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  Treat a mesh as an isofunction (Message 1 to 5 of 5)  
From: SecondCup
Subject: Treat a mesh as an isofunction
Date: 29 Sep 2016 19:30:01
Message: <web.57ed6aa5190b26257f17efbc0@news.povray.org>
Hi,

I'm wondering if there is a way to treat a mesh2 as an isosurface. I'm pretty
new to pov-ray (some will notice my regular contribution to the 'newusers'
forum) so still figuring out a lot of the stuff. This one might be straight
forward.

I have a mesh2 file of something that looks like a few pancakes layered on top
of one another. This was created using Accutrans that converted my
wireframe/solid/whatever-ya-wanna-call-it.dxf into a .pov file (version 3.5).
I want to make these pancake type surfaces look like they are stone, or a
roughly chiseled piece of rock.

Looking around online, I found an excellent rendering of a sandstone by PM 2Ring
on this site. The wrinkly patterns and depth of the bumps are perfect for what I
am looking for. Is it possible to make my pancake-type-thingy.pov have the same
texture as the sandstone in PM 2Ring's code?

He uses functions and isosurfaces that I'm still trying to get my head around,
is there someone out there who can tell me if they are mergeable?

Attached are both codes...You'll notice I have been able to incorporate the
colours into my file.


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From: SecondCup
Subject: Re: Treat a mesh as an isofunction
Date: 29 Sep 2016 19:50:01
Message: <web.57ed6fd9db3efb27f17efbc0@news.povray.org>
Sorry the title should read "Treat a mesh2 as an isosurface"


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From: Thomas de Groot
Subject: Re: Treat a mesh as an isofunction
Date: 30 Sep 2016 07:18:33
Message: <57ee11c9@news.povray.org>
On 29-9-2016 21:25, SecondCup wrote:
> Hi,
>
> I'm wondering if there is a way to treat a mesh2 as an isosurface. I'm pretty
> new to pov-ray (some will notice my regular contribution to the 'newusers'
> forum) so still figuring out a lot of the stuff. This one might be straight
> forward.

As far as I know: no.

>
> I have a mesh2 file of something that looks like a few pancakes layered on top
> of one another. This was created using Accutrans that converted my
> wireframe/solid/whatever-ya-wanna-call-it.dxf into a .pov file (version 3.5).
> I want to make these pancake type surfaces look like they are stone, or a
> roughly chiseled piece of rock.
>
> Looking around online, I found an excellent rendering of a sandstone by PM 2Ring
> on this site. The wrinkly patterns and depth of the bumps are perfect for what I
> am looking for. Is it possible to make my pancake-type-thingy.pov have the same
> texture as the sandstone in PM 2Ring's code?

Yes. Although the pancakes are very smooth, to get a stone-like effect 
you need to add a normal to the texture and play with scale and rotation 
to get the effect you desire.

The isosurface PM2Ring is using is sufficiently rough by itself to just 
use the texture without a normal. The pancakes on the other hand are too 
smooth and you have to adapt to get a similar effect. Note that my 
example is only one of many. You should play with all the possibilities 
offered by POV-Ray to get what you want.

One thing I would like to suggest, if you want to go along with these 
pancakes, is to try and use 'Subdivision' and then 'Displacement' in 
Poseray. That way you would make the pancakes much more interesting.

>
> He uses functions and isosurfaces that I'm still trying to get my head around,
> is there someone out there who can tell me if they are mergeable?

As said above, no.

>
> Attached are both codes...You'll notice I have been able to incorporate the
> colours into my file.
>

I re-attach the file with a couple of additions/corrections. Switch off 
most of the fill-in lights. Set to version 3.7 and standard assumed_gamma 1.

-- 
Thomas


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From: SecondCup
Subject: Re: Treat a mesh as an isofunction
Date: 30 Sep 2016 18:40:01
Message: <web.57eeb173db3efb2be6b2e390@news.povray.org>
Thomas de Groot <tho### [at] degrootorg> wrote:
> On 29-9-2016 21:25, SecondCup wrote:
> > Hi,
> >
> > I'm wondering if there is a way to treat a mesh2 as an isosurface. I'm pretty
> > new to pov-ray (some will notice my regular contribution to the 'newusers'
> > forum) so still figuring out a lot of the stuff. This one might be straight
> > forward.
>
> As far as I know: no.
>
> >
> > I have a mesh2 file of something that looks like a few pancakes layered on top
> > of one another. This was created using Accutrans that converted my
> > wireframe/solid/whatever-ya-wanna-call-it.dxf into a .pov file (version 3.5).
> > I want to make these pancake type surfaces look like they are stone, or a
> > roughly chiseled piece of rock.
> >
> > Looking around online, I found an excellent rendering of a sandstone by PM 2Ring
> > on this site. The wrinkly patterns and depth of the bumps are perfect for what I
> > am looking for. Is it possible to make my pancake-type-thingy.pov have the same
> > texture as the sandstone in PM 2Ring's code?
>
> Yes. Although the pancakes are very smooth, to get a stone-like effect
> you need to add a normal to the texture and play with scale and rotation
> to get the effect you desire.
>
> The isosurface PM2Ring is using is sufficiently rough by itself to just
> use the texture without a normal. The pancakes on the other hand are too
> smooth and you have to adapt to get a similar effect. Note that my
> example is only one of many. You should play with all the possibilities
> offered by POV-Ray to get what you want.
>
> One thing I would like to suggest, if you want to go along with these
> pancakes, is to try and use 'Subdivision' and then 'Displacement' in
> Poseray. That way you would make the pancakes much more interesting.
>
> >
> > He uses functions and isosurfaces that I'm still trying to get my head around,
> > is there someone out there who can tell me if they are mergeable?
>
> As said above, no.
>
> >
> > Attached are both codes...You'll notice I have been able to incorporate the
> > colours into my file.
> >
>
> I re-attach the file with a couple of additions/corrections. Switch off
> most of the fill-in lights. Set to version 3.7 and standard assumed_gamma 1.
>
> --
> Thomas

Thank you for the advice Thomas, it's really appreciated.

I scaled it to 500 and added some turbulence. It looks pretty good. Now to fine
tune the lighting :)


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From: Thomas de Groot
Subject: Re: Treat a mesh as an isofunction
Date: 1 Oct 2016 06:51:04
Message: <57ef5cd8$1@news.povray.org>
On 30-9-2016 20:39, SecondCup wrote:
> Thank you for the advice Thomas, it's really appreciated.
>
> I scaled it to 500 and added some turbulence. It looks pretty good. Now to fine
> tune the lighting :)
>

You are welcome :-)

To my remark concerning Poseray's Subdivision and Displacement, I must 
add that the quality of the original object is crucial of course. I 
noticed that the pancakes were rather simple meshes so the above would 
not change much at all. A better initial mesh should be preferred. and 
would give more interesting results.

-- 
Thomas


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