### How to make exponential data curves?

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.

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.

>

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

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

>

> 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.

>

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

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.