"J. Grimbert" wrote:

> Someone recently post an image with an image with two broken blobs
> (I'm unable to see the thread).
>
> I think I have found the origin of the bug.
>
> In get_element_bounding_sphere from blob.c, if an element has
> any transformation, the bounding sphere is also transformed.
>
> ... 8< ...Snip !
>
> The bug nature is odd:
> With only rotate, it is ok
> With only scale (uniform or not), it is ok
> With a mix of uniform scale and rotate, it is ok
> With a mix of non-uniform scale and rotate, it MAY be ok or NOT, according to
> the parameters
> (mainly of the transformations)

Thank you very much Grimbert for looking into
this problem.

I too found that the defects appeared when doing
some combinations of non uniform scaling and
rotations.

(This problem has been BUGGING me some time now)

And to any programming TAG members (E.g. Chris ?):

Should this problem be discussed further in
poray.general or can this now be considered to
be a bug ?


Tor Olav
--
mailto:tor### [at] hotmailcom
http://www.crosswinds.net/~tok/tokrays.html

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Tor Olav Kristensen wrote:

> > ... 8< ...Snip !
>
> Should this problem be discussed further in
> poray.general or can this now be considered to
> be a bug ?

I'm not sure why this message ended up in povray.general
(I only replied to J. Grimbert's post in povray.binaries.images.)

Is this because of a "follow-up" setting that Grimbert applied
to his message ?

If so: How can that be done in Netscape ?

Tor Olav
--
mailto:tor### [at] hotmailcom
http://www.crosswinds.net/~tok/tokrays.html

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Tor Olav Kristensen wrote:
> 
> "J. Grimbert" wrote:
> 
> >
> > The bug nature is odd:
> > With only rotate, it is ok
> > With only scale (uniform or not), it is ok
> > With a mix of uniform scale and rotate, it is ok
> > With a mix of non-uniform scale and rotate, it MAY be ok or NOT, according to
> > the parameters
> > (mainly of the transformations)
> 
> Thank you very much Grimbert for looking into
> this problem.
> 
> I too found that the defects appeared when doing
> some combinations of non uniform scaling and
> rotations.
> 
> (This problem has been BUGGING me some time now)
> 
> And to any programming TAG members (E.g. Chris ?):
> 
> Should this problem be discussed further in
> poray.general or can this now be considered to
> be a bug ?

I am not a TAG member, but hereafter is my bugfix
but we need a consensus before being allowed to post in bug-report.



--- blob.c.old  Thu Sep  7 18:41:28 2000
+++ blob.c      Thu Sep  7 18:44:55 2000
@@ -2468,7 +2468,8 @@
 static void get_element_bounding_sphere(BLOB_ELEMENT *Element, VECTOR Center,
DBL *Radius2)
 {
   DBL r, r2 = 0.0;
-  VECTOR C, H;
+  VECTOR C;
+  BBOX local_BBox;
 
   switch (Element->Type)
   {
@@ -2514,12 +2515,10 @@
 
     MTransPoint(C, C, Element->Trans);
 
-    Make_Vector(H, r, r, r);
-
-    MTransDirection(H, H, Element->Trans);
-
-    r = max(max(fabs(H[X]), fabs(H[Y])), fabs(H[Z]));
-
+    Make_BBox(local_BBox ,0,0,0,r,r,r);
+    Recompute_BBox(&local_BBox, Element->Trans);
+    r= max(max(fabs(local_BBox.Lengths[X]),fabs(local_BBox.Lengths[Y])),
+               fabs(local_BBox.Lengths[Z]));
     r2 = Sqr(r) + EPSILON;
   }

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Follow-up set to povray.off-topic

Tor Olav Kristensen wrote:
> 
> Tor Olav Kristensen wrote:
> 
> > > ... 8< ...Snip !
> >
> > Should this problem be discussed further in
> > poray.general or can this now be considered to
> > be a bug ?
> 
> I'm not sure why this message ended up in povray.general
> (I only replied to J. Grimbert's post in povray.binaries.images.)
> 
> Is this because of a "follow-up" setting that Grimbert applied
> to his message ?

Yes.

> 
> If so: How can that be done in Netscape ?
> 
Like I did !
In the address sub-panel, where you have the Group:  and other,
simply change the combo of the empty line to Follow-Up and then
fill in the line.

Post a reply to this message

Could someone please tell me in which group the original post of this is?


In article <39B83BD7.105FFC75@online.no> , Tor Olav Kristensen
<tto### [at] onlineno>  wrote:

>
> "J. Grimbert" wrote:
>
>> Someone recently post an image with an image with two broken blobs
>> (I'm unable to see the thread).
>>
>> I think I have found the origin of the bug.
>>
>> In get_element_bounding_sphere from blob.c, if an element has
>> any transformation, the bounding sphere is also transformed.
>>
>> ... 8< ...Snip !
>>
>> The bug nature is odd:
>> With only rotate, it is ok
>> With only scale (uniform or not), it is ok
>> With a mix of uniform scale and rotate, it is ok
>> With a mix of non-uniform scale and rotate, it MAY be ok or NOT, according to
>> the parameters
>> (mainly of the transformations)
>
> Thank you very much Grimbert for looking into
> this problem.
>
> I too found that the defects appeared when doing
> some combinations of non uniform scaling and
> rotations.
>
> (This problem has been BUGGING me some time now)
>
> And to any programming TAG members (E.g. Chris ?):
>
> Should this problem be discussed further in
> poray.general or can this now be considered to
> be a bug ?
>
>
> Tor Olav
> --
> mailto:tor### [at] hotmailcom
> http://www.crosswinds.net/~tok/tokrays.html
>
>



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

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

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Thorsten Froehlich wrote:
> 
> Could someone please tell me in which group the original post of this is?

I'm pretty sure that it was in .binaries.images.

-- 
Ken Tyler - 1400+ POV-Ray, Graphics, 3D Rendering, and Raytracing Links:
http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/

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Subject : Two broken Blobs (Bug ?) (8KB)
Date : 04 September 2000 21:30
From : Tor Olav Kristensen

Kev

Pov-Gallery & Homepage: http://web.libertysurf.co.uk/kevin.ellis

Post a reply to this message

In article <39B9060F.2773BD2C@pacbell.net> , Ken <tyl### [at] pacbellnet>  
wrote:
> I'm pretty sure that it was in .binaries.images.

In article <39b90842@news.povray.org> , "Kevin Ellis"
<kev### [at] libertysurfcouk> wrote:
> Subject : Two broken Blobs (Bug ?) (8KB)
> Date : 04 September 2000 21:30
> From : Tor Olav Kristensen

Thanks!   I have been able to verify the bug and bug fix with a problem that
was on our list of outstanding 3.5 bugs, and I have posted the bug report
and bug fix in povray.bugreports.

Thanks J. Grimbert, you helped getting 3.5 out a few days sooner!


      Thorsten


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

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

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