How to make small adjustments to sliders in device prop.?

Bug Reports
#1

Pulling my hair out here… it’s been a long time since I used WM, back in version .99, and I may be missing something obvious, but how do i make very small adjustments to a slider in a device’s properties dialog?

Using the mouse is not a realistic option; my laptop has a screen resolution of 1920x1200, and even if i weren’t using the touchpad, but an external mouse, I can’t get fine enough control to change, say, the Persistence value in the Perlin Noise Generator from .438 to .450 – the smallest change it seems to make is all the way up to .469, and that makes a significant difference to the appearance of my terrain, much more than I’m trying for.

I tried using the keyboard, and either the Left/Right arrows or the Up/Down arrows move the slider just as far. So far I haven’t seen a way to directly input a value into the dialog to set the slider to that point; maybe I’m just missing something, but I couldn’t get it to work.

WorldMachine is an excellent program, and I plan on continuing to use it and have fun with it, but when I have a certain idea of what I want my terrain to look like and I can’t (either through my lack of knowledge and experience, or because of program limitations) achieve that end result, it’s rather frustrating…

Maybe someone can point me in the right direction, let me know what i’m doing wrong, or perhaps if it really is a bug/issue in the program, have it looked into and possibly resolved in a future release.

Thanks for taking the time to make it all the way through that rant! :stuck_out_tongue:

–Eilonwy05

#2

Hi,

Well, answering precisely your question (in the dialog): you can’t… :frowning:
However, you can complicate things (which I love to do) by using a Scalar Generator device! It may sound silly, but until there is a better way to do it, that might be the only option :stuck_out_tongue:

Do this:

  • in the Menu chose “World Commands > Preferences”
  • go to the “World Options” tab, and make sure the checkbox “Show parameter inputs (~ tilde key)” is checked, and click “Ok”
    :arrow: Now that you can see the parameter inputs, create a Scalar Generator and connect it to the parameter input for the parameter you wish to fine tune the value. (persistence is the third orange port)

The scalar generator properties will allow you to enter a value with more than enough decimals for almost any need. It only has the discomfort of needing to press ok and change device for setting other values…

Cheers,

#3

Hi Fil,

I wouldn’t say that complicates things too much, since I like to make things complex too for fun sometimes. :smiley: Show Parameter Inputs was on by default, and I hooked up a Scalar Generator to Persistence, easy enough to do…

Problem is, the value that gets set for Persistence isn’t the value I’m entering in the Scalar Generator… :? No matter what number I use, I get a Persistence value that’s somewhere between 75% and 77% of the number I used. I tested it with a number of different values in the generator, all with the same general results; where is the rest of the value going?

I thought that maybe since Persistence doesn’t range from 0 to 1, that somehow the available range for Persistence was modyfying the value I provided, but I wasn’t sure if that was anything realistic…

Anyway, if somebody can try and clear that up for me, I’d appreciate it.

Thanks!

–Eilonwy05

#4

Bug found! :slight_smile:
Stephen knows of it, and it should be an easy thing to fix!

:idea: So it’s time to complexificate things even furtherer more…
Do this :slight_smile: :
:arrow: Two Perlins with the two persistence values around the one you want.
:arrow: Then connect these two Perlins to a Combiner, and average them! To get the persistence you want vary the strength in the Combiner.

Because of what persintence is, you can obtain the same effect this way… If it were the case of a distortion, you couldn’t average it with a combiner… And in that case you really had to wait for a fix…

:slight_smile:

#5

EDIT: I wasn’t quite thinking when I asked about the fractals… after going back to WM it dawned on me that Perlin is a generator, not a parameter in a generator… Thanks for the tip!

a-HA! See, I knew it wasn’t just me doing something wrong… Just to make sure I’ve got this down – will this method work for any type of single- or multi-fractal generated terrains? I was trying to use a Hybrid Multifractal; I would think that your suggested solution would still work, but I wanted to doubly-abso-certain-lutely-positive check. :lol:

#6

Well… to make it short: yes! :slight_smile:
Theoretically, in a Perlin noise function, persistence has to do with height only:

first result in google’s search returned http://freespace.virgin.net/hugo.elias/models/m_perlin.htm:

"a single number is used to specify the amplitude of each frequency. This value is known as Persistence"

Since persisntence is a scale value that is multiplied to whatever noise is being added in the noise function, it ends up being the equivalent of avergaing the same terrain with adequate different persistencies… It has to do with the commutative and transitive properties of multiplication and addition, in math-speech… …or something like that…

If you write a formula donw you get:
(FT = final terrain
OT = original terrain
P = persistence
N = noise)
FT1 = OT + P1N
FT2 = OT + P2N

If you average FT1 and FT2 you get (FT1 + FT2) / 2 (averaging at 50% just to make it simple)
that means OT + N*(P1+P2)/2
which is the same if you had a P3 = (P1+P2)/2… tcha-tchan !

phew! …talk about complicating things!!.. :slight_smile:

In practical terms, if you think there is a great different from P1 = .50000 to P2 = .50001 you can average both and have an equivalent persistence that is .500005… You get free omeopathic persistence differences :smiley: at a finer grain than WM is natively capable of providing…

#7