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Tutorial Doctor

UV Unwrapping: Ugh!

25 posts in this topic

Yeah, I know a UV map is flat representation of a 3d model, sort of like a world map is a 3d representation of the world. But who can paint a map of the world using only the geological coordinates of the objects in the world? Sounds like an interesting project, but it is just plain crazy. 

 

The world is not a perfect sphere, but really a messy continuous flow of valleys and hills. So how would I paint a window on the statue of liberty from a 2d representation of the city of New York? Sorta counter-intuitive to say the least. 

 

This stage of the process for making game assets is really getting me, because I don't have a team of people, and I want my textures to be good. 

 

Actually, this would be possible if only the free version of sketchup would let me export my models with the textures correctly displaying in Blender. I can use projection painting for organic models. 

 

So yeah, I am using Sketchup for more hard-surface modeling, and I prefer it too. I looked up a UV plugin for sketchup but couldn't get it to work. 

 

My workflow is Sketchup to Blender to My Game Engine. 

 

But Sketchup to Blender is glitchy (for now) accept if I don't mind my models having that plain white material with ambient occlusion. Blender to My Game Engine is questionable (UV unwrapping is a pain). My Engine doesn't have level design stuff built into it, so everything is imported. 

 

I must find a better solution (don't have the money to spend on Zbrush right now). Any tips, links or tricks for making this UV unwrapping process less frustrating? 

 

 

 

 

 

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Okay, so I did some brainstorming, and figured that the one thing I should get down is UV-unwrapping a curved surface. And the first tutorial I found on doing this is a good start. 

 

http://www.youtube.com/watch?v=8VgLlurusWc

 

Very good tutorial, but all of this for a pipe. 

Edited by Tutorial Doctor
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I'm not sure if I understood your problem. Please be more concise.
 

The world is not a perfect sphere, but really a messy continuous flow of valleys and hills. So how would I paint a window on the statue of liberty from a 2d representation of the city of New York? Sorta counter-intuitive to say the least.

What is generally done is to map different elements with whatever way it makes them look best - so the "world" would be a spherical mapping, the "statue of liberty" would be a cylindrical mapping or a combination of several mappings etc.
In the end, all of these elements are presented in the same flat form (they are all aligned to the screen) when mapped, so regardless of the original mapping projection that you used on each element, they are all aligned and you can neatly fit them onto the UV space.

There's this obscure modeller, DeleD, specifically made for level design. It used to be a commercial product but was later released as open-source and the community worked on it, releasing it under a "CE" community-edition. Perhaps give it a try?
http://www.delgine.com/index.php?filename=product_deled Edited by Kryzon
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Okay, so I did some brainstorming, and figured that the one thing I should get down is UV-unwrapping a curved surface.

Another option is to unwrap that surface before curving it: it would be a simple, straight cylinder.
When you curve it with a "bend" modifier, it should preserve that mapping.
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There's this obscure modeller, DeleD, specifically made for level design. It used to be a commercial product but was later released as open-source and the community worked on it, releasing it under a "CE" community-edition. Perhaps give it a try?

 

Thank you for that tip! I am downloading it right now. I have been looking over a few tutorials from Andrew Price also, and I think I have found a way to do this faster by using  the "Project from View" uv unwrapping, and then just editing the UVs. 

 

DeleD reminds me of 3ds max a little. I think this is going to be a good software, and it isn't so clunky either. Thanks again. 

Edited by Tutorial Doctor
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Hi,

 

smile.png

 

Hey, we are really talking about an area here that is really an art!  Great art typically is not easy for the artist!

 

My absolute favorite program for UV mapping and applying normal mapping of textures is Wings3D.  It imports and exports in a bunch of standard file formats. 

 

Blender is next on the list for these two areas of modeling.  If you want good unwrapping, then it just takes a lot of practice. 

 

Skill and hard work are far more important than the software used. Part of the skill is to learn to focus on one area of the model and texture at a time. For example, if you draw or otherwise make a temporary outline of lips or eyes as a layer in a 2D program such as GIMP, then you should see that outline of the character part in the UV map viewer of the program that you are using.  Next you align all the completed part outlines (sometimes called a void) with the 3D surfaces by moving those surfaces in the UV map viewer.  Later you can hide the outline layer in GIMP (or other 2D image manipulation software) or even make it barely visible as a guide to add your own face or other body parts.

 

There are plug-ins for different software, for example, baking textures and painting, and some come with such features.  More research is needed by you to find the right combinations of available features for this particular workflow pipeline. 

 

Look more closely at Blender.  Take a look at Milkshape3D http://en.wikipedia.org/wiki/MilkShape_3D  A friend of mine who is also a pro 3D modeler uses Milkshape3D for much of his work. It has a huge export file format list.  I can't remember if you can bake textures, but take a look.

 

Extreme high quality, even "photorealistic" characters can be made using these manual techniques.   They are difficult because this is an art form.  The advantages are extreme photorealistic quality with the potential of no money cost to the artist.   

 

When it comes to custom art (made by you) it simply takes research and very skilled artwork.

 

I hope that I helped you with information leading to the right exchange of model file formats so you can get all that you want in this.

 

 

 

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Any tips, links or tricks for making this UV unwrapping process less frustrating?

Here are some tips:

1. Unwarp only meaningful regions of the mesh and never the whole mesh at once. If the tools supports it (blender does), then mark the edges as uv-edge to create islands of surface regions.

2. Consider, that there are two distinct approaches to texture a model. The pre-defined texture unwrapping and the custom texture approach. If you use pre-defined textures, eg you have an existing stone-wall texture, you unwrap a region and use the uv-editor to drag the 2d grid over the exsting texture until it fits. The other way is, to unwrap a mesh, use a test texture (eg checked ) and try to utlize the target texture best you can. In this case you use the uv-editor to position, rotate and scale regions of the mesh onto a (single) texture until you have almost no space left over, a good, harmonic resolution etc.

 

The pre-texture approach is often used for (modular) environment art, whereas the custom texture approach is for single properties, characters and items.

 

Unwrapping and texture painting is like rigging and animation. Unwraping (rigging) can be done quickly, whereas painting (animation) is the more time demanding part. But if you are not careful with the unwrapping(rigging), then you will have a lot of trouble avoiding artifacts while painting(animating), like seams, stretches, different texel resolutions etc.

Edited by Ashaman73
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The other way is, to unwrap a mesh, use a test texture (eg checked ) and try to utlize the target texture best you can. In this case you use the uv-editor to position, rotate and scale regions of the mesh onto a (single) texture until you have almost no space left over, a good, harmonic resolution etc.

 

I so forgot about that method. I actually did this once for a face, but I got bad artifacts at the seems. And I know sometimes people have to hide seems (behind an ear or something, or under a hair object), but I have no idea how to mark the seems well enough to hide em. haha. 

 

Right now I am trying to unwrap a sky dome into a rectanglar shaped UV so I can just add 2d images of skies to the dome. Trying to do it on my own to learn more about UV unwrapping in Blender. I am wondering if there is any type of best practice, or any rule-of-thumb for this, or if it is just so various that no one figured it was worth the time to create a standard workflow. 

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Okay, I did it! Sorta. I took some advice from the feedback here and I unwrapped each section with the best method for getting it close to what I wanted.

 

I unwrapped the top with just a regular unwrap, and I unwrapped the rest of the faces with a spherical projection ONLY AFTER I HAD MOVED THE CAMERA TO AN ORTHOGRAPHIC SIDE VIEW (which is important to getting it right). 

 

Edit: Well, I still have a really ugly seam right along the edge, and since I unwrapped the top the way I did, when I try to weld it, things get ugly. Now I have to figure out how to unwrap a circle into a flat plane. hehe. 

 

Screenshot%20%28953%29.png

Edited by Tutorial Doctor
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Tried something different here:

No seams. I did a "project from view" unwrap from a top orthographic view. 

 

Screenshot%20%28954%29.png

Edited by Tutorial Doctor
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Okay, so I guess the word is a "mercator projection" and this link is perfect! I was actually trying to put a loop closer to the pole just to minimize the artifacts at the top, but I couldn't get it to work. I will update with a picture:

 

http://blender.stackexchange.com/questions/3315/how-to-get-perfect-uv-sphere-mercator-projection

 

Edit: I am getting a flat unwrap, but I am still getting a seam, but that is mainly because the images I am using are not seamless. So I guess this helps with the dome at least, perhaps this "follow active quads" feature of Blender will help a little. 

 

By the way, I started with a full sphere, and after I followed the steps in the link above, I deleted the bottom half of the sphere. 

 

Screenshot%20%28955%29.png

Edited by Tutorial Doctor
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UV unwrapping is, indeed, a tedious task. I don't really have anything to add to the discussion to make it easier, since I struggle with it myself even after all these years.
 
However, I would like to just throw a suggestion out there. How about eliminating UV unwrapping entirely? Depending on the style you are shooting for, it is entirely possible that you can make do with entirely procedural coloration/texturing, rather than texture mapping. Look at games like Cube World, which has minimal (if any) texturing, and relies almost entirely on coloration and AO to provide the rich visual appearance. On the other end of things, if you want more visual detail than simple vertex coloration, you can use techniques such as tri-planar texturing for terrain and landscape objects, and with some creativity, it can be used for all sorts of things.

Granted, doing procedural coloration and texturing moves work required from UV unwrapping over to additional shader creation, but for a programmer it can be a worthy trade.
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Thanks JT! I am all for avoiding UV unwrapping. I will check out Cube World indeed. And I will look into tri-planar texturing. I sort-of got something workable from the method I mentioned above. Here is a screenshot of the level:

 

Edit: That Cube World game gives me a good idea!

 

Screenshot%20%28956%29.png

Edited by Tutorial Doctor
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Avoiding seems with UV mapping often takes skill in 2D image manipulation software.  Using the same texture element on both sides of the UV seem allows the artist to align the surface parts in the UV map viewer.  Usually it is possible to make the seem invisible.

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UV unwrapping is, indeed, a tedious task. I don't really have anything to add to the discussion to make it easier, since I struggle with it myself even after all these years.
 
However, I would like to just throw a suggestion out there. How about eliminating UV unwrapping entirely? Depending on the style you are shooting for, it is entirely possible that you can make do with entirely procedural coloration/texturing, rather than texture mapping. Look at games like Cube World, which has minimal (if any) texturing, and relies almost entirely on coloration and AO to provide the rich visual appearance. On the other end of things, if you want more visual detail than simple vertex coloration, you can use techniques such as tri-planar texturing for terrain and landscape objects, and with some creativity, it can be used for all sorts of things.

Granted, doing procedural coloration and texturing moves work required from UV unwrapping over to additional shader creation, but for a programmer it can be a worthy trade.

 

Procedural baking of textures has much room for improvement, so expect progress there in coming years.  Eventually software will easily take point data and associate it with locations on the texture to automatically align 3D surfaces with those points, thus eliminating the seems. The 3D theory is in discussion about micro pixels and also connecting 3D coordinates more closely with 2D texture coordinates. However, with current computer rasterizing, this is complicated and unreliable at present.  Even with progress down the road, I expect that some manual unwrapping and making the associates between 2D and 3D in the UV map viewer to be needed for a long time to come.   

 

Of course, nothing now beats taking a high density image and applying it to surfaces for an exact representation of what was photographed.  Complicated surfaces will in this case still need UV map work, so tedious UV map work for complex surfaces is here to stay for a while, isn't it?

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After watching the above series, I feel MUCH more confident tackling UV unwrapping. The one thing he said that helped me understand how to mark seams was that it is just like using scissors to cut through a piece of fabric. 

 

So I imagine the object as a piece of fabric that comes loose where I cut it. I imagine all continuous faces as a continuous piece of fabric.

 

I was able to unwrap a cube with ease!

 

As a note, I used "Follow Active Quads" as the unwrapping procedure. 

 

Screenshot%20%28961%29.png

 

 

Screenshot%20%28963%29.png

 

 

With just one small cut from the north pole to the equator of one loop of the sphere, and selecting the face adjacent to the two meridians, and then selecting all, and choosing "Follow active quads" I was able to get a good uv unwrap on this sphere:

Screenshot%20%28966%29.png

This still has bad seams, but I will get it eventually. Anyhow. Good thread!

Edited by Tutorial Doctor
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Just so you know the potential, I have on rare occasion cut and unwrapped objects with very many polygons and dozens of cuts.  A model of a particular ship hull that I created a couple years ago (approved for use in a game) took a whole day to UV map, but when I was done it had no seems and no distortion in the texture mapping.  Another model had about 120,000 polygons, hundreds of individual objects, and several textures to be mapped, which took about two weeks to UV map. People say it looks awesome like its real. It is in a simulator.

 

So, since all 3D modelers start like you,  then appreciate the huge potential you have in this art form. smile.png

 

Keep having fun and work hard at it!  biggrin.png

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Thank you 3Ddreamer.

I have thought of a new process that mimics real life. I should mainly focus on a material that tiles seamlessly, as objects in real life are wrapped in material this way. And I mainly need to work on hiding seams rather then trying to get rid of them.

So, have you ever dreamed in 2D? I know it sounds weird, but I seriously had a dream that was in the style of paper cutouts. Haha.
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So, have you ever dreamed in 2D? I know it sounds weird, but I seriously had a dream that was in the style of paper cutouts. Haha.

 

Yeah, once in a while after spending a lot of time with the 2D aspects, that night I might have a dream or two about all this.  rolleyes.gif

 

tongue.png

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Just wanted to update my findings. I finally have a very simple way to get my sketchup buildings into Blender and textured. All I had to do is take of the ceiling and the floor, and make one single seam along one corner of the mesh. I just have to upload the ceiling and floor separately. The texture comes out seamless enough and since it is rectangular, I can just load in any 2d image. 

 

Screenshot%20%28969%29.png

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Get used to finding ways to hide seams, so that almost no matter what software and plug-ins you use, your artwork will look nice. Sometimes no manual unwrapping is necessary such as with painting, bump, procedural shaders, and so forth. These will take pressure off you in the UV mapping as well as expand your capabilities which can only help the attractiveness of your art. 

 

After months, a year or two, then you will have the skillset to make nice art that both you and your gamers will enjoy.

Edited by 3Ddreamer
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Good point. I should figure out this uv we wrapping thing. I just wanted to get the game going, because this was a big blockage to the workflow.

I'm working on the programming and art side at the same time, as well as the design side. My next venture is character animation (3d). Thanks again
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I know you want to just get past this and move on quickly. UV mapping is one of the most annoying processes you can do as an artist ( next to skin weighting, fuck that shit ) so I get it... but you really do need to spend time learning it. The difference between a perfectly placed seam and a randomly placed is HUGE! Especially if you are putting your art for other people to texture you. So, take it from those of us who have spent the time to learn this art.... its worth knowing.

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