Hi,

I have seen some very nice isosurface ridgedMF-Mountains, esp. in the "Icy
coast"-series. But I can't find params which give me at least comparable
results. The values of Cristoph Hormann result in a bunch of rocks (because
they are from a different tool) and my experiments don't even look like any
natural formations.
I would be very glad if anyone could point me in the right direction with an
initial set of values.

Thank you,

Marc-Hendrik

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"Marc-Hendrik Bremer" <Mar### [at] t-onlinede> wrote in message
news:39886ae3@news.povray.org...
|
| I have seen some very nice isosurface ridgedMF-Mountains, esp. in the "Icy
| coast"-series. But I can't find params which give me at least comparable
| results. The values of Cristoph Hormann result in a bunch of rocks
(because
| they are from a different tool) and my experiments don't even look like
any
| natural formations.
| I would be very glad if anyone could point me in the right direction with
an
| initial set of values.

I was using a fairly high octaves number of 7 to do the mountains I had made
for the animation I'm currently playing in.
I was generalizing greatly the affect each parameter had:

#declare H = 0.25; // roughening<>smoothing
#declare Lacunarity = 4; // roughening<>smoothing
#declare Octaves = 7; // smoothing<>roughening (computationally intensive
higher)
#declare Offset = 0.5; // height (suggested to start as 1 in the Doc.)
#declare Gain= 2; // smoothing<>roughening (I used too much maybe)

Bob

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Thanks, Bob, but I don't get it!
I'm obviously something wrong. When I use your values, all I get is a bunch
of smooth "rocks" - nice in a way and maybe useful someday, but not at all
what I am looking after :-) No plain, no "closed" formation, more like
asteroids in space.

This is my statement:

#declare H = 0.25; // roughening<>smoothing
#declare Lacunarity = 4; // roughening<>smoothing
#declare Octaves = 7; // smoothing<>roughening (computationally intensive
higher)
#declare Offset = 0.5; // height (suggested to start as 1 in the Doc.)
#declare Gain= 2; // smoothing<>roughening (I used too much maybe)

isosurface{
    function{"ridgedmf", <H, Lacunarity, Octaves, Offset, Gain>}
    method 1
    // method 2
    // eval
    // max_gradient 4

    accuracy 0.0001
    contained_by{box -1,1}
    pigment{White}
}

With method 2 I get a totally gray pic (background {rgb 0.3}) even with
max_gradient 5 (eval says max_gradient is ~3.7).

Any ideas what I'm doing wrong?

Thanks again,

Marc-Hendrik


Bob Hughes schrieb in Nachricht <3988ed7a@news.povray.org>...
>"Marc-Hendrik Bremer" <Mar### [at] t-onlinede> wrote in message
>news:39886ae3@news.povray.org...
>|
>| I have seen some very nice isosurface ridgedMF-Mountains, esp. in the
"Icy
>| coast"-series. But I can't find params which give me at least comparable
>| results. The values of Cristoph Hormann result in a bunch of rocks
>(because
>| they are from a different tool) and my experiments don't even look like
>any
>| natural formations.
>| I would be very glad if anyone could point me in the right direction with
>an
>| initial set of values.
>
>I was using a fairly high octaves number of 7 to do the mountains I had
made
>for the animation I'm currently playing in.
>I was generalizing greatly the affect each parameter had:
>
>#declare H = 0.25; // roughening<>smoothing
>#declare Lacunarity = 4; // roughening<>smoothing
>#declare Octaves = 7; // smoothing<>roughening (computationally intensive
>higher)
>#declare Offset = 0.5; // height (suggested to start as 1 in the Doc.)
>#declare Gain= 2; // smoothing<>roughening (I used too much maybe)
>
>Bob
>
>
>

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"Marc-Hendrik Bremer" <Mar### [at] t-onlinede> wrote in message
news:39896757@news.povray.org...
| Thanks, Bob, but I don't get it!

Sorry for the delay in replying.  Been away from the newsgroups a short
while.

| I'm obviously something wrong. When I use your values, all I get is a
bunch
| of smooth "rocks" - nice in a way and maybe useful someday, but not at all
| what I am looking after :-) No plain, no "closed" formation, more like
| asteroids in space.

method 1 simply doesn't seem compatible from what I had seen.  Use only
'eval' and 'accuracy' and nothing else along with method 2 to see
"mountains".
But where you really went wrong is by not using a starting parameter (if
that's the word for it).

 #declare H = 0.25; // roughening<>smoothing
 #declare Lacunarity = 4; // roughening<>smoothing
 #declare Octaves = 7; // smoothing<>roughening (computationally intensive
higher)
 #declare Offset = 0.5; // height (suggested to start as 1 in the Doc.)
 #declare Gain= 2; // smoothing<>roughening (I used too much maybe)

#declare Fun=
function {"ridgedmf", <H, Lacunarity, Octaves, Offset, Gain>}

 isosurface {
     function { y - Fun(x,y,z) } // function is applied to x,y,x and
interacted according to y
      method 2
      eval
      accuracy 0.0001
     contained_by {box -1,1}
    pigment {White}
 }

That should get you something.

Bob

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YES!!!!

Thank you very much, Bob. I do not really know why it works now, but that's
okay for me and for now :-)

Marc-Hendrik

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