UV maps not in proportion

[Anonymous]

Hi everyone.

I was creating a model of a steel beam and I made the UV maps:

This is the UV map:

You can see that even though the section is quite tall, the UV part is very thin. The top sections of the beam seemed to be the correct sizes, however this part went really thin and I don't know why.

Is there any way to get the part to the correct proportion?

[ekahennequet · Accepted solution]

How did you create your UVs for those elements? Once you've scaled your UV clusters non-uniformly, there is no way to automatically rescale them to match the proportion of your UVs to the object's proportion. I believe there are third-party tools for that, but I'm not familiar with them. The trick is to get the proportion right at the beginning of the Unwrap process.

For flat surfaces like yours, Quick Planar Map tool should give you UVs that are proportionate to your mesh proportion. Note that each time you use Quick Planar Map, it will rescale the UV cluster to fit the 0-1 UV space. Don't worry about that. You can rescale/re-arrange them during the Packing process or just use the Rescale Clusters tool. After you've used Quick Planar Map to each of your UV elements, you can use either Pack UV's if you want Max to automatically rearrange your UV clusters, or just use Rescale Clusters tool if you want to rearrange and re-scale your UV clusters manually. When using Pack UV's, check "Normalize Clusters" and "Rescale Clusters."  Your UV clusters should now be proportionate to each other in scale. If you only want to re-do the "thin" part you mentioned, then use Quick Planar Map for just that portion. Then use Rescale Clusters. You may need to re-arrange your UV layout.

If you don't have a lot of polys, and they're all flat surfaces without curves, then Flatten Mapping and Unfold Mapping tools are quite good at producing UVs with little or no distortions while maintaining proportion. The downside is that they're not efficient at UV arragement. You can certainly use this, then  break/stitch your Flattened UVs or Unfolded UVs.

I would also recommend turning on CheckerPattern to display in the Viewport, so that your can see the distortions (if any).