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  How to model "connecting dirt"? (Message 1 to 8 of 8)  
From: Tommy377
Subject: How to model "connecting dirt"?
Date: 30 Sep 2011 01:25:07
Message: <web.4e8550be646b5d89b9815d200@news.povray.org>
Hi. I want to make a certain kind of transition between an object and the
ground.

To see what I mean, look at the picture "Virtual Joy of Life" in the POV-Ray
Hall of Fame. There, at the ground, the transition from the stairstep to the
rest of the ground. That's what I mean. It's a smooth, but crunchy transition
somehow.

At first, I tried to achieve this effect by using the same technique as shown in
the "wallstucco"-example that came with POV-Ray 3.6., but it didn't turn out the
way I wanted it to be.

The problem is, that I need to "connect" a regular face like a cube to a more or
less random surface. Like in the Picture "Virtual Joy of Life".

How can I do this?


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From: Thomas de Groot
Subject: Re: How to model "connecting dirt"?
Date: 30 Sep 2011 03:09:33
Message: <4e856b2d$1@news.povray.org>
On 30-9-2011 7:19, Tommy377 wrote:
> Hi. I want to make a certain kind of transition between an object and the
> ground.
>
> To see what I mean, look at the picture "Virtual Joy of Life" in the POV-Ray
> Hall of Fame. There, at the ground, the transition from the stairstep to the
> rest of the ground. That's what I mean. It's a smooth, but crunchy transition
> somehow.
>
> At first, I tried to achieve this effect by using the same technique as shown in
> the "wallstucco"-example that came with POV-Ray 3.6., but it didn't turn out the
> way I wanted it to be.
>
> The problem is, that I need to "connect" a regular face like a cube to a more or
> less random surface. Like in the Picture "Virtual Joy of Life".
>
> How can I do this?
>
>
>
I am not sure how Tom Aust did the *physical* transition (mesh or 
isosurface, combining the step stone and the ground) but the texture 
probably involves a slope pattern with altitude control.

Building a mesh is best done with an adequate modeller like Wings3D; an 
isosurface can be made very realistic-looking but is also fairly complex 
to build, and slow(er) to render.

Thomas


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From: Jaime Vives Piqueres
Subject: Re: How to model "connecting dirt"?
Date: 30 Sep 2011 05:17:43
Message: <4e858937$1@news.povray.org>
On 30/09/11 09:09, Thomas de Groot wrote:
> On 30-9-2011 7:19, Tommy377 wrote:
>> Hi. I want to make a certain kind of transition between an object
>> and the ground.
>>
>> To see what I mean, look at the picture "Virtual Joy of Life" in
>> the POV-Ray Hall of Fame. There, at the ground, the transition from
>> the stairstep to the rest of the ground. That's what I mean. It's a
>> smooth, but crunchy transition somehow.
>>
> I am not sure how Tom Aust did the *physical* transition...

   After zooming in on the picture, I guess the whole ground is just one
heightfield, including the step and the interior ground, which were
textured differently by using a gradient y pattern, as you said.

   Anyhow, what Tommy wanted could be achieved in a similar way, by
painting/rendering a heightfield which takes into account the objects
that will be placed over it. Not easy nor simple, but feasible...

   Regards,

--
Jaime


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From: Thomas de Groot
Subject: Re: How to model "connecting dirt"?
Date: 30 Sep 2011 07:44:08
Message: <4e85ab88$1@news.povray.org>
On 30-9-2011 11:17, Jaime Vives Piqueres wrote:
>
> After zooming in on the picture, I guess the whole ground is just one
> heightfield, including the step and the interior ground, which were
> textured differently by using a gradient y pattern, as you said.
>
> Anyhow, what Tommy wanted could be achieved in a similar way, by
> painting/rendering a heightfield which takes into account the objects
> that will be placed over it. Not easy nor simple, but feasible...
>

Height_field of course! You are right; I forgot that. It explains the 
crude, but effective (here), transition between the step and the dirt.

Your technique would work very well I guess, with an intermediate 
orthographic overhead render for localising the exact position of the 
objects needing dirt accumulation, then painting the dirt height_field 
image from that. Interesting idea: something I should try... Thanks Jaime!

Thomas


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From: Thomas de Groot
Subject: Re: How to model "connecting dirt"?
Date: 30 Sep 2011 08:02:55
Message: <4e85afef$1@news.povray.org>
...and you suggested exactly this to me maybe a year ago or longer for 
the ruined columns image, and I forgot all about it ;-)

Thomas


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From: Jaime Vives Piqueres
Subject: Re: How to model "connecting dirt"?
Date: 30 Sep 2011 08:37:15
Message: <4e85b7fb$1@news.povray.org>
On 30/09/11 14:02, Thomas de Groot wrote:
> ...and you suggested exactly this to me maybe a year ago or longer for
> the ruined columns image, and I forgot all about it ;-)
>

Me too! :)



--
Jaime


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From: Tommy377
Subject: Re: How to model "connecting dirt"?
Date: 1 Oct 2011 04:45:00
Message: <web.4e86d2afa14e3a7eed0bce00@news.povray.org>
Thomas de Groot <tenDOTlnDOTretniATtoorgedDOTt> wrote:
> On 30-9-2011 11:17, Jaime Vives Piqueres wrote:
> >
> > After zooming in on the picture, I guess the whole ground is just one
> > heightfield, including the step and the interior ground, which were
> > textured differently by using a gradient y pattern, as you said.
> >
> > Anyhow, what Tommy wanted could be achieved in a similar way, by
> > painting/rendering a heightfield which takes into account the objects
> > that will be placed over it. Not easy nor simple, but feasible...
> >
>
> Height_field of course! You are right; I forgot that. It explains the
> crude, but effective (here), transition between the step and the dirt.
>
> Your technique would work very well I guess, with an intermediate
> orthographic overhead render for localising the exact position of the
> objects needing dirt accumulation, then painting the dirt height_field
> image from that. Interesting idea: something I should try... Thanks Jaime!
>
> Thomas

Hi, thanks for replying. I just would like to check if I do understand what
you're talking about:
It's about an algorithm that "sweeps" the heightfield into the shape of an
object placed over it, by making its slope staller and staller the more close
the heightfield gets to that object, right?


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From: Thomas de Groot
Subject: Re: How to model "connecting dirt"?
Date: 1 Oct 2011 10:26:04
Message: <4e8722fc$1@news.povray.org>
On 1-10-2011 10:43, Tommy377 wrote:
> Hi, thanks for replying. I just would like to check if I do understand what
> you're talking about:
> It's about an algorithm that "sweeps" the heightfield into the shape of an
> object placed over it, by making its slope staller and staller the more close
> the heightfield gets to that object, right?

No. the technique makes use of a paint program, taking an orthographic 
overhead image of the scene as basis, and painting the dirt in shades of 
grey on a separate layer, then applying that layer image as a 
height_field in the original scene, superposed if necessary over a 
pre-existing height_field or other surface.

It is a business that needs close attention but far from impossible and, 
using a paint program in conjunction with a height_field generator, it 
can even make more interesting features.

Thomas


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