POV-Ray : Newsgroups : povray.beta-test.binaries : Dokken : Re: Dokken Server Time
2 Mar 2024 22:44:49 EST (-0500)
  Re: Dokken  
From: William F Pokorny
Date: 6 Feb 2017 10:30:53
Message: <589896ad$1@news.povray.org>
On 02/05/2017 03:29 AM, ThH wrote:
> Another old source...
>
> Find it at povray.text.scene-files:
> Different Results Between Versions, Dave Blandston, 07.08.2009
>
> The resulting image doesn't look right to me. What do you think?
>
> Any confirmations?
>

In his post Dave wrote: "This is my source for the Dokken logo. It 
renders fine with version 3.6.1a but does not render correctly with 
version 3.6.2."

On Ubuntu 16.04 linux I get the 'not-right' result with all my versions 
back through 3.5 which includes a version of 3.6.1.

It looks like the root of the problem is the following two values being 
set the same in Dokken.pov:

#local CornerRadius = .02;
#local EdgeRadius = CornerRadius;

which results in zero cylinder-radius, torus-major-radius(1) values in:

#macro BeveledCylinder (Top, Bottom, Radius, EdgeRadius)

    union {
       cylinder {<Top.x, Top.y, Top.z + EdgeRadius>, Bottom, Radius}
       cylinder {Top, Bottom, Radius - EdgeRadius}
       torus {
          Radius - EdgeRadius, EdgeRadius
          rotate 90 * x
          translate <Top.x, Top.y, Top.z + EdgeRadius>
          sturm
       } //torus
    } //union

#end //#macro BeveledCylinder

Using something like:

#local CornerRadius = .02;
#local EdgeRadius = CornerRadius/2;

works OK for me.

Bill P.

(1) - New 3.7.1 spindle torus features allow the minor radius to 
self-intersect for various results, but it's not the right 'fix' here.


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