UV mapping question

[dersutton]

Hello to all.

I'm currently using Maya 2019 and I've run into a challenge that I'm having some trouble resolving.

I have a model that I've UV mapped and now I want to scale the geometry to it's correct size.   I've attached a screenshot to illustrate the UV's. 

The UV's in the red box are too large.

The UV's in the green box are too small. 

The remainder are in the proper scale. 

I would like to select all the UV's and scale them to the proper size of the model.   

In the UV Toolkit, I have tried using the feature "layout" but it only fragments certain pieces of the model.   Is there an option that will auto scale all of the UV's for me?

Thank you.

[Kahylan]

Hi!

When you open the layout options (Shift+LMB on the button), under "Shell Pre-Transformation Settings", change "Shell pre-Scaling" from Off to Preserve 3D Ratio.

This is the automatic option of scaling all the shells to represent their scale in 3D space.
But you can also manually scale UV-Shells by simply activating the normal scale tool and then scaling the UV's.

I hope this helps!

[damaggio]

Yes, that's the layout function that you need, scaling a model has nothing to do with scaling the UV shells, you can use the layout window or you can do it manually with a checker map texture to keep them in the same pixel density.Play with the settings to fit your needs. It will only fragment the shells if those are disconnected "not seamed" or mesh components disconnected.You also don't have your UV custom shelf enabled.Take a look at the docs Derrik.

[dersutton]

Hi

I did check my Pre-transform settings and they were already set to the ones you suggested.     My understanding was that Maya would automatically maintain the scale of the model's geometry.    I just find it odd that Maya seems to pick and choose which geometry it wants to scale up or down while leaving the remainder alone. 

Thanks again for your tip.

[dersutton]

Hello

Thanks for taking time to reply.     
I'll go with the manual scaling as I have all along.   

Thanks again.

[damaggio]

The layout window will make all UV shells even in size as explained below. That's how we maintain correct  texture resolution. Make sure you froze the transformations and deleted history.

[dersutton]

Here is what happens when I freeze transformations & delete history.   One part of the shell fragments but the remaining pieces remain intact and are in proper scale to each other.   This is what's causing the confusion for me.  

What is fragmenting the geometry?

[damaggio]

From your picture you can see that your mesh is not clean, you should examine the mesh closely, use mesh clean up, check your vertices, make sure they are connected and you don't have 2 meshes on top of eachother , enable heads up display.I'm assuming this is your mesh and not something you found on the internet, which should also be checked upon importing.

[dersutton]

I took your suggestions and applied them but the fragmentation continued.   I suspected something more was going on so I downloaded the model from the original site and this time around it worked.  I had to make some slight adjustments manually but I finally was able to get the UV's laid out.   

If I was to guess I suspect the original file was corrupted. 

Just for the record.  I'm using this model to learn Substance painter.  It's key to the tutorials and not much will happen if one can't use the proper tools. 

Again, I really appreciate your time and I believe everything is now finally working as it should.