POV-Ray : Newsgroups : povray.binaries.animations : Circle of latitude Server Time: 12 Dec 2018 21:48:46 GMT
  Circle of latitude (Message 1 to 8 of 8)  
From: Mike Horvath
Subject: Circle of latitude
Date: 18 Jul 2018 00:49:57
Message: <5b4e8eb5@news.povray.org>
A very simple animation, but it took me most of the day.


Mike


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Download 'animation1.gif' (1469 KB)

Preview of image 'animation1.gif'
animation1.gif


 

From: dick balaska
Subject: Re: Circle of latitude
Date: 18 Jul 2018 02:31:35
Message: <5b4ea687$1@news.povray.org>
On 07/17/2018 08:51 PM, Mike Horvath wrote:
> A very simple animation, but it took me most of the day.
> 
> 
> Mike

That's awesome.  I'm impressed with the image mapping.
(Another idea to steal for my space scene ;) )

-- 
dik
Rendered 328976 of 330000 (99%)


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From: Mike Horvath
Subject: Re: Circle of latitude
Date: 20 Jul 2018 00:27:39
Message: <5b512c7b$1@news.povray.org>
On 7/17/2018 10:31 PM, dick balaska wrote:
> On 07/17/2018 08:51 PM, Mike Horvath wrote:
>> A very simple animation, but it took me most of the day.
>>
>>
>> Mike
> 
> That's awesome.  I'm impressed with the image mapping.
> (Another idea to steal for my space scene ;) )
> 

Thanks! I'm working on doing the same with an ellipsoid, but have run 
into some problems:

1. How do I map the texture to the ellipsoid? Do I apply the texture 
before shrinking the sphere or after? (I *think* I should do the latter.)
2. Should I use geodetic latitude, geocentric latitude or reduced 
latitude? (In this case I *think* the first one is the one to use.)


Mike


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From: Mike Horvath
Subject: Re: Circle of latitude
Date: 20 Jul 2018 00:33:18
Message: <5b512dce$1@news.povray.org>
The first image uses a geodetic latitude of 60 degrees N for the orange 
ring, and features the texture applied *after* turning the sphere into 
an ellipsoid instead of *before*.

The second image is simply a sphere squashed vertically.


Mike


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Attachments:
Download 'cone_of_latitude_oblate_mono_a06.png' (37 KB)
Download 'cone_of_latitude_oblate_mono_b06.png' (39 KB)

Preview of image 'cone_of_latitude_oblate_mono_a06.png'
cone_of_latitude_oblate_mono_a06.png

Preview of image 'cone_of_latitude_oblate_mono_b06.png'
cone_of_latitude_oblate_mono_b06.png


 

From: Bald Eagle
Subject: Re: Circle of latitude
Date: 20 Jul 2018 01:00:00
Message: <web.5b51333ddd67224e458c7afe0@news.povray.org>
I'm concerned about the position of the ring there.   How are you manipulating
the torus and the sphere?  Separately, or as a union?

Figure b sits way higher than on a.


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comparison.jpg


 

From: Mike Horvath
Subject: Re: Circle of latitude
Date: 20 Jul 2018 01:16:01
Message: <5b5137d1$1@news.povray.org>
On 7/19/2018 8:56 PM, Bald Eagle wrote:
> I'm concerned about the position of the ring there.   How are you manipulating
> the torus and the sphere?  Separately, or as a union?
> 
> Figure b sits way higher than on a.
> 

Separately. Note that it's common for geodetic latitude (left) and 
reduced latitude (right) to be different for the same location(s) on Earth.


Mike


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From: Mike Horvath
Subject: Re: Circle of latitude
Date: 24 Jul 2018 22:38:07
Message: <5b57aa4f@news.povray.org>
A followup, showing the effect of ellipsoidification. Took a bit longer 
to design than the first image.


Mike


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Attachments:
Download 'cone_of_latitude_ellipsoid.gif' (1911 KB)

Preview of image 'cone_of_latitude_ellipsoid.gif'
cone_of_latitude_ellipsoid.gif


 

From: Mike Horvath
Subject: Re: Circle of latitude
Date: 24 Jul 2018 22:56:34
Message: <5b57aea2$1@news.povray.org>
On 7/24/2018 6:38 PM, Mike Horvath wrote:
> A followup, showing the effect of ellipsoidification. Took a bit longer 
> to design than the first image.
> 
> 
> Mike

Note that the globe is simply squished vertically. The lines of latitude 
are not in nice regular intervals of 15 degrees, going by either 
geocentric or geodetic latitude. I may fix this at some later point if I 
can figure out how.


Mike


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