POV-Ray : Newsgroups : povray.binaries.images : Sphere_Sweep Difficulties Server Time
5 Nov 2024 10:20:27 EST (-0500)
  Sphere_Sweep Difficulties (Message 1 to 3 of 3)  
From: How Camp
Subject: Sphere_Sweep Difficulties
Date: 15 Nov 2006 09:54:41
Message: <455b2a31$1@news.povray.org>
I've not used sphere_sweeps much, but perhaps someone can explain why mine 
looks like it does in this image?  I thought I should see a nice smooth 
transition from one sphere to the other...  Granted, I'm working on a small 
scale (as the code below shows), so is this a precision problem?  I've tried 
fiddling around, but I'm not understanding what's happening.

Any comments as to (a) what's wrong, and (b) how to fix this would be 
greatly appreciated.

- How



#version 3.6;
global_settings {assumed_gamma 1.0}
camera { location <2, 1, -0> angle 1.5 look_at <6.1, 0.115, 5>}
background {color rgb 1}
light_source { <-30, 30, -30> color rgb <1, 1, 1> }

sphere_sweep {
  cubic_spline
  7,
  <0.22, 0.18, -0.000>, 0.00501
  <0.22, 0.17, -0.001>, 0.00452
  <0.22, 0.16, -0.002>, 0.00401
  <0.22, 0.15, -0.002>, 0.00302
  <0.22, 0.14, -0.001>, 0.00301
  <0.22, 0.13, -0.001>, 0.00302
  <0.22, 0.12, -0.000>, 0.00501
  texture{pigment{color rgb <1,0,0>}}
  translate <-0.02,0,-0.005>
  translate <4.77,0.2,3.64999>
}


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Attachments:
Download 'ssweep.png' (10 KB)

Preview of image 'ssweep.png'
ssweep.png


 

From: nemesis
Subject: Re: Sphere_Sweep Difficulties
Date: 15 Nov 2006 11:15:00
Message: <web.455b3ca1330d4cfee88ade10@news.povray.org>
why's everything so small?  camera angle of 1.5?!

perhaps that's the problem:  you're getting low accuracy from getting into
microscopic realm... also, i heard sphere_sweeps have issues when they are
very big.  perhaps they also have problems when very small...


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From: How Camp
Subject: Re: Sphere_Sweep Difficulties
Date: 15 Nov 2006 12:10:49
Message: <455b4a19$1@news.povray.org>
"nemesis" <nam### [at] gmailcom> wrote in message 
news:web.455b3ca1330d4cfee88ade10@news.povray.org...
> why's everything so small?  camera angle of 1.5?!
>
> perhaps that's the problem:  you're getting low accuracy from getting into
> microscopic realm... also, i heard sphere_sweeps have issues when they are
> very big.  perhaps they also have problems when very small...


Hrmph.  You're right, of course.  I got carried away in my scene, forgot I 
had zoomed in to look at some detail or other, thought how neat it would be 
to put a sphere_sweep riiiight here... and it's no wonder I've got weird 
problems.  Once I backed out and made my shape correctly, things settled 
down.

Thanks for the reality check, Nemesis!

- Humble How


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