POV-Ray : Newsgroups : povray.general : uv_mapping example for lathe Server Time
3 Aug 2024 04:21:04 EDT (-0400)
  uv_mapping example for lathe (Message 1 to 3 of 3)  
From: jsn
Subject: uv_mapping example for lathe
Date: 24 May 2004 13:50:01
Message: <web.40b23521d2f0ed5795a5700@news.povray.org>
Could someone provide a sample of uv mapping of a simple lather object?  I
cannot seem to get this to work properly, the image seems too big and I
cannot scale it.


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From: jsn
Subject: Re: uv_mapping example for lathe
Date: 24 May 2004 17:25:00
Message: <web.40b2678d21fcf82195a5700@news.povray.org>
I guess I wasn't very clear earlier about uv mapping with the lathe object.
I think the documentation is lacking when it comes to examples of how to do
UV mapping for the lathe and SOR objects.  It is entirely unclear how to
scale the images and how to specify specific areas on the objects.  For
example, Say I wanted to paste my companies logo on a Lathe coffee cup
object.  Right now without direction from the documentation, this isn't
very clear.  I can apply the image, but I cannot scale it or place it very
specifically.  Currently, the png logo image completely wraps the lathe
object.  I would like to size it and place it 90 degrees from the cup
handle.

So, this is the type of example I am looking for.  The documentation or
example files should include this type of operation.

Jeff


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From: povray
Subject: Re: uv_mapping example for lathe
Date: 1 Jun 2004 13:41:30
Message: <40bca087.4994586@localhost>
On Mon, 24 May 2004 17:22:21 EDT, "jsn" <jni### [at] orblmgov> wrote:

>I guess I wasn't very clear earlier about uv mapping with the lathe object.
>I think the documentation is lacking when it comes to examples of how to do
>UV mapping for the lathe and SOR objects. 

Docs could be clearer, yes.  Too bad I suck at docs or I'de throw
something together for the pov-team to use.  Just experiment with
an easily-recognizable image and you'll get the hang of it.
To rotate an image around a lathe, translate the image in the
x direction.  The total uv width (and height) of the image is
always 1 (before translation. etc.) so translate in 0.1
increments and re-render to see what is going on.  In the uv-
coordinate space, X and Y are the coordinates you are wanting
to play with. translating or scaling Z will have no effect.


>example, Say I wanted to paste my companies logo on a Lathe coffee cup
>object.

Ok: if you are using UV_mapping just to put a logo on a coffee
cup then you can use an easier way.  If you use a cylindircal
mapping on the image map, life will be easier.  The "map_once"
option plus careful scaling and translation will get that logo
where you want it on the cup.  The only bad side to useing a
cylindrical map is that the logo will also appear on the inside
of the cup.  Careful camera placement is most likely enough
to fix that.  :)



-- 
to all the companies who wait until a large user base becomes
dependant on their freeware, then shafting said happy campers with
mandatory payment for continued usage. I spit on your grave.


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