Question about uv in Maya

triton

Hi,

This is my first model in Maya and I am doing my UV for the first time,

Do you guys conveting your mesh to smooth with "Smooth Mesh Preview to Polygon" and then you do the UV?

Because I am doing the UV with a mesh and when I press 3 on the keyboard I see the mesh becomes red in the UV.

prixster

when I press 3 on the keyboard I see the mesh becomes red in the UV.

So does it happen only with Smooth Mesh Preview? Can you check whether the same is happening when you smooth / subdivide the mesh?
Personally I would do the UVs in the initial blocking stage. Then as i subdivide it, i keep checking the UV distortion.

prixster

The left image is Smooth Mesh Preview in UV shaded view. In my case there's no red in the UV. And if you are talking about UV Distortion view (white shading preview) then yes, smooth mesh preview shows a little bit of distortion but that can be fixed by smoothing the mesh by a level. I would not advice you to do UV in 3 mode.

triton

prixster said:

The left image is Smooth Mesh Preview in UV shaded view. In my case there's no red in the UV. And if you are talking about UV Distortion view (white shading preview) then yes, smooth mesh preview shows a little bit of distortion but that can be fixed by smoothing the mesh by a level. I would not advice you to do UV in 3 mode.

Thank you for reply.
Yes I see the red distortion in the UV only when I press 3.
So do you recommend that I convert the preview to an actual smooth mesh and then do the UV? because I will send the mesh to Substance afterwords.

throttlekitty

Can you show a picture of your model and uvs?

triton

Here is the mesh without smooth preview:

And here with smooth preview:

Thank you

alibaba17

turn off the icon will do~

throttlekitty

Your UVs are nice and clean, nothing to worry about there. IIRC that shader sometimes has issues with scale. I personally don't use this function much, but it can be nice. I remember it constantly showing me problems where there really weren't, I find the test checkers more helpful.

triton

Thank you so much guys

triton

Hi,

There is something very confusing to me.

How come the UVs are the same on both meshes but one of them its texture is reversed? how come?

One of them is duplicated and reversed with Scale -x but the UVs are not showing in red to indicate it's flipped!

Alex_J

You have flipped the mesh, but the UV coordinates are not flipped in relation to that mesh. If you select the UV shells in the UV editor, and flip across U or V (i think that is in the transform palette of the UV toolkit), then they will be red to indicate that they have been flipped. 

alibaba17

scale -x equal to mesh flipped normal and uv will become red  when you freeze transform

triton

Thank you.
So if I flip the coordinates in the UV editor and it becomes red that is ok? and that is not going to be a problem with other texture programs like Mari or Substance?

Sorry to ask such a basic questions because this is my first time I am doing a serious 3d project.

Alex_J

The UV coordinates are a map. The 0-1 space represents where the texture is going to be, and the UV's are saying where the unwrapped mesh is going to sit on that map. So if you flip the UV shell, you are just reversing the direction the texture is going to appear on that shhell.

It's way harder to explain and understand than it is to see. Once you see it for yourself,  it's quite simple and intuitive. Export your mesh as is, one with the shell not flipped and another with the shell flipped, make some simple texture, and watch how it gets applied. On one of the meshes, that flipped shell will be getting the same thing, but reversed.

You could do the same thing in your 3d app. Get ahold of some texture -- anything will do but something like a grainy wood texture might help visualize easier. Duplicate your mesh, flip some or all shells on one mesh and leave the other alone, and apply that texture to the diffuse channel on both.

triton

BIGTIMEMASTER said:

The UV coordinates are a map. The 0-1 space represents where the texture is going to be, and the UV's are saying where the unwrapped mesh is going to sit on that map. So if you flip the UV shell, you are just reversing the direction the texture is going to appear on that shhell.

It's way harder to explain and understand than it is to see. Once you see it for yourself,  it's quite simple and intuitive. Export your mesh as is, one with the shell not flipped and another with the shell flipped, make some simple texture, and watch how it gets applied. On one of the meshes, that flipped shell will be getting the same thing, but reversed.

You could do the same thing in your 3d app. Get ahold of some texture -- anything will do but something like a grainy wood texture might help visualize easier. Duplicate your mesh, flip some or all shells on one mesh and leave the other alone, and apply that texture to the diffuse channel on both.

Thank you so much for the explanation.

Alex_J

No problem. I struggled with understanding this stuff for awhile, though I had plenty of good instruction. It wasn't until I just went forward and went through each step to make a game asset a few times that things started clicking, and I realized that none of it is as complicated as it seems at first.