POV-Ray : Newsgroups : povray.binaries.images : Left vs Right camera views of lathe and prism points for p.d.inbuilt discussion. Server Time
28 Mar 2024 11:33:47 EDT (-0400)
  Left vs Right camera views of lathe and prism points for p.d.inbuilt discussion. (Message 1 to 4 of 4)  
From: William F Pokorny
Subject: Left vs Right camera views of lathe and prism points for p.d.inbuilt discussion.
Date: 4 Jun 2016 09:49:00
Message: <5752dc4c@news.povray.org>
Left vs Right camera views of lathe and prism points image for 
povray.documentation.inbuilt discussion.

Bill P.


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leftvsright.jpg


 

From: Le Forgeron
Subject: Re: Left vs Right camera views of lathe and prism points for p.d.inbuiltdiscussion.
Date: 4 Jun 2016 16:39:33
Message: <57533c85@news.povray.org>
Le 04/06/2016 15:48, William F Pokorny a écrit :
> Left vs Right camera views of lathe and prism points image for
povray.documentation.inbuilt discussion.
> 
> Bill P.

There is a problem with the prism texture : the lower face is of interior_texture for
the counterclockwise prism

In attached pictures: prism was not clipped, lathe was clipped.

And the notion of clockwise is a 3D thing which might still be reworded, something
along: globally, for successive points, compared to the center of all points, when
positive y values decreases, the positive x values increases (?)


right handed system is not only swapping the Z direction, but more often based on Z
being the elevation.


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Attachments:
Download 'lyu.png' (63 KB) Download 'ryu.png' (64 KB) Download 'rzu.png' (66 KB) Download 'lyu.png' (75 KB) Download 'ryu.png' (81 KB) Download 'rzu.png' (85 KB)

Preview of image 'lyu.png'
lyu.png

Preview of image 'ryu.png'
ryu.png

Preview of image 'rzu.png'
rzu.png

Preview of image 'lyu.png'
lyu.png

Preview of image 'ryu.png'
ryu.png

Preview of image 'rzu.png'
rzu.png


 

From: William F Pokorny
Subject: Re: Left vs Right camera views of lathe and prism points forp.d.inbuiltdiscussion.
Date: 4 Jun 2016 19:03:14
Message: <57535e32$1@news.povray.org>
On 06/04/2016 04:39 PM, Le_Forgeron wrote:
> Le 04/06/2016 15:48, William F Pokorny a écrit :
>> Left vs Right camera views of lathe and prism points image for
povray.documentation.inbuilt discussion.
>>
>> Bill P.
>
> There is a problem with the prism texture : the lower face is of interior_texture
for the counterclockwise prism
>
> In attached pictures: prism was not clipped, lathe was clipped.
>
> And the notion of clockwise is a 3D thing which might still be reworded, something
along: globally, for successive points, compared to the center of all points, when
positive y values decreases, the positive x values increases (?)
>
>
> right handed system is not only swapping the Z direction, but more often based on Z
being the elevation.
>

Why are you showing the axis rotations for both xy and xz for the 
prisms? The prism object splines are defined in the xz plane(1) :

http://wiki.povray.org/content/Reference:Prism

"...This is followed by the specified number of 2-D vectors which define 
the shape in the x-z plane."

The prism sweep is in y.

I understand in the right handed system Z is usually treated as up.

Bill P.

(1) - The underlying spline mechanism is perhaps still evaluated inside 
the code as x,y - not sure.


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From: Le Forgeron
Subject: Re: Left vs Right camera views of lathe and prism pointsforp.d.inbuiltdiscussion.
Date: 5 Jun 2016 02:14:00
Message: <5753c328$1@news.povray.org>
Le 05/06/2016 01:03, William F Pokorny a écrit :
> 
> Why are you showing the axis rotations for both xy and xz for the prisms? The prism
object splines are defined in the xz plane(1) :

Because, despite prism being in x-z plane, the notation < a, b > is easily interpreted
as being < x, y >


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