
    Hey Zorn,

    I'm certainly no expert, but you may be missing some of the key points. It is true that most people's brains/eyes can't see more than 30FPS, but "protecting your galvos" is not the only consideration when setting the target speed for a particular rendering. Accurate reproduction of the image is also a major consideration. This is a complicated discussion which you can read about in the many scanner threads on this forum, but in short, if you create a complicated frame with lots of sharp corners, it will likely take more points (via interpolating or additional points at the corners) to make it reproduce accurately at 40K as opposed to 30K. (This of course depends on your galvos, the size of the image projected, etc.)

    Apparent brightness of the projected image is another consideration. This may be more of a factor in beam shows, but you should be able to notice the difference between 18K and 40K.

    There's probably several more points and clarification that there more experienced folks can add.

    Quote Originally Posted by zorn View Post
    i dont think quickshow neither lsx have some super secret magic code in them that can reduce flickering without any human set settings.
    Similar to programs like Pangolin's products, LSX has advanced rendering capabilities that are not simply blindly rendering the information reflected in an ILDA frame. This has been discussed in other threads in the past.

    "Help, help, I'm being repressed!"

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