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From: Kenneth
Subject: ivy on a tree WIP
Date: 19 Jan 2006 02:15:01
Message: <web.43cf3b13e1be95c0dbcfc3c90@news.povray.org>
Hi, all!

My first post at p.b.i.

A rather complex, multi-TRACE experiment, using #while loops of course, with
LOTS of conditional #if's and rand calls.  And, for the ivy leaves, that
magical Point_At_Trans macro, in transforms.inc.

I purposely didn't make use of any of the tree or hair-making macros
available (or look at their code), as I wanted to see what I could come up
with by myself.  The trial-and-error method!

The point of this was to create a wildly-curving object (the tree, an sPatch
model) and have the trace operations accurately follow its shape no matter
where.

Right now, the ivy isn't actually attached to the vines--but there are so
many leaves to hide that fact, *hopefully* it's not apparent.

Each vine is a union of short cylinders. (No "branching" yet.) I tried
sphere_sweeps for the vines, using the cubic_spline type, but the result
looked like I had sprayed the tree with Silly String. Too curvy. (I suppose
I could try another spline type, with more control points, and massage
their values, but it was difficult enough, code-wise, dealing with just a
cubic spline!) And sphere_sweeps take a *long* time to render. Besides, I
kind of like the sharper "angular" look of the cylinders. Oh, and I
purposely made the bottom of the vines come out of the ground and "reach"
for the tree--as if they are slowly, inexorably pulling the poor tree down
into Mother Earth. (On my to-do list is attaching ivy directly to those
cylinders.)

Hope you like it!

Ken


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From: Kenneth
Subject: Re: ivy on a tree WIP
Date: 19 Jan 2006 02:40:01
Message: <web.43cf4224238f31cedbcfc3c90@news.povray.org>
And here's a close-up...


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From: Thomas de Groot
Subject: Re: ivy on a tree WIP
Date: 19 Jan 2006 03:22:42
Message: <43cf4c52@news.povray.org>
"Kenneth" <kdw### [at] earthlinknet> schreef in bericht
news:web.43cf4224238f31cedbcfc3c90@news.povray.org...
> And here's a close-up...
>
Excellent work, Kenneth! Congratulations!

I don't care about the cylinders, although in the close-up, they are perhaps
a little bit too conspicuous/artificial. In any case, i like it!

Thomas


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From: Kenneth
Subject: Re: ivy on a tree WIP
Date: 19 Jan 2006 03:50:00
Message: <web.43cf511d238f31cedbcfc3c90@news.povray.org>
"Thomas de Groot" <t.d### [at] internlnet> wrote:

> >
> Excellent work, Kenneth! Congratulations!
>
> I don't care about the cylinders, although in the close-up, they are perhaps
> a little bit too conspicuous/artificial. In any case, i like it!
>
> Thomas

Thanks; much appreciated.

Yeah, I agree. My aim is to find some kind of shape that's "inbetween"
strickly angular and strickly Silly String.May yet have to use a
sphere_sweep, with more complicated control of its points. What a
daunting task.

Ken


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From: Marc Jacquier
Subject: Re: ivy on a tree WIP
Date: 19 Jan 2006 03:55:16
Message: <43cf53f4@news.povray.org>

news:web.43cf3b13e1be95c0dbcfc3c90@news.povray.org...
> Hi, all!
>
> My first post at p.b.i.
>

Very well done!
Maybe you could get the nices closer to the trunk at the bottom?
And some grapes of those  berries we when children used as projectiles for
peashooters?
http://www.wildlife-gardening.org.uk/Galleries%5CPlants%5CClimbers%5Civy-fruiting-050306.JPG

Marc


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From: Marc Jacquier
Subject: Re: ivy on a tree WIP
Date: 19 Jan 2006 04:04:45
Message: <43cf562d$1@news.povray.org>

news:43cf53f4@news.povray.org...
> Maybe you could get the *nices* closer to the trunk at the bottom?
O_ops!  one had to read *vines* of course.

Bloody untrusty fingers I got :-s
Marc


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From: Bill Pragnell
Subject: Re: ivy on a tree WIP
Date: 19 Jan 2006 05:00:01
Message: <web.43cf629c238f31ce731f01d10@news.povray.org>
That is truly excellent. Very realistic. I agree that the vines look a
little too angular near the base, but I think they look fine further up.
Did you make the leaves yourself too?

The straight-line approach... perhaps you could join the cylinders with
torus segments? I believe there are some macros for connecting points with
those (or you could write one quite easily). That would save time over the
sweeps. Maybe the radius of the joins could be varied randomly too.

Just out of interest, what sort of parse time vs render time are you looking
at?

I look forward to more on this
Bill


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From: Jim Charter
Subject: Re: ivy on a tree WIP
Date: 19 Jan 2006 05:11:13
Message: <43cf65c1@news.povray.org>
Kenneth wrote:
Excellent work, and a subject close to my own heart, so I can doubly 
appreciate your efforts.

Some test renders from one of my many wip's


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From: Remy Closset
Subject: Re: ivy on a tree WIP
Date: 19 Jan 2006 05:51:17
Message: <43cf6f25@news.povray.org>
Very good job. We all know that natural scenery is the most difficult thing 
to do.



web.43cf4224238f31cedbcfc3c90@news.povray.org...
> And here's a close-up...
>


--------------------------------------------------------------------------------


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From: Kenneth
Subject: Re: ivy on a tree WIP
Date: 19 Jan 2006 06:25:00
Message: <web.43cf75c4238f31cedbcfc3c90@news.povray.org>
"Bill Pragnell" <bil### [at] hotmailcom> wrote:
> That is truly excellent. Very realistic. I agree that the vines look a
> little too angular near the base, but I think they look fine further up.
> Did you make the leaves yourself too?
>

Yes, as a single sPatch model, painted with a (rather simplified) Photoshop
artwork overlay, based on some photos I took.  Luckily for me, right
outside my apartment window is a gigantic old gnarly tree, practically
engulphed in ivy half-way up its trunk. So I had daily inspiration!

> The straight-line approach... perhaps you could join the cylinders with
> torus segments?

A very neat idea, I'll have to try that.  At one point, I was considering
using half a torus to try and recreate where vines actually cross over each
other... the "bump."  But I concluded it would have involved a rather major
re-write of my tracing code...at the very least!
>
> Just out of interest, what sort of parse time vs render time are you looking
> at?

I should have made a note of that, but didn't. Total render time (using
cylinders for vines) was between 3 and 4 hours on my 400MHZ  Pentium II,
using AA 0.2.  Parse time was a small fraction of that--perhaps 5-to-10
minutes at most. I actually aborted the sphere_sweep render about half-way
through! But I'll run that version again and report back (the code is still
intact.)


Ken


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