POV-Ray : Newsgroups : povray.documentation.inbuilt : Add a non-origin sphere example to Scale : Re: Add a non-origin sphere example to Scale Server Time
20 Apr 2024 00:26:01 EDT (-0400)
  Re: Add a non-origin sphere example to Scale  
From: Christoph Hormann
Date: 26 Apr 2004 12:55:01
Message: <c6jeqs$7ss$1@chho.imagico.de>
Phil Cook wrote:
> Someone else has just been caught out by 'moving' objects when using 
> scale, I was wondering if adding a non-origin sphere to the example 
> would highlight this, perhaps:
> 
> Scale also alters the vector components of an object
> 
> For example
> 
>  sphere { <1,1,1>, 1
>   scale 5> // Evaluates as <5,5,5> so uniformly scale
>       // by 5 in every direction.
>       // but also multiplies the vector location
>     // resulting in a translation to <5,5,5>
>  }

See "2.2.7.2 Transformation Order" - without such a complete example but 
well explained IMO.

Apart from that your explanation is wrong.  A transform does not 
transform the radius and center of the sphere but the whole object.  In 
fact POV-Ray does not even transform the object but transforms the ray 
with the inverse transform - otherwise a lot of shapes could not be 
transformed arbitrarily at all.

Christoph

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