POV-Ray : Newsgroups : povray.general : uv mapping Server Time
9 Aug 2024 03:20:32 EDT (-0400)
  uv mapping (Message 1 to 5 of 5)  
From: ryan constantine
Subject: uv mapping
Date: 9 Sep 2000 04:01:55
Message: <39B9EE70.2A50CC3B@yahoo.com>
i tried to 'UVMapper' an obj file i exported from hamapatch, and then
tried to convert it with pose2pov and objuvpov with no luck.  i can't
get the uvmap to look right and i keep getting an error when i run the
pov file that says 'mesh normal index out of range'.  i think it has
something to do with either my cockpit and landing gear bay (which go
into the object) or my separating wall which divides two halves of the
model (used to export each half separately although i'd rather not). 
does anyone have tips for this?  i was using gilles tran's tut on the
subject.  or does someone have an appropriate program and could convert
it for me?  i don't have a uv map.  i was using uvmapper to generate one
and it looked kind of messed up no matter what i tried.  i also tried to
export part of my model from hamapatch (without the cockpit, the landing
gear bay and the center wall), make a uvmap with uvmapper, save it,
export the whole model again from hamapatch and then put the saved uvmap
onto the whole model in uvmapper (because i don't need the inside
textured} but it wouldn't let me.  it said the uv information didn't
match.  bummer.  if i had my dream cylindrical camera i keep bringing
up, i wouldn't have to go through all this.

by the way, in uvmapper, when you set the uvmap size, are you just
setting the image size or does that information get passed to the pov
and/or inc files?


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From: Gilles Tran
Subject: Re: uv mapping
Date: 9 Sep 2000 05:17:20
Message: <39B9FF93.71F90177@inapg.inra.fr>
ryan constantine wrote:

> i tried to 'UVMapper' an obj file i exported from hamapatch, and then
> tried to convert it with pose2pov and objuvpov with no luck.  i can't
> get the uvmap to look right and i keep getting an error when i run the
> pov file that says 'mesh normal index out of range'.

Perhaps you could try the latest version of 3DWIN, which seems to be quite
reliable when converting to mesh2 (no crash so far).

> i don't have a uv map.  i was using uvmapper to generate one
> and it looked kind of messed up no matter what i tried.

What do you mean by "messed up" ? I've seen a lot a weird things there...
I've no experience with Hamapatch though.
If you mean that the model looks right but that the different parts are
superposed, there's nothing you can do but exporting and mapping the parts
separately, using the most appropriate mapping model (box, sphere, cylinder
etc.) for each part. One very important thing is to save both the uvmap AND
the obj model in uvmapper, otherwise the uv info is not added to the obj.


> by the way, in uvmapper, when you set the uvmap size, are you just
> setting the image size or does that information get passed to the pov
> and/or inc files?

AFAIK, the uvmap size and ratio does not affect the way it's shown on the
object (the coordinates are not absolute but relative to the map width and
height). Note that I know this just from observation (I often scale down the
maps for testing purposes) and the reality could be more complex.
I hope this helps
G.


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From: ryan constantine
Subject: Re: uv mapping
Date: 9 Sep 2000 06:31:48
Message: <39BA0E46.29DFC5D8@yahoo.com>
> What do you mean by "messed up" ? I've seen a lot a weird things there...

overlapped edges of triangles.  

> I've no experience with Hamapatch though.
> If you mean that the model looks right but that the different parts are
> superposed, there's nothing you can do but exporting and mapping the parts
> separately, using the most appropriate mapping model (box, sphere, cylinder
> etc.) for each part. 

i'm really trying for a solid mesh.  i need to cut a few things out
later.  but if worse comes to worse, i'll rebuild the parts with the
cutouts built in.

> AFAIK, the uvmap size and ratio does not affect the way it's shown on the
> object (the coordinates are not absolute but relative to the map width and
> height). Note that I know this just from observation (I often scale down the
> maps for testing purposes) and the reality could be more complex.
> I hope this helps

me too.


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From: Gilles Tran
Subject: Re: uv mapping
Date: 9 Sep 2000 07:08:49
Message: <39BA19B6.D5FE2D66@inapg.inra.fr>
ryan constantine wrote:

> i'm really trying for a solid mesh.  i need to cut a few things out
> later.  but if worse comes to worse, i'll rebuild the parts with the
> cutouts built in.
>

Actually this is not such a problem I think. Many models I've found on the Net or
elsewhere are made up of individual parts (meshes) that are independently
textured, possibly because it's more practical that way. Unless you have a 3D
painting tool that lets you manipulate the object like you'd do in real life,
you'll have to decide the best mapping for each part : the wings could use a
simple box uv mapping, the hull could use a cylindrical uv mapping and so on. The
cylindrical camera you've been dreaming about could be helpful in some cases, but
could be hard to manage in many others, because of the distortions.
G.


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From: ryan constantine
Subject: Re: uv mapping
Date: 9 Sep 2000 15:52:43
Message: <39BA9513.4BAAE484@yahoo.com>
> The
> cylindrical camera you've been dreaming about could be helpful in some cases, but
> could be hard to manage in many others, because of the distortions.

i recently took the rear half of my fuselage, put a spherical camera
inside and took a 2:1 pic of it after texturing each triangle by hand
into logical square-like groups.  then, i fixed the colors so they were
solid and not shaded and then used the image as a material map, mapped
spherically with the center in the same place as the camera was.  it
worked pretty good except for the lines i had drawn between each section
came out really bad.  the image size i had used was 2000 by 1000 and
while you couldn't see the jaggy edges of the squares, the lines in
between the squares were really jaggy.  i could increase the rendered
2:1 pic's resolution, but then i figured this trick couldn't be done
with the front of the fuselage due to my cockpit.

i think what i will do is either build-in the cutouts i need, or split
my model into parts as you suggest, but close each off so each can be
solid.  i know you don't know hamapatch gilles, but if any other readers
out there do, is 4 the largest subdivision you can get for an export? 
spatch gives up to 96, but can't export obj.  also, regarding 3dwin,
what do smooth angle and edge angle mean?  i'm getting pinched areas
where patches (now triangles in the conversion) meet.  i assume size
value is the scale.  hey gilles, you mentioned the new version of 3dwin,
doesn't it cost money now?  or could the free version be enough for what
i need?

thanks for your help.  sometimes i wish i didn't tackle the xwing as my
first project because the more i learn, the more i want to change it.  i
just can't leave it alone.  but if my current efforts work, i'll have a
version 2 sooner than i thought.  and r2d2 needs some minor changes
since i found better pictures shortly after i finished him.  oh well.


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