How do I convert a curvy UV to a rectangluar UV?

sr3d

How do I convert this curvy UV into a rectangular one without messing up the UV?



I've seen UV's that are rectangular but look perfect.

Is a there a program that will auto convert the left to the right while still making it look good with a texture over it?

musashidan

Headus UV has a rectilinear relax feature for this.
Also, Max has the straighten selection and unfold strip from loop features.
But really, the results will vary greatly depending on how far the edges deviate from the original relaxed shell.
If this is for in-game purposes then it's only really the UV shell border edges that you should concentrate on straightening. If these are straight and the inner edges are closer to the original relaxed shell then you will have less distortion and still maintain a shell more conducive to packing.

AtticusMars

In Blender, straighten out one quad in your UV island then unwrap using Follow Active Quads
This only works on quads, so if your island has triangles in it you'll have to stitch them in manually.

beefaroni

musashidan said:

Headus UV has a rectilinear relax feature for this.
Also, Max has the straighten selection and unfold strip from loop features.

Also, in 3ds max you can use the pelt mapping + pitting (the lighting bolt icon in the UV editor) to put the four corners of the rectangle and then slowly add more pins until its straightened. Works very well for low polys that need to be straightened but don't follow a perfect quad structure or have pieces that come off of them. 

Neox

with that base you can also select a horizontal edge > loop > ring > straighten horizontally, then select an vertical edge > loop > ring > straighten vertically

oglu

i would hit shortcut r in headus... 

musashidan

beefaroni said:

Also, in 3ds max you can use the pelt mapping + pitting (the lighting bolt icon in the UV editor) to put the four corners of the rectangle and then slowly add more pins until its straightened. Works very well for low polys that need to be straightened but don't follow a perfect quad structure or have pieces that come off of them.

Yes, this is the live peel mode. Can be very useful.

sr3d

oglu said:

i would hit shortcut r in headus... 

So in headus I can just hit R and it will do it for me automatically while preserving the quality of the UV?

musashidan

sr3d said:

oglu said:

i would hit shortcut r in headus... 

So in headus I can just hit R and it will do it for me automatically while preserving the quality of the UV?

This is what I mentioned in my first post above: the rectilinear feature.

Here's a copy/paste from my post above explaining why it will/won't work:

The results will vary greatly depending on how far the edges deviate from the original relaxed shell.
If this is for in-game purposes then it's only really the UV shell border edges that you should concentrate on straightening. If these are straight and the inner edges are closer to the original relaxed shell then you will have less distortion and still maintain a shell more conducive to packing.

Mark Dygert

http://docs.autodesk.com/3DSMAX/16/ENU/3ds-Max-Help/index.html?url=files/GUID-A7CC32F5-40BE-4DE5-A364-05E7986D4BA5.htm,topicNumber=d30e265097

Unwrap UVW > Reshape Elements rollout >  Straighten Selection > 

musashidan

Also, importantly, as I mentioned above you should concentrate on only straightening border edges, otherwise your UVs will be distorted.

In Max> run  Straighten Selection> run Relax by edge angles with 'keep boundary points fixed' checked
In Headus> hit R(rectilinear unwrap)> hit F(relax with edge borders unaffected)

Both will give practically identical results.

AtticusMars

sr3d said:

oglu said:

i would hit shortcut r in headus... 

So in headus I can just hit R and it will do it for me automatically while preserving the quality of the UV?

What exactly do you mean by "preserving the quality of the UV"? If you mean maintaining minimal distortion, unless you are unwrapping a very primitive shape (like a linear cylinder with no bends to thickness changes) then you are almost always going to have more distortion with a rectangular UV map. Most decently complex shapes are simply not well suited to a rectangular unwrap. You can reduce the distortion in the body of the island by doing what musashidan told you but you will still have more distortion than if you had used a normal relaxed map.

You need to weigh whether or not the distortion is worth it to have a nice rectangular unwrap. In most cases, if the distortion is not overly extreme then it is not a huge problem for modern workflows that rely heavily on baking and 3D painting. 

sr3d

AtticusMars said:

sr3d said:

oglu said:

i would hit shortcut r in headus... 

So in headus I can just hit R and it will do it for me automatically while preserving the quality of the UV?

What exactly do you mean by "preserving the quality of the UV"? If you mean maintaining minimal distortion, unless you are unwrapping a very primitive shape (like a linear cylinder with no bends to thickness changes) then you are almost always going to have more distortion with a rectangular UV map. Most decently complex shapes are simply not well suited to a rectangular unwrap. You can reduce the distortion in the body of the island by doing what musashidan told you but you will still have more distortion than if you had used a normal relaxed map.

You need to weigh whether or not the distortion is worth it to have a nice rectangular unwrap. In most cases, if the distortion is not overly extreme then it is not a huge problem for modern workflows that rely heavily on baking and 3D painting. 

I see, this was very helpful.  THank you!

bugo

the greatness about Headus is that even if you don't have a topology following, you can still use "R" rect wrap to.

sr3d

Holy crap, the R key in headus UV layout is extremely powerful. It was exactly what I was looking for.

Guys, I made a quick tutorial jpeg image file.

You can rapidly create hair cards with perfect UV's, making sure they are rectangular.

Enjoy!

musashidan

You can save yourself steps 1 & 5 by using the headus bridge script found on scriptspot. No need for import/export

Or stay in Max and: 
run  Straighten Selection> run Relax by edge angles with 'keep boundary points fixed' checked for exactly the same result.

sr3d

musashidan said:

You can save yourself steps 1 & 5 by using the headus bridge script found on scriptspot. No need for import/export

excellent, i appreciate that

musashidan said:

Or stay in Max and: 
run  Straighten Selection> run Relax by edge angles with 'keep boundary points fixed' checked for exactly the same result.

I tried that and the results were not nearly as good. I may have done it wrong. 
Let me try again.
Yea, I'm not sure what I'm doing wrong.  I don't think 3d studio max can handle such a complicated task (lol).

I wonder if maya or blender can do the same thing headus can?

musashidan

@sr3d Just did a quick comparison showing practically identical results. I've done many comparisons between Max & Headus over the years and have realised that Max's unwrap tools are more than up to the task with most unwraps I do(and I've done A LOT!   )

My favourite combo is Max/Headus/Zbrush for all unwrapping. So easy with the Headus bridge/GoZ that it might aswell all be in the same software.