[SOLVED]Setting UV for 1 meter per tile (regardless of texel density)?

bentraje

Hi, 

Is it possible to set 1 UV tile for 1 meter measurement in real world?
All the references point out to texel density but I am not after the texel density but rather the real world measurement of 1 meter having a 1 UV tile. 

Is there a way around this?

Thank you for looking at the problem.

poopipe

That's  what setting texel density is. 

bentraje

Correct me if I'm wrong. The texel density needs a map size. 1024 or 512.  I want to be indifferent of the map size. Hence the, 1 meter to 1 UV tile for the mean time. 

musashidan

1m to 1UV tile has no meaning without a texel density. A UV tile is infinitely large or small without a map size variable, so how can something that doesn't exist in the real world have a real world size? What you're proposing doesn't make any sense. You can do what you like, but ultimately it will be tied to a map size.

poopipe

1m to 1UV tile has meaning in relation to a frame of refetence.  Texel density comes from how many pixels are in the texture you put in that space.

In the case of conventional UV layouts the frame of reference is the scale of the object.  If you scale the object, texel density in relation to other objects changes. 

If you want to have a fixed density regardless of the scale of an object you need to map in world space - which is something you need to do in a  shader

musashidan

Yes, but I mean in relation to the texture. For example, a tiling brick wall being the classic. Or in the case of a unique 0-1 asset, the details in the texture in relation to the scale of the mesh.

poopipe

I don't think I explained myself very well..

... mapping to a texel density is the same as mapping to a distance, you're just defining the distance in pixels rather than metres. 

The important number when clicking the set texel density button is the ratio between texel density and texture size, not the values themselves .
Texture size/texel density = metres per uv tile

  
In the OPs case the ratio is 1 so the numbers for density and texture size simply need to match. 


(assuming the density is per m of course, you'll need to account for cm etc...) 

bentraje

Thanks for the explanation, but I'm not quite sure the question has been answered:
"Is it possible to set 1 UV tile for 1 meter measurement in real world?" 

A brute force of doing so is like creating 10cm plane. 
By default, it fills out the whole UV tile. Since I'm aiming 1 meter per 1 UV tile. I'd have to resize (downwards) the UV of 10cm plane as much as 90% for it to be in a real world 1 meter per 1 UV tile. 

Thank you for looking at the problem.

Alex_J

What are you trying to do, specifically?

"Texture size/texel density = metres per uv tile"

i believe the answer is right there. ^

So if you make your terrain out of 1m cubes, you can apply one texture sheet to each. Dunno why you'd need to do things that way -- seems like there is some kind of misunderstanding.

bentraje

Thanks for the response @BIGTIMEMASTER

Regarding ("Texture size/texel density = metres per uv tile"), 
I'm not sure how to make my 1 meter objects per 1 UV tile with the equation above because I don't have a texture size/texel density in mind  

For the sake of the argument, even if it is 512, 1024 or 2048. I want it all those map size to equal 1 meter per UV. 

bentraje

RE: trying to do specifically. 

I was tasked by a visualization firm to UV objects 1 meter per UV tile. The materials are probably procedurally generated. That is why there is no specific map size in mind. 

poopipe

As I said above you simply need to set density based on a 1m texture. 

You don't need to know a density or size. The numbers you give the tool are irrelevant as long as the ratio between the two is 1:1. 
In maya you could set texel density to 512 px/m and tell it the map size is 512 before clicking the button.

If you're using planar mapping or similar, simply set the dimensions of the map gizmo to 1 metre

bentraje

@poopipe

Thanks for this: 
"In maya you could set texel density to 512 px/m and tell it the map size is 512 before clicking the button." 

That made it clear  

Have a great day ahead!