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.