Accel and Decel levels

  • In a tutorial in Online Help we learn that +- 100 as Accel and Decel level will make a sinus form, as it does perfectly well. But I am trying to figure out the math behind it. Can anyone enlighten me a bit please?

  • Just to be clear, the +/- button in the calculator is the negation key, so following the keypresses in the tutorial means that you entered the value -100%.


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    This is not easy to explain with just text but let's try....


    - to my understanding:


    An Acceleration of 0% represents a linear transition to the next step, the exit vector, has the same angle as the direction to the next stepvalue.

    An Acceleration of -100% represents a ease-out towards the next stepvalue, the exit vector is horizontal.


    A Deceleration of 0% represents a linear transition from previous stepvalue, the entry vector has same angle as direction from the previous stepvalue.

    A Deceleration of -100% represents an ease-in from previous stepvalue, the entry vector, is is horizontal.


    When entry and exit vector both are horizontal the transition is smooth, as a sinewave


    Acc/Dec with even lower value than -100% represents direction vectors further away than horizontal, in other words in the wrong direction of the target.

    Acc/Dec with positive values represents the equivalent vectors on the other side of the vector of the linear transition, representing a more aggressive entry/exit


    for testing try the following with some fixtures selected:


    At 75

    Next Step

    At 25

    Step 1 + 2

    Accel -100

    Decel -100


    Accel -400

    Decel 200


    Accel 100

    Decel -300



    When the sum of Accel and Decel = -200, the entry and exit vectors are parallel

    When entry and exit vector are parallel, the transition is stepless/smooth


    The math behind is bezier curves, the valueranges are normalized for easier interaction.

  • Ok, so step 1 has a Beziere where point 1 and 3 are fixed and point 2 is variable, and with 2 steps point 1,3 and 5 are fixed and 2 and 4 are variable? And if I am right, does the variations in point 2 and 4 influence the common point 3?

  • I see that when I use your excample 2 on my leftside fixtures and excample 3 on my righthand fixtures I am getting close to sin/cosine. It seems like commandline is the only way to input levels <-100 >100.

  • - seems like the calculator is currently limited to +- 100%

    both encoderturn and commandline can be used to over/undershoot.


    tip:

    if you select the "Move Handles" tool in phaser editor, you can see the bezier control vectors, - also in 1D-layout


    tip2:

    the visualization of bezier vectors has some glitches in 1D layout, when next step also is previous step.

    - so add a third step, to properly visualize in 1D layout the vectors for step 1