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POV-Ray : Newsgroups : povray.newusers : UV_vectors.What is it?		Server Time 28 Apr 2024 22:25:27 EDT (-0400)

From: LanuHum
Subject: UV_vectors.What is it?
Date: 29 Jul 2013 13:25:01
Message: <web.51f6a2bcf78c8f867a3e03fe0@news.povray.org>

Hi!
My problem - uv vectors in bicubic patch.
There are vertices, there are pixel on the picture. How to calculate a
UV-vector?
Why it is difficult? Point 3D(x,y,z) in object == point 2D(x,y) in picture.What
vectors?

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From: Le Forgeron
Subject: Re: UV_vectors.What is it?
Date: 29 Jul 2013 15:08:26
Message: <51f6bdaa$1@news.povray.org>

Le 29/07/2013 19:23, LanuHum nous fit lire :
> Hi!
> My problem - uv vectors in bicubic patch.
> There are vertices, there are pixel on the picture. How to calculate a
> UV-vector?
> Why it is difficult? Point 3D(x,y,z) in object == point 2D(x,y) in picture.What
> vectors?

Have you read :

> http://wiki.povray.org/content/Documentation:Tutorial_Section_3#Bicubic_Patch_Object

A bicubic patch is a grid (uv) warped in the 3D (x,y,z).
The UV coordinates of the grid are not specified in the scene (but the
size of the grid can be changed).

> http://wiki.povray.org/content/Reference:UV_Mapping

The main problem with bicubic patch is the computation of nodes points
and control points (which push/pull intermediates points).

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From: LanuHum
Subject: Re: UV_vectors.What is it?
Date: 30 Jul 2013 12:05:01
Message: <web.51f7e40453dca86a7a3e03fe0@news.povray.org>

Le_Forgeron <jgr### [at] freefr> wrote:
> Le 29/07/2013 19:23, LanuHum nous fit lire :
> > Hi!
> > My problem - uv vectors in bicubic patch.
> > There are vertices, there are pixel on the picture. How to calculate a
> > UV-vector?
> > Why it is difficult? Point 3D(x,y,z) in object == point 2D(x,y) in picture.What
> > vectors?
>
> Have you read :
>
> >
http://wiki.povray.org/content/Documentation:Tutorial_Section_3#Bicubic_Patch_Object
>
> A bicubic patch is a grid (uv) warped in the 3D (x,y,z).
> The UV coordinates of the grid are not specified in the scene (but the
> size of the grid can be changed).
>
> > http://wiki.povray.org/content/Reference:UV_Mapping
>
> The main problem with bicubic patch is the computation of nodes points
> and control points (which push/pull intermediates points).

Thanks!

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From: LanuHum
Subject: Re: UV_vectors.What is it?
Date: 8 Aug 2013 15:55:00
Message: <web.5203f71a53dca86a7a3e03fe0@news.povray.org>

"LanuHum" <Lan### [at] yandexru> wrote:

> >
> > The main problem with bicubic patch is the computation of nodes points
> > and control points (which push/pull intermediates points).

In blender-no problems
I can receive coordinates of all points....
Thanks!

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