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30 Jul 2024 18:21:56 EDT (-0400)
  Quicker substitute for parametric object (Message 1 to 7 of 7)  
From: SharkD
Subject: Quicker substitute for parametric object
Date: 28 Jun 2008 13:35:01
Message: <web.4866763581617d2ffa138a830@news.povray.org>
I've created the following parametric object:

#local Wid = 1/2;
#local Hgh = 1/2;
#local Thk = 1/32;
#local Trn = 256/Hgh/64;
parametric
{
 function { (1/2 - v * Thk) * cos(Trn * u * 2 * pi) },
 function { 1 * u },
 function { (1/2 - v * Thk) * sin(Trn * u * 2 * pi) }
 <0,0>, <1,1>
 contained_by { box {<-1/2,0,-1/2,>, <1/2,1,1/2,>} }
 max_gradient 1/1000
 accuracy 1/1000
 precompute 20 x,y,z
 scale <Wid,Hgh,Wid,>
}

I was wondering if there were a quicker alternative that I hadn't thought of?

Thanks!

-Mike


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From: SharkD
Subject: Re: Quicker substitute for parametric object
Date: 28 Jun 2008 14:15:00
Message: <web.48667e8e20f02e63fa138a830@news.povray.org>
I just tested the Helix and Helix_1 shapes in "shapes1.inc", and the result has
a very weird shape, especially when viewed from the top. Is this the way it's
supposed to look? It doesn't look much like a helix.

-Mike


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From: Warp
Subject: Re: Quicker substitute for parametric object
Date: 28 Jun 2008 15:12:42
Message: <48668d2a@news.povray.org>
SharkD <nomail@nomail> wrote:
> I was wondering if there were a quicker alternative that I hadn't thought of?

  You could always try to create a triangle mesh from those functions.
The code will be quite complicated, but the result will render extremely
fast.

-- 
                                                          - Warp


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From: SharkD
Subject: Re: Quicker substitute for parametric object
Date: 28 Jun 2008 15:40:01
Message: <web.4866927720f02e63fa138a830@news.povray.org>
Warp <war### [at] tagpovrayorg> wrote:
> SharkD <nomail@nomail> wrote:
> > I was wondering if there were a quicker alternative that I hadn't thought of?
>
>   You could always try to create a triangle mesh from those functions.
> The code will be quite complicated, but the result will render extremely
> fast.
>
> --
>                                                           - Warp

Thanks, that's a good idea. I was hoping to avoid doing this though, as it's a
bit more involved.

-Mike


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From: Mike Williams
Subject: Re: Quicker substitute for parametric object
Date: 28 Jun 2008 16:04:47
Message: <PKL4wyAPgpZIFwD+@econym.demon.co.uk>
Wasn't it SharkD who wrote:
>Warp <war### [at] tagpovrayorg> wrote:
>> SharkD <nomail@nomail> wrote:
>> > I was wondering if there were a quicker alternative that I hadn't 
>> >thought of?
>>
>>   You could always try to create a triangle mesh from those functions.
>> The code will be quite complicated, but the result will render extremely
>> fast.
>>
>> --
>>                                                           - Warp
>
>Thanks, that's a good idea. I was hoping to avoid doing this though, as it's a
>bit more involved.

There's a macro by Ingo Janssen that creates a mesh2 of smooth triangles 
from a set of parametric equations. It's an awful lot faster than 
parametric isosurfaces, and you can save the mesh to a file.

See: http://www.econym.demon.co.uk/isotut/param.htm

-- 
Mike Williams
Gentleman of Leisure


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From: SharkD
Subject: Re: Quicker substitute for parametric object
Date: 28 Jun 2008 17:40:00
Message: <web.4866af0320f02e63fa138a830@news.povray.org>
Mike Williams <nos### [at] econymdemoncouk> wrote:
> There's a macro by Ingo Janssen that creates a mesh2 of smooth triangles
> from a set of parametric equations. It's an awful lot faster than
> parametric isosurfaces, and you can save the mesh to a file.
>
> See: http://www.econym.demon.co.uk/isotut/param.htm
>
> --
> Mike Williams
> Gentleman of Leisure

Wow! I completely forgot about that. Thanks for the tip!

Anyway, I ended up doing the mesh by hand. It wasn't that difficult after all.

-Mike


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From: helge h
Subject: Re: Quicker substitute for parametric object
Date: 7 Jul 2008 07:50:01
Message: <web.4872028e20f02e633ca1592f0@news.povray.org>
Mike Williams <nos### [at] econymdemoncouk> wrote:
> Wasn't it SharkD who wrote:
> >Warp <war### [at] tagpovrayorg> wrote:
> >> SharkD <nomail@nomail> wrote:
> >> > I was wondering if there were a quicker alternative that I hadn't
> >> >thought of?
> >>
> >>   You could always try to create a triangle mesh from those functions.
> >> The code will be quite complicated, but the result will render extremely
> >> fast.
> >>
> >> --
> >>                                                           - Warp
> >
> >Thanks, that's a good idea. I was hoping to avoid doing this though, as it's a
> >bit more involved.
>
> There's a macro by Ingo Janssen that creates a mesh2 of smooth triangles
> from a set of parametric equations. It's an awful lot faster than
> parametric isosurfaces, and you can save the mesh to a file.
>
> See: http://www.econym.demon.co.uk/isotut/param.htm
>
> --
> Mike Williams
> Gentleman of Leisure

The link on that page doesn't work anymore, but I found the files here:
http://code.google.com/p/mmgm/

H


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