"Christoph Hormann" <Chr### [at] schunteretctu-bsde> wrote in
message news:39803165.D051FC90@schunter.etc.tu-bs.de...
|
| How about employing the RMF function for the ice too, so that the ice is
melting
| in the middle first and later on the coast.

Nice idea, if I could do it.  I'll never know unless I try I suppose, but in
this particular rendering the water is all a single plane.  Guess I might
negate the same mountain isosurface somehow to get the individual lakes
where they already stand.  Could be a challenge for me.
The RMF isn't also usable as a pigment, is it?

Bob

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"Bill DeWitt" <the### [at] earthlinknet> wrote in message
news:39802705@news.povray.org...
| Bob, see my question about Slope dependent texturing in p.g.

Have done so.

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Bob Hughes wrote:
> 
> Nice idea, if I could do it.  I'll never know unless I try I suppose, but in
> this particular rendering the water is all a single plane.  Guess I might
> negate the same mountain isosurface somehow to get the individual lakes
> where they already stand.  Could be a challenge for me.
> The RMF isn't also usable as a pigment, is it?
> 
> Bob

Sure it is, you can use every function as a pigment, there are some of the
megapov-sample scenes using that, like math_pigm.pov in the isosurface dir.

Christoph

--
Christoph Hormann <chr### [at] gmxde>
Homepage: http://www.schunter.etc.tu-bs.de/~chris/

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"Greg M. Johnson" <gre### [at] my-dejanewscom> wrote in message
news:39802CA6.469A2F0F@my-dejanews.com...
| Wonderful. How many objects are we seeing--I'd be even more impressed if
it
| were only one!
|
| Also, doesn't this just blow away the concept of heightfields--wouldn't it
| be impossible to make a non-hideous flythrough if these were mere
| heightfields and one lacked a Cray?

You're right on the mark with that comment Greg.  The circumventing of a
need for smooth height fields to do this sort of thing may make the HF
obsolete, dare I say.  The one drawback is the need to get a fine enough
'accuracy' apparently, among other things I might not know about, which can
slow things up.  The 'eval' and 'method 2' are superb additions.
Oh, yeah.  Yes, just the isosurface with ridged multifractal function and a
water plane, some ground fog, sky_sphere too.  A little detailed info:  24
by 24 unit square isosurface used with the camera traveling about 3 units at
a height of 0.41*y average above the water level.

Bob

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In article <39807635@news.povray.org>, "Bob Hughes" 
<per### [at] aolcom?subject=PoV-News:> wrote:

> Nice idea, if I could do it.  I'll never know unless I try I suppose, 
> but in this particular rendering the water is all a single plane.  
> Guess I might negate the same mountain isosurface somehow to get the 
> individual lakes where they already stand.  Could be a challenge for 
> me.

Just use the RMF function as a function pattern to control the 
melting...you won't even have to change your plane, just the texture of 
the water.


> The RMF isn't also usable as a pigment, is it?

Any isosurface function is useable as a pattern, and any pigment can be 
used in an isosurface function.

-- 
Christopher James Huff - Personal e-mail: chr### [at] maccom
TAG(Technical Assistance Group) e-mail: chr### [at] tagpovrayorg
Personal Web page: http://homepage.mac.com/chrishuff/
TAG Web page: http://tag.povray.org/

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"Chris Huff" <chr### [at] maccom> wrote in message
news:chrishuff-E2F56D.10205127072000@news.povray.org...
|
| Looks like a recently terraformed low-gravity planet...I don't think
| mountains like that would survive long in an atmosphere.

I've seen similarly thin ridges of mountains or hills like this before in
photos or television, but maybe not quite as thin as these turned out.  I
went with a bit of a spikey look to it all.

| Great job...have you tried making bare rock on near-vertical surfaces?
| It looks like a lot of the snow is clinging to very steep slopes.

The first animations I made were like that, this render was afterward when I
changed to a more heavily snowed winter time shifting to melting,
evaporating rather, summer time appearance.  Being all texture and no
substance it is of course physically incorrect anyhow.  I might do a change
of the isosurface to go along with.

Bob

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Oh, okay, I had it in mind the RMF type was set apart from the rest.  Thanks
for telling me, too lazy to look up in the MegaPov html file myself.

Bob

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"Chris Huff" <chr### [at] maccom> wrote in message
news:chrishuff-F3C93D.13042127072000@news.povray.org...
|
| > The RMF isn't also usable as a pigment, is it?
|
| Any isosurface function is useable as a pattern, and any pigment can be
| used in an isosurface function.

Thanks to you too for the quick reply.  I somehow had put the RMF into it's
own category outside the rest in my mind.

Bob

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Bob Hughes wrote:
> 
[...]
> 
> You're right on the mark with that comment Greg.  The circumventing of a
> need for smooth height fields to do this sort of thing may make the HF
> obsolete, dare I say.  The one drawback is the need to get a fine enough
> 'accuracy' apparently, among other things I might not know about, which can
> slow things up.  The 'eval' and 'method 2' are superb additions.
> Oh, yeah.  Yes, just the isosurface with ridged multifractal function and a
> water plane, some ground fog, sky_sphere too.  A little detailed info:  24
> by 24 unit square isosurface used with the camera traveling about 3 units at
> a height of 0.41*y average above the water level.
> 
> Bob

Even though your scene shows the strength of isosurface terrain very good i have
to disagree about heightfields becoming obsolete.  

IMO, their strength is where you apply many functions to the surface that would
take very long to render as an isosurface and most erosion functions would be
nearly impossible with isosurfaces, because they often use iterative algorithms.

Christoph

--
Christoph Hormann <chr### [at] gmxde>
Homepage: http://www.schunter.etc.tu-bs.de/~chris/

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The point is that every time I started to mess with HF's, I wallowed in indecision
about the resolution. If I made it too coarse, I could never do an animation later
of a flyby close up or balls bouncing off of it or a man hiking up it. If I made it
finer, it still wasn't going to be fine enough for whatever use I haven't thought up
yet.

Isosurfaces have the same appeal over HF's that vector art has over 2d  bitmap
painting, and really, 3D over vector and bitmap painting.  When I do my rolling
algorithm, I set up my isosurface in an INC. When I need to accurately compute
normals for the traces which determine particle trajectories, I set my
accuracy=0.00001, when I trace, it's 0.01 or 0.001.

Vector programs didn't render bitmap painting obsolete, per se..............

Christoph Hormann wrote:

> Bob Hughes wrote:
> >
> [...]
> >
> > You're right on the mark with that comment Greg.  The circumventing of a
> > need for smooth height fields to do this sort of thing may make the HF
> > obsolete, dare I say.  The one drawback is the need to get a fine enough
> > 'accuracy' apparently, among other things I might not know about, which can
> > slow things up.  The 'eval' and 'method 2' are superb additions.
> > Oh, yeah.  Yes, just the isosurface with ridged multifractal function and a
> > water plane, some ground fog, sky_sphere too.  A little detailed info:  24
> > by 24 unit square isosurface used with the camera traveling about 3 units at
> > a height of 0.41*y average above the water level.
> >
> > Bob
>
> Even though your scene shows the strength of isosurface terrain very good i have
> to disagree about heightfields becoming obsolete.
>
> IMO, their strength is where you apply many functions to the surface that would
> take very long to render as an isosurface and most erosion functions would be
> nearly impossible with isosurfaces, because they often use iterative algorithms.
>
> Christoph
>
> --
> Christoph Hormann <chr### [at] gmxde>
> Homepage: http://www.schunter.etc.tu-bs.de/~chris/

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