Hello. I wonder if there is any way to modify or transform the box or sphere
inside the contain_by statement. Often when making isosurfaces, I see the
outline of the contained_by object. In fact, are those the only two legal
contained_by objects, and why can't you rotate or otherwise modify what's
inside the statement?
For example, this doesn't work:
contained_by {box <-X, -X, -X>, <X, X, X> rotate 90}
nor does this: {{box <-X, -X, -X>, <X, X, X> rotate 90}  }

Are there any ways to modify the box or sphere and why can't other shapes be
used?
Thanks much,
Dennis

--
dhm### [at] mediaonenet
www.casdn.neu.edu/~dmiller

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I'm not sure about this, but I have the impression that the contained_by
object has nothing (or at least very little) to do with the actual sphere or
box primitives. The syntax is just the same for convenience, but internally
it's not a primitive, but just ranges that limit the calculations to certain
limits (isosurfaces must be calculated inside certain limits; you can't have
infinite isosurfaces).

-- 
#macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
],13),8)-3,10>#end blob{N(array[6]{11117333955,
7382340,3358,3900569407,970,4254934330},0)}//                     - Warp -

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Warp wrote:

> limits (isosurfaces must be calculated inside certain limits; you can't have
> infinite isosurfaces).

Overflow problems ?

-- 
Ken Tyler

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In article <3B59EC61.3CF0C0C4@pacbell.net> , Ken <tyl### [at] pacbellnet>  
wrote:

>> limits (isosurfaces must be calculated inside certain limits; you can't have
>> infinite isosurfaces).
>
> Overflow problems ?

No.  Actually there can be (semi-)infinite isosurfaces. As you know, the
POV-Ray scene space is finite, just make the container big enough to fill
the whole scene.  The actual problem is that the bigger the container the
more calculations are needed unless the accuracy parameter is adjusted.


     Thorsten


____________________________________________________
Thorsten Froehlich, Duisburg, Germany
e-mail: tho### [at] trfde

Visit POV-Ray on the web: http://mac.povray.org

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Well to clarify, the shape of the contained_by object is very clear (a box
or a sphere) in some points of the animations that I am working on. I'm
trying to find out if there are any ways to modify those shapes, which are
like a frame for the isosurface. Why you can't rotate or scale the
contained-by object independent of the isosurface itself or for that matter,
use other types of contained by shapes (cylinder, cone, etc.).
Anyone know?
thanks,
Dennis
"Thorsten Froehlich" <tho### [at] trfde> wrote in message
news:3b59f90b@news.povray.org...
> In article <3B59EC61.3CF0C0C4@pacbell.net> , Ken <tyl### [at] pacbellnet>
> wrote:
>
> >> limits (isosurfaces must be calculated inside certain limits; you can't
have
> >> infinite isosurfaces).
> >
> > Overflow problems ?
>
> No.  Actually there can be (semi-)infinite isosurfaces. As you know, the
> POV-Ray scene space is finite, just make the container big enough to fill
> the whole scene.  The actual problem is that the bigger the container the
> more calculations are needed unless the accuracy parameter is adjusted.
>
>
>      Thorsten
>
>
> ____________________________________________________
> Thorsten Froehlich, Duisburg, Germany
> e-mail: tho### [at] trfde
>
> Visit POV-Ray on the web: http://mac.povray.org

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Dennis Milller <dhm### [at] mediaonenet> wrote:
: Why you can't rotate or scale the
: contained-by object independent of the isosurface itself or for that matter,
: use other types of contained by shapes (cylinder, cone, etc.).
: Anyone know?

  I already explained the most probable reason.
  The contained_by object is not an object at all. It's just a set of limits
for the isosurface calculation function. Thus you can't transform it as if
it was a regular primitive (because it isn't).
  The syntax for the contained_by object is the same as for a sphere or a
box, but only for convenience.

-- 
#macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
],13),8)-3,10>#end blob{N(array[6]{11117333955,
7382340,3358,3900569407,970,4254934330},0)}//                     - Warp -

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In article <3b5a415a@news.povray.org> , "Dennis Milller" 
<dhm### [at] mediaonenet> wrote:

> Well to clarify, the shape of the contained_by object is very clear (a box
> or a sphere) in some points of the animations that I am working on. I'm
> trying to find out if there are any ways to modify those shapes, which are
> like a frame for the isosurface. Why you can't rotate or scale the
> contained-by object independent of the isosurface itself or for that matter,
> use other types of contained by shapes (cylinder, cone, etc.).

Well, be aware that scaling or rotating an isosurface object does work on
its container only, not the isosurface function (because its easier to
implement).  So you just have to put the transformations in the isosurface
block, not the contained_by block.


    Thorsten


____________________________________________________
Thorsten Froehlich, Duisburg, Germany
e-mail: tho### [at] trfde

Visit POV-Ray on the web: http://mac.povray.org

Post a reply to this message

Thorsten Froehlich <tho### [at] trfde> wrote:
: Well, be aware that scaling or rotating an isosurface object does work on
: its container only, not the isosurface function (because its easier to
: implement).  So you just have to put the transformations in the isosurface
: block, not the contained_by block.

  This makes no sense, and it doesn't work that way, I just tested.
  If you scale (for example non-uniformly) an isosurface, the whole object
is scaled, not the container object only. That is, if you scale non-uniformly,
the isosurface gets squeezed as well, not the container only. As it should,
as it's logical.

-- 
#macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
],13),8)-3,10>#end blob{N(array[6]{11117333955,
7382340,3358,3900569407,970,4254934330},0)}//                     - Warp -

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In article <3b5abcb7@news.povray.org> , Warp <war### [at] tagpovrayorg>  wrote:

>   This makes no sense, and it doesn't work that way, I just tested.

It used to work this way in MegaPOV, didn't it?  I remember there was some
problem with containers...

> As it should, as it's logical.

I never disputed that the behavior is illogical.


    Thorsten


____________________________________________________
Thorsten Froehlich, Duisburg, Germany
e-mail: tho### [at] trfde

Visit POV-Ray on the web: http://mac.povray.org

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I may have misunderstood your problem, but couldn't you intersect the
isosurface with your desired primitive ie cone, cylinder etc? Then you could
apply all your rotates and scales to the intersected primitive.

Andy

"Dennis Milller" <dhm### [at] mediaonenet> wrote in message
news:3b5a415a@news.povray.org...
> Well to clarify, the shape of the contained_by object is very clear (a box
> or a sphere) in some points of the animations that I am working on. I'm
> trying to find out if there are any ways to modify those shapes, which are
> like a frame for the isosurface. Why you can't rotate or scale the
> contained-by object independent of the isosurface itself or for that
matter,
> use other types of contained by shapes (cylinder, cone, etc.).
> Anyone know?
> thanks,
> Dennis

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