[3DS Max] - Straighten UV's Problem

FredCM

Hello!

I'm trying to unwrap the UV's of this pan, and I'm having the following issue with the "Straighten Selection" feature in 3DS Max's UV Editor:



In brief, I'm trying to straighten these UV islands circled in red, but the Straighten Selection tool messes everything up, as can be seen in the far right. I could place some seams in order to isolate the pan holders, but I'm trying to keep everything on the same island. It seems that the Straighten Selection tool only works if the UV island is all quad and uniform, which is not the case. I also tried the "rectify" option in the textools plugin, but it didn't help me at all.

my goal is to make everything as straight as possible but maintaining that rounded shape of the pan holder, looking similar to that "Ideal UV" drawing on the image above. So is there any way of making this in 3DS Max? Any scripts or plugins?

Klunk

you could use the spline functionality for that... drop a circle round the top and pick that you can tweak it with the cross sections

FredCM

@Klunk thanks for replying! I'm not sure if I understood what you meant. Do you know of any tutorials on that? Or, if this is not a problem for you, could you explain this more in-depth?

Klunk

pretty simple.....



select the outer edge as so... (in editable poly) and use Create Shape from Selection.... the in the uv editor select the faces you want to map and select  the wrap::spline option.


in the new dialog you have a pick spline option pick the created spline and set mapping to planar....


and voila

Kanni3d

Straighten only works with perfectly quad loops/strips. Another method would be to detach any other shapes, straighten, then stitch them together afterwards.

FredCM

@Klunk thanks for the detailed explanation! This method indeed unwrapped the UV's, but it ended up being very distorted. And relaxing the island doesn't really help

This is what got following the method you mentioned: 

Klunk

shrink it by 90% in the horizontal

FredCM

@Kanni3d thanks for your reply! Yes, your suggestion works. But the problem is this ends up costing too much time, given that I have to cut off the "problematic" piece, straighten up the quad strip, select each edge that was merged to that piece, apply stitch, and finally, re-align these edges (as shown below).



So, unfortunately, doing that is very time-consuming, even though this is indeed a possible solution. I had already been in a situation where I had to unwrap several meshes with similar issues, and what a headache that was! As you said, Straighten will only work with full quad strips. And I'm aiming for a solution that allows me to straighten even non-quad loops. Maybe there's a script than can do that, but I couldn't find it on my own

Kanni3d

It's a bit time consuming, but that's the nature of (unautomated) UVing in general. If you have those few actions hotkeyed (since this is a common thing to do to get nice uvs) it isn't so bad. Strange that it's deforming it that much after stitching though, perhaps the broken off circular piece needs to have a striaght edge as well before the stitch.

Having perfect UV's is something that will always take manual effort anyway, scripts/plugins only have so much "logic" when it comes to unordinary situations.

Worst case/fastest case, is to just leave out the stitching step. Faster, but you'll just have some extra seams here which may or may not be ideal in your situation, depends on the asset. 

FredCM

@Kanni3d Yes, I guess you're right. Maybe Autodesk comes up with a solution for that at some point.

Following other folk's suggestion, I could solve this problem in RizomUV, which worked quite nicely. The only manual part was selecting the edges I wanted to be straight, apply a Horizontal Constraint to them and then, press unfold and optimize. This could be a little more straight on the sides of the island. I can always manually straighten them up, but I think this is the best I can go with little effort:



Ideally, I should be able to do this in 3DS Max, without having to rely on external tools. But if someone knows a solution for that in 3DS Max, I'm open to hear!

By the way, I have a high-end hotkey pad specially designed for UV editing (haters gonna say this is just a regular keyboard with a bunch of tape on top):

Vexod14

I fully agree with Kanni3d & Klunk, both on methods explained and how these are standards when it comes to manually unwrap your UVs. Like, it's normal to spend more time on things that can't be automated.
The RizomUV result is quite poor for two reasons : 
- center edges are messed up (=will need later select>relax>straighten)
- external app means more clicks. Always a thing you want to reduce and a problem if you need to do that on several models or refine the model's topology for some reasons

On 3dsmax you can also rely on the Peel mode, this one allows you to view unfold in realtime depending on pinned vertices, it starts with two, but you can add more simply by selct+drag them around and see how it behaves best.

Another way to do that would be using the projection method, I did that to project UVs from a flat model onto a more detailed one : 

poopipe

I like that one ^^  - it's something i do often in maya but the projection modifier didnt work properly last time i tried in max (probalby 2015 tbh) 

the question i can't stop myself asking is why you'd do this to a pan other than as an exercise.
Straightening circular things out makes sense when you simply can't fit the object into your UV space, if you're getting artefacts from texture compression (probably not an issue outside of handhelds/ancient hardware) or if you're using trimsheets/tiling maps but it does limit your ability to generate efficient lods and takes an awful lot longer than simply planar mapping the faces. 

Vexod14

I do this for multiple reasons : 
- having cleaner bakes (by reducing aliasing)
- having less space lost in UVs
- easier packing if you need to do manual adjustments
- reusability of your maps
- stacking, trimsheet mapping...etc
- ease VFX through material as it can offer cool flows
- refine a base model that carries the base UVs but lacks some modeling details
- doing that projection after you did the texture can help texture the base model a bit faster/more easily, since you won't mess with mesh bumps & caveats and instead just paint a flat surface
- lightmaps seems less and less used but it can help avoid light/shadow bleed on such bakes if you intend to "generate" auto-lightmaps, which often just use existing UVSet and repack islands into another UVSet

(I also heard it can help getting easier to compress textures, but not sure on that ^^")

poopipe

i get the benefits - i just don't see the tradeoff being profitable for cases like a cooking pot. Usually this is the sort of minor asset that you find in the background and your primary concern is making sure its as fast to make and cheap to render as possible. The difference between chucking a 512 or 256 pixel texture set at it is so small it's not worth worrying about and you're making it impossible to lod the thing quickly to a basic cylinder primitive. 

it's a useful exercise for sure though  and there's been some really good methods demonstrated

gnoop

That uv projection exists in 3d max since v5  and one version it  worked , next didn't  then again  sort of working but with tricks because  half of uv vertexes  fly away  .     I stopped to bother years ago and do it in Blender  where it  works just fine all the time.    Nice to know it seems like working again now .  Why wouldn't they add vertex normals transfer there too and do it real time  like in Blender .

Vexod14

Hmmm for VNormals you have the wonderful NoorsNormalsThief script that still works pretty well, I'm lucky enough to never had encountered a bugged projection UVs, but I admit I use it quite rarely. For the cooking you're right, probably not worth worrying like that, I thought your question was on the grebble part sorry ^^"

Klunk

not thought of that technique for doing mapping..... just happens I have a couple off tools that do just that my own loft and conform mods....

conforming the mapping of  the tube object (channel 1) to that of the lofted line while adjusting the u & v tiling of the loft. There's a wrapping issue where the mapping goes a bit off !