On Thu, 15 May 2003 20:05:22 +0200, Christoph Hormann <chr### [at] gmxde>
wrote:
>#declare fn_rotated=
>  function { 
>    fn_original(
>      x*cos(Angle)+y*sin(Angle), 
>      -x*sin(Angle)+y*cos(Angle), z
>    ) 
>  }
>
>therefore twisting would be something like:
>
>#declare fn_twisted=
>  function { 
>    fn_original(
>      x*cos(AngleFactor*z)+y*sin(AngleFactor*z), 
>      -x*sin(AngleFactor*z)+y*cos(AngleFactor*z), z
>    ) 
>  }

writing both as:

#declare fn_rotated=
  function(x,y,z,Angle) { 
    ...
  }

#declare fn_twisted=
  function(x,y,z,AngleFactor) { 
    ...
  }

gives variable deforming along axis but calculations will be probably slower.

ABX

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On Thu, 15 May 2003 19:17:00 +0200, ABX <abx### [at] abxartpl> wrote:
> are
> you asking if it is possible to apply "warping" deformations to mesh builded
> with method described in this thread?

http://news.povray.org/povray.binaries.images/13547/91145/chevy1.jpg

ABX

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phi7cv4dm0mqr40t8t5kb0klp3nfml9fta@4ax.com...

> I do not understand. Are you asking if it is possible to apply more
complicated
> "warping" deformations to functions and create isosurface (like I did in
> http://news.povray.org/povray.binaries.animations/23891/167475/wip.mpg )

That's it! (I just knew that there was a reason why I was asking you...).
I'll have a look at the functions Christoph and you provided. Many thanks to
both.

G.

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"Gilles Tran" <tra### [at] inapginrafr> wrote in
news:3ec3c92a$1@news.povray.org: 

...
> Just wondering: is it possible to "warp" a rounded box (bending,
> shearing, twisting...) or another shape? Simple surface displacement
> can be done using the formula above, but I've not been able to create
> more drastic deformations.

The shape in this animation;

http://news.povray.org/povray.binaries.animations/31252/
http://home.no/t-o-k/povray/Quadrivariate_NURBS_Deformation.m1v
(The one on my homepage is of better quality.)

- does not have to be a "cube", it can be any mesh shape you want.

So a lot of different mesh deformations are possible by using
vector valued trivariate NURBS.


Tor Olav

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