How to make exponential data curves?


    Mar 31 2008 | 4:24 am
    Hi, I am Peter Ostry, I am new in this forum and new to Max. Please excuse me if my questions are "common knowledge".
    I am looking for the best way to let a slider run
    - from 0-90 and stop
    - or from 90-0 and stop
    - with adjustable speed
    - following several selectable exponential curves
    I looked into the "bline" object and it seems to do what I want. I can load different lists to control the curve and the direction. But I am a bit unsure if I chose the right technique. I don't need ultrasmooth operation but writing the lists is rather tedious. And I need a couple of them and one set for for each direction. Is there another way to create exponential curves?
    I think there must be a formula but I don't know which one (I am lousy in maths) nor do I know how and in which object to use it. If someone knows a trick for easy creation of exponential curves, I appreciate any suggestion or hints where to look in the Max manual.

    • Mar 31 2008 | 5:48 am
      hey
      I would use just a line going from one number to the next over a
      chosen time and feed it into an [expr] containing the formula with the
      one below being the easiest
      maybe you can get a [expr $f1 * pow($f1,1)] you can change the last
      number by substituting it with $f2 to get a faster or slower
      exponential function
      hope this helps
      On 31 Mar 2008, at 06:24, Peter Ostry wrote:
      >
      > Hi, I am Peter Ostry, I am new in this forum and new to Max. Please
      > excuse me if my questions are "common knowledge".
      >
      > I am looking for the best way to let a slider run
      > - from 0-90 and stop
      > - or from 90-0 and stop
      > - with adjustable speed
      > - following several selectable exponential curves
      >
      > I looked into the "bline" object and it seems to do what I want. I
      > can load different lists to control the curve and the direction. But
      > I am a bit unsure if I chose the right technique. I don't need
      > ultrasmooth operation but writing the lists is rather tedious. And I
      > need a couple of them and one set for for each direction. Is there
      > another way to create exponential curves?
      >
      > I think there must be a formula but I don't know which one (I am
      > lousy in maths) nor do I know how and in which object to use it. If
      > someone knows a trick for easy creation of exponential curves, I
      > appreciate any suggestion or hints where to look in the Max manual.
      >
    • Mar 31 2008 | 7:47 am
      Yes it helped, much easier. Thanks.
      Just one problem due to my lack of mathematical knowledge:
      It works now as I need it but it starts always slow and accellerates on the way. Can I reverse that, to let it start fast and become slower? I tried 0.5 as the last number in the formula and less, but I don't see much of a difference. Negative numbers do not work.
      Quote: pieter.coussement wrote on Sun, 30 March 2008 23:48
      ----------------------------------------------------
      > I would use just a line going from one number to the next over a
      > chosen time and feed it into an [expr] containing the formula with the
      > one below being the easiest
      > maybe you can get a [expr $f1 * pow($f1,1)] you can change the last
      > number by substituting it with $f2 to get a faster or slower
      > exponential function
      >
      > hope this helps
      >
      >
      > On 31 Mar 2008, at 06:24, Peter Ostry wrote:
      > > I am looking for the best way to let a slider run
      > > - from 0-90 and stop
      > > - or from 90-0 and stop
      > > - with adjustable speed
      > > - following several selectable exponential curves
    • Mar 31 2008 | 8:39 am
      A nice no-brainer for curves is Tristan Jehan's mapper
      object - see http://web.media.mit.edu/~tristan/
      (Mac-only, atm, I'm afraid...)
      cheers
      Roger
      --- Peter Ostry wrote:
      >
      > Hi, I am Peter Ostry, I am new in this forum and new
      > to Max. Please excuse me if my questions are "common
      > knowledge".
      >
      > I am looking for the best way to let a slider run
      > - from 0-90 and stop
      > - or from 90-0 and stop
      > - with adjustable speed
      > - following several selectable exponential curves
      >
      > I looked into the "bline" object and it seems to do
      > what I want. I can load different lists to control
      > the curve and the direction. But I am a bit unsure
      > if I chose the right technique. I don't need
      > ultrasmooth operation but writing the lists is
      > rather tedious. And I need a couple of them and one
      > set for for each direction. Is there another way to
      > create exponential curves?
      >
      > I think there must be a formula but I don't know
      > which one (I am lousy in maths) nor do I know how
      > and in which object to use it. If someone knows a
      > trick for easy creation of exponential curves, I
      > appreciate any suggestion or hints where to look in
      > the Max manual.
      >
    • Mar 31 2008 | 8:55 am
      Another let-the-object-do-the-thinking approach are lp.scampf and lp.scampi from Litter Power. These run on both Mac OS and Windows and give you more curve variations than anything else: exponential, parabolic, logarithmic, S-curves, U-curves, linear with a "kink" point...
      Part of Litter Starter Pack, available at the URL below.
      Best,
      Peter
    • Mar 31 2008 | 8:33 pm
      Quote: roger.carruthers wrote on Mon, 31 March 2008 02:39
      ----------------------------------------------------
      > A nice no-brainer for curves is Tristan Jehan's mapper
      > object - see http://web.media.mit.edu/~tristan/
      > (Mac-only, atm, I'm afraid...)
      Thanks, this seems to be what I need for now.
      And I am also Mac-only, so we fit together.
      ---
      The Litter Pack looks also interesting, but is a bit too big for me. I don't want to start with many externals. I am pretty sure that I would make a big mess until I discover how to organize my Max work. Basics and just few and little helpers are more important at the moment.