[SOLVED] Weird UV Unwrapping issue in Blender

[Butler Offcourse]

Hello Everyone,

I have a problem in Blender, I hope you can help me.

Since I can not attach video files here, I am attaching a link for Reddit post (I hope it isn't against the rules) where I asked the same question in a Blender subredit, unfortunately there is no reply. In the link there is the video where I replicated the problem to show:

https://www.reddit.com/r/blenderhelp/comments/ls4lxx/new_materials_messing_my_uv_unwrap_more_in_the/

I have modelled this shoe, then I unwrapped it as seen in the screen. Then I added a material and it works ok. Then I decided to try an other material, modified the Texture Coordinate scales in the nodes and I saw a weird seem forming on the nose part when there was none when I had used the grid for the UV Unwrap. Even tho in the video I didn’t have the uv grid on, but you can see that the pattern of the previous texture is woking nicely. So out of curiosity I checked my UV Unwrap and I saw that it is messed up.

Why is it happening? How can I prevent this from happening?

Yes I can always re unwrap it to fix, but as you may see, i pinned the vertexes, aligned all the side vertexes edge by edge to have a better unwrap, so I'd love it if i can prevent this from happening to avoid having to redo and fix the unwrap after each material change.

Thank you!

Edited February 26, 2021 by Butler Offcourse

[Aquila Kytori]

Yes a UV mapping problem. (Switching UV maps)

Check to see if you have more than one UV map. Object Data Properties Panel > UV Maps.

If so you need to tell Blender which map to use. Instead of starting your material node setup with a Texture Coordinate node use a UV Map node where you can indicate which UV map to use for the material.

 

 

[Butler Offcourse]

Hello @Aquila Kytori , as usual you are very kind and helpful, thank you very much really 😊

I never used the UV Node and after your advice tried doing it. I unlinked the Texture Coordinate and linked the UV Map instead but strangely, even tho from the drop down menu I changed the UV Map, it was always showing the same. And those materials I did not create, those are some pre-made materials coming with the free BlenderKit add on. So even tho I did not manage to fix the problem with the node technique, it pointed me towards the problem tho.

From the right side panel, I went to check the UV Maps of my model, and it had 2 UV Maps normally, one for the single object that I had in the begining, and an other with all included which I used for baking. But both of them are unwrapped in the same way, so it should not cause a problem, but then I realised something. When I am applying the ready-made materials from the Blender-Kit, it is adding a thrid UV Map and it is called “Automap” , I have no idea what is it, how it is created and all, but it was actually the source of the problem. So when I click the camera icon next to the previous maps, it goes back to the old unwrap. I do not know if the material has a node that is forcing the Blender to autounwrap, no idea, but deleting that automap is solving my issue. 

Thank you very much, as usual, you have been very helpful and solved my issue! 😊🙏🏻

[Aquila Kytori]

 

2 hours ago, Butler Offcourse said:

When I am applying the ready-made materials from the Blender-Kit, it is adding a thrid UV Map and it is called “Automap” , I have no idea what is it, how it is created and all, but it was actually the source of the problem.

 

I haven't tried Blenderkit but checked out how it maps the texture to objects:

From the Blender Manuel / Blenderkit page:     https://docs.blender.org/manual/en/dev/addons/3d_view/blenderkit.html

 

" Auto-Map

Add cube mapping UV to the object after drag-and-drop. This allows most materials to be applied instantly to any mesh. BlenderKit generates a new UV map called ‘automap’ and doesn’t replace your previous UV maps. It also resets the texture space of the target object to (1, 1, 1) which enables most procedural materials to have correct scaling. "

 

After adding a material using Blenderkit has the projection method been changed from Flat to Box in the image texture node?

 

What is cube mapping ?

From    https://exposeacademy.com/5-methods-of-uvw-box-mapping-in-blender-2-8x/

"  " Well, basically, it is a method of applying 2D images or also known as textures onto the surfaces of 3D objects by projecting the texture from 6 different directions, top, bottom, front, back, right and left. This mapping method is very useful for quickly texturing box-like objects. ". "

 

The quote from the Blender Manuel suggests it   " doesn’t replace your previous UV maps "

There seems to be an option in the Material menu of Blenderkit to disable the Automap option, have you tried unchecking it ?

 

Above screenshot is from     https://www.youtube.com/watch?v=pSay3yaBWV0    2:27

edit: hmmmmm ..... or perhaps it is just a search option ?? you can let us know.  

Edited February 26, 2021 by Aquila Kytori

[Butler Offcourse]

Well @Aquila Kytori , you are a genius!! it was it, apply automap! I will call you Blender Genius 😅

Having said that, I applied one material with the automap checked to see the image node as you have requested, if it changes, but no, they all remain flat, and anyways earlier there was nothing as I was not using the same material, so it replaces the nodes with the nodes of the new applied material. On the right you can see the automap in the UV Maps menu and on the left bottom corner, you see what a messed up uv unwrap it makes. So first of all I am sharing a screenshot with the automap on where I also show the image nodes:

 

As you see, it immediatly creates a new map called automap and switches to it on it's own.The texture nodes of this shader are all on flat and on the left bottom corner, there is the messed up new UV map. 

Now following your advice, I went to " Import Settings > Automap " and unchecked it. So it is not a search filter but it is a setting on how to import the materials, so, it works like a charm now!  Here's an experiment with a different texture with the Automap unchecked before importing:

 

 

Now that I resolved the issue, I have realised that I have been working on an earlier version of the shoe as the unwrapping is not straight like you showed me two days ago!! LOL 

Thank you very much again Blender Genius! 🙃

Edited February 26, 2021 by Butler Offcourse

[Kyrah Abattoir]

@Butler OffcoursePassing comment on your UV, you are wasting a massive amount of texture space having your object unfolded like this. You should consider introducing seams to break it up further and make better use of that space.

Edited February 27, 2021 by Kyrah Abattoir

[Butler Offcourse]

Hello @Kyrah Abattoir ,

Thank you very much for your reply, it is much appreciated and any advice is always welcome.  

To be honest, on this surface there are already seams, but this was actually the oldest seams that I had put. @Aquila Kytori gave me some advices to unwrap it better and she showed me that I could pin vertexes which I did not know and it is permitting me to do 2-step unwrapping which I did not know I could. 

So yes, the model is not finished yet, neither the unwrapping but since I am impatient,  and curious how it will look, I tend to upload it time to time to sl to see the result and to “amaze” myself as it is the first time in 12 years that I am creating something for SL.  

Having said that, I have two questions

- The reason that I should avoid wasting space is to increase the crispness of the texture, or let’s say to have a “higher resolution” texture in the same space of 1024 pixel bake image, am I correct?

- To save even more space, I could add even more seams, but I do not know (asking your opinion) if it is better to add less seams and waste some space or is it better to add more seams and use the space more efficiently? Because when I am adding more seams, I tend to get more trouble while tileing textures or on procedural materials. 

Thank you!

 

 

[OptimoMaximo]

14 minutes ago, Butler Offcourse said:

Hello @Kyrah Abattoir ,

Thank you very much for your reply, it is much appreciated and any advice is always welcome.  

To be honest, on this surface there are already seams, but this was actually the oldest seams that I had put. @Aquila Kytori gave me some advices to unwrap it better and she showed me that I could pin vertexes which I did not know and it is permitting me to do 2-step unwrapping which I did not know I could. 

So yes, the model is not finished yet, neither the unwrapping but since I am impatient,  and curious how it will look, I tend to upload it time to time to sl to see the result and to “amaze” myself as it is the first time in 12 years that I am creating something for SL.  

Having said that, I have two questions

- The reason that I should avoid wasting space is to increase the crispness of the texture, or let’s say to have a “higher resolution” texture in the same space of 1024 pixel bake image, am I correct?

- To save even more space, I could add even more seams, but I do not know (asking your opinion) if it is better to add less seams and waste some space or is it better to add more seams and use the space more efficiently? Because when I am adding more seams, I tend to get more trouble while tileing textures or on procedural materials. 

Thank you!

 

 

The reason behind a better coverage of the texture space is both your assumption that you're going to get more pixels, therefore a better resolution/crispness, and memory use awareness. Because of the better texture space use, you would get the same visual quality without needing a 1024, say that a 512 would suffice, not sacrificing quality.

Now what you could do to work around the seams issues that you get by splitting the uvs in more pieces is to use a second uv map. I know, that's what you fixed, but you can take advantage of that feature. You can have your current uv map be used for sampling the input material, while another uv map, cut and laid out as needed, would be the target to bake onto. The mapping will take care of texture placement and alignment. When done, trash the input uvmap altogether and the model is fine for upload.

Edited February 27, 2021 by OptimoMaximo

[Butler Offcourse]

Hello @OptimoMaximo , thank you very much for the answer and your advice! 🙂

Ohh now this is becoming interesting. So I will just reformulate your advice to see if i understood it correctly. What you tell me is to make a UV Unwrap just like the one I did for a better allignment during the render. Then you are telling me to make a second UV Unwrap where I add more seams to fill as much as possible the space that I have in the final baking texture and use the first rendering UV Unwrap as an Input and the second UV Unwrap with more seams and cuts as an output and the allignment on my final result will be like the unwrap that I have on my rendering unwrap but it will feel the space like my second unwrap, am I correct?

That is very interesting technique and I never thought about it. There is also the way that @Aquila Kytori has advised me to ,  in 2 step unwrap and already that way the loss of space is much less, If you did not see it, you can see it here:

 

This is her unwrap but already like this you loose much less space compared to mine. 🙂 So that is the goal when I am satisfied with the modelling part of it. 

 

[Kyrah Abattoir]

Yup, you use the full memory that your texture occupies regardless of whether you are using that piece of texture for something or not.

It's not always possible but try to aim for 90% coverage, unless you are using a tiling texture in which case, obviously you want your UV to conform to the tiling instead.

This is one of my most recent uvmap:

[Butler Offcourse]

Hello @Kyrah Abattoir , thank you so much again for your reply! I appreciate the feedback from you guys and I am enjoying using Blender so much, and I still can't belleive how this software can be free, it is fantastic and if, even tho I doubt, someone from Blender Development Member is reading this post, thank you!!  😊 Also thank you to all of who took the time to reply my thread and pointing me out the right way. 🙂

Here's a new unwrap that I did following the guidelines of @Aquila Kytori on my other post, is it better? I could scale in Y the small straight UV's if necessary, but thought that it could cause stretching, need to check them all with UV grid. But here's the result so far, what do you think? 

[Aquila Kytori]

I have to ask ............... why has the shoe's UV's  3 "sole" Islands ?    What is the island at the bottom right hand corner for ?

[Butler Offcourse]

Hello @Aquila Kytori , thank you so much for your reply and I was reading your other reply, try to understand all and reply. 😊

Good question, well, it is useless, it is actually faces that should be deleted lol. As you know, and stated on the other post, I modelled everything separately. The only reason I did this was because I did not know that I could apply different materials to different uv islands on the same model, so I modelled anything that I would use a different material. I also thought that by doing this, I would use less loop cuts to make the transitions between materials sharper..etc. Well, noob mistakes and problems I suppose.

To answer your question, that uv face is something that needs to be deleted, and is useless because I modelled the sole, the heel and the insole separately. So one of those faces that you see are the faces of the sole facing upwards, but completely covered by the insole, so to be deleted and obviously has no reason to be in the uv unwrapping. 😁

But other than that, does it seem like a good space using the one I just showed if we ignore the fact that one of the faces are useless?

Edited February 27, 2021 by Butler Offcourse

[Kyrah Abattoir]

Make a checker material for your object where the check count is equal to your texture resolution if you want to get a feel on the distorsion.

Do keep in mind that transitions between pixels are filtered, unlike what photoshop/gimp shows us. so a stretchy pixel might not necessarily be that visible.

[Butler Offcourse]

Hello @Kyrah Abattoir , thank you very much again for your reply.

Could you please explain a bit more? As a checkered material, I have the default UV grid (set as 1024 pixels) of Blender and I make a new material and use it as a texture. Is that what you mean? or should I do something else?

So you mean, a stretchy pixel in photoshop could result crips in SL?

[Kyrah Abattoir]

No, i mean that if you setup a basic checker pattern in your nodes and set it to be 1024x1024 checks, it essentially gives you a visual aid, of how your pixels are being used.

You can use a larger grid, this is just an example to get an idea at the pixel level.

[Butler Offcourse]

Thank you very much for your reply @Kyrah Abattoir , I will try to figure out how to do it as I am still such a noob with the nodes.  Thank You!

[Aquila Kytori]

@Kyrah Abattoir You mean this ................?

 

Edited February 28, 2021 by Aquila Kytori

[Kyrah Abattoir]

@Aquila KytoriYup, i forgot if it's 512 or 1024 to get one checker per pixel.

[Butler Offcourse]

@Aquila Kytori Than you very much for posting an example of the node! Now I can do it!

@Kyrah Abattoir Thank you very much! I checked a bit of your old topics, there are very interesting ones with many advices!

[Kyrah Abattoir]

@Butler OffcourseI got tired of bumping them

[Butler Offcourse]

@Kyrah Abattoir well I actually find them useful but anyways whoever is curious, would search and find them!  Also your thread about noob people like me starting in Blender was interesting. Gave me some points for me to think about improving myself! ☺️

Ok, for now, I am satisfied with the model and I tried to decrease as much as loop cuts I can and I "achieved" 2.734 Triangles! Well, 1056 of it is only the pipe going around the opening. I could not bring it lower as it becomes a bit too sharp already, but well, still in an "acceptable" way and again I may try to may be add a subdivision modifier in the future and make normals with it to use on this one. I also deleted the body thickness faces (the ones created from the solidify) sitting beneath the pipeing as they are unvisible, so saved some triangles numbers there as well. I could also delet some faces on the toe part but i did not because I want it to look complete if rezzed on the floor.  Now I will unwrap it! 

[Kyrah Abattoir]

@Butler OffcourseDon't think I'm throwing you needless praises, but this looks very good and is a much better high LOD than easily 95% of what passes as "professional" in SL.

I PERSONALLY would join the piping and surface so they are the same piece of geometry rather than "touching" as it will also help you reduce it further when you make (at least) a hand-made medium LOD model.

[Butler Offcourse]

@Kyrah Abattoir , oh wow thank you very much, that is very very kind of you! I appreciate it and it gives me motivation to continue.  How would you join them? With a Boolean Union? I thought that it could mess a bit the topology, but I could try it! Unfortunately for now I do not know other techniques to join them. Well I know Ctrl + J but it does not join the surfaces but it "joins" the models if i am not wrong.

Also I should say that it was rather easy to do with the step by step workflow explanation of @Aquila Kytori 

Could this be considered as an acceptable UV Unwrap? for the heel I do not care a lot, I will be putting a normal leather or a like texture. There is some stretching but it looks acceptable, am I wrong?

Edited March 1, 2021 by Butler Offcourse

[Kyrah Abattoir]

34 minutes ago, Butler Offcourse said:

@Kyrah Abattoir , oh wow thank you very much, that is very very kind of you! I appreciate it and it gives me motivation to continue.  How would you join them? With a Boolean Union? I thought that it could mess a bit the topology, but I could try it! Unfortunately for now I do not know other techniques to join them. Well I know Ctrl + J but it does not join the surfaces but it "joins" the models if i am not wrong.

Also I should say that it was rather easy to do with the step by step workflow explanation of @Aquila Kytori 

I don't know how proficient you are with the knife tool & plain geometry manipulations, If you don't, I would recommend getting at least some basic practice in a separate project for operations like splitting/joining faces, deleting/creating faces, because these will save your life and a ton of frustration when its time to fix something that you accidentally broke.

So this is a very "brief" explanation: you first want both objects you are joining to have the same number of vertices on each side of the cut, you can use the knife too to insert triangles here and there if you don't want to add a complete new row of edges. (Excuse the mockup) When you insert edges with the kinfe too it is important to avoid creationg too many triangles if possible (but they are not forbidden) and stay with quads , that means all vertices will have at least 3 edges at all times.

Next you open both objects where you want to mend them together. By selecting the faces that would be inside the connection and deleting them.

You can then weld the vertices two by two (M key for me but i don't know if that's standard), in the case of this type of piping you'd merge the outer side to the piping to avoid deforming the piping.

Once done you are left with this and the seam should be completely closed, from that point you are done.

But if you want to part it you then can mark the edge as "sharp" (again maybe i'm assuming too much there?)

 

Edited March 1, 2021 by Kyrah Abattoir