Hello
I'm a bit confused about the UV process in Houdini. I come from a BodyPaint background, where I can bring in a texture of any size, and lay my UV's on top of it.
In Houdini it seems that the texture needs to be contained inside of the Unit Square and then gets stretched onto the appropriate location on the geometry.

Is there anyway to actually view a non square texture in the UV view?

Thanks
Alex

Hi,
Your UVs can live within zero to one or any other value within a repeated tile. Your material just needs to be set to repeat under the texture map options


rob

I guess what I'm asking is if it is possible to view UV's in the UV viewport in a non-square form…I don't need tiling, just a rectangular 3 to 1 aspect ratio on which I want to lay my UV's without having to fit everything in a square…It feels like any other UV layout app can do that…
What am I missing?

Thanks
Alex

Hi,

Forgive my ignorance, do you mean you want 0-1 of U to be three times as wide as 0-1 of V?

I don't think this is possible in the viewport directly, though I can think of tricks that could be used to make a grid display this for you.

I guess I don't understand the desired workflow, please elucidate

Cheers,

Peter B

Here is what I'm trying to do…
I have a surface that has polygons that need to be individually assigned UV's
However these UV's need to be assigned based on an image map that is of 3k resolution, and has an aspect ratio of about 2:1.
The way I work in Bodypaint is that I bring in my texture, and see it in native resolution. I then move my UV polygons around until they match the desired location on the image map.

In Houdini, if I bring in an image map in UV view, it gets mapped to a square. This makes placing my UV's properly quite complicated because the 3k image map is squeezed…

Does this make sense?

Thanks!
Alex

Hi Alex,

OK fair enough. I guess the quick answer is “no” there's no way to adjust the aspect of the UV viewport to do what you want (at least that I am aware of, and I often learn new things about Houdini!).

Just curious, why the non-square aspect for your UV map? Since UV coords are by nature square (assuming 0-1 on each axis).

Cheers,

Peter B

rurik2000
.. . I don't need tiling, just a rectangular 3 to 1 aspect ratio on which I want to lay my UV's without having to fit everything in a square…It feels like any other UV layout app can do that…
What am I missing?

hi ,

if you want a 3:1 ratio on your UVs , you can stretch down your UVs vertically using a TransformUV SOP .

you can do many other things to UVs after you have generated them initially .

press Tab and go into the Material submenu . there you wll find several nodes which deal with UVs .

you are not limited only to those ones in houdini to manipulate UVs .. , but thats a good place to start .



.cheers

p.s.: ive never seen a UV space ( on any application ) displayed in a ratio different from 1:1 ( ?! )

Thanks for the replies.
UV transform is not really what I'm after….

Let me try to explain it like this :
In certain cases you have to work with UV's not based on an optimum layout for the geometry but an optimum layout for the content you are placing on it.
In my case I have a fairly specific 3k image map that has various areas of interest. These areas of interest relate to the way the polygons on my geometry will actually display them.
So for example I have a series of polygons that need to be very concentrated to the left, another series that needs to be looser on the top, and a series of one polygons that need to take in 1 pixel slices on the left.
This is just the nature of the image map and of the actual surface.

In Bodypaint 3d, the workflow is based on the image map. So if I bring in a 3k image, it will show me my UV space relative to this image, since this image is being mapped to the entire geometry.
I'm sure that what is really happening is that the UV's are in fact just being displayed like that for convenience, but then being squeezed back into the typical unit square space.

However the possibility of working within the 3k domain is extremely handy, because I can, for example, export my UV outline to Photoshop and check that, to the pixel, my Uv's match the specific parts of the image map I'm trying to match.

Doing this in 0 to 1 space is the right thing to do, but being stuck to working visually in the 0 to 1 space is not convenient in this case at all….My reference image map is being squeezed to fit, and accurately placing my Uv's is made much more difficult…

Hope this makes any kind of sense…

Thanks
Alex

almost there

ok , i could be wrong , but here is how i see the UV ‘world’ :

~( 2D Edition )~

- an Origin ( 0, 0 ) –{ Birth }
- an End ( 1, 1 ) –{ Death }
- distances in any direction are the same in the other one –{ Laws of Physics }
- if you go beyond the End ( eg: 1.1, 2.3 ) you should get what you Believe :

• a- Repeat –{ Reincarnation }
  b- Streak –{ Annihilation }
  c- Decal –{ Eternal Paradise / Hell }
  
  if we agree with above points ,
  now let speak shortly ( not that i know to much in reality ) about textures and polygons :
  
  - a texture ( no mater its base / height ratio ) will fit itself into a ratio of 1:1 .
  - a polygon in scene has a ratio of 1:1 , but that can be changed inside the UV world .
  
  now if you say you are working with an 3:1 ratio image , \
  im afraid you need to be 3 times more accurate when things move into U than V .
  
  if this IS the problem solved by BodyPaint viewport's feature ( changing the display ratio ) ,
  i believe Houdini can mimic it .
  
  so , just to make sure this is it and since you are reaching 1000 words count ..
  maybe it is worthy to post a picture ?
  
  

I think all you really need to do here is place your non square texture into a square with empty black space…

I am not sure about bodypaint but ZBrush has the ability to recognize UV's that exist outside of the 0-1 square…this is there so that lets say you have two legs that you will be using the same UV space in the end., either overlapping or tiled. Well Zbrush wont allow you to paint on overlapping UV's so this is a work around but really only to get around the fact that you cannot paint on overlapping UV's..

There are some techniques as well were you take a square texture, scale it so that it is squished 2:1 and let the software stretch it back to square. This can help save texture memory for realtime applications with a minimal loss of quality.

Other than that UV's are square, exist 0-1 and I have never seen a program that is different….