What is the deal with game character wrinkles?

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LoriGriffiths
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What is the deal with game character wrinkles?

Post by LoriGriffiths » Sat Aug 08, 2015 3:38 pm

I got a comment over on my website about wrinkles/folds in clothing for game characters. This isn't the first question I've gotten on this. Here's the post.
HELLO Mam thanks for extremely helpful tutorials but for a game art student these clothes are useless until we got wrinkles no matter real or artificial as you can see in the link http://devblog.sherlockholmes-thegame.com/page/3 please check the link and read it and please help us to achieve folds like that. i searched a lot but find nothing who is teaching these techniques for realistic folds how to customize fabrics specially weft and warp properties,every one is making good clothes but helping to achieve folds and not even touch fabric physical properties please help in that topic.
The blog posts are really interesting and they are doing good work. The posts are older and you can see that MD is used, although not mentioned specifically. Here's my quandary. What's the deal with game character modelers and wrinkles?

I posted back to this comment and said that MD doesn't do these wrinkles because it's attempts to drape realistically. I don't know how many times I see a game character standing stock still with what appears to be well fitted garments and they are covered in wrinkles and folds. Why do they do this? I could understand if the garments were too large or small, certainly ill fit causes pulling or sagging.

Also, during animation, garments will contort somewhat. So I can understand why a few 'fake' wrinkles might help for realism while walking or fighting.

Any game folks out there? Why does the industry do this?

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wetcircuit
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Re: What is the deal with game character wrinkles?

Post by wetcircuit » Sat Aug 08, 2015 10:52 pm

LOL well the answer is pretty obvious – it's suppose to look "cool"....

This originally started as busy surface detail in specialFX movies (think StarWars-era spaceship hulls) called "greebles" (or "nurnies") - cosmetic pipes, hatches, crevasses, joints, ledges, jutting windows and docking bays etc etc that are suppose to give a sense of scale to an otherwise large formless surface. For examples: the Death Star and the Borg Cube are two simplistic geometric shapes which, without all the tiny surface details, would look ridiculously unintimidating. Needless to say there wasn't a whole lot of functional purpose to these details, often added by secondary artists.

In the game world, there is an advantage to having a low-poly mesh enhanced with high-detailed normal and ambient occlusion maps to create the same impression of surface scale – and there are memory advantages to dynamically changing the maps at a given distance to the camera, as more detail is necessary in close ups and less detail when far away. It's now such a hardcore cliche that so-called AAA games all employ highly detailed image maps like this, models covered in bogus details which are non-functional. Space stations are covered in "grunge" and worn metal surfaces (where dirt and weathering would never exist), and clothes are covered in wrinkles as if everyone is wearing vacuum-shrunk parachute pants from the '80s.... I once saw an exhibit of 16th Century Italian art student sketches where the effect of da Vinci's exquisite musculature was badly copied by lesser artists that had no real concept of anatomy – the result was weird, lumpy bodies that looked like taxidermy disasters.

The typical workflow for game clothes would be to model a low-detail outfit in MD, export to 3DCoat or zBrush, retopo the mesh, and paint details onto high-res maps (or bake the maps off a high-res mesh). My experiments in MD have involved exporting a "low res" mesh with a particle setting of ~24, and a "high res" mesh of the same project with a particle setting of ~6 where I have cranked up the warp and weft to create deliberate wrinkles in the clothes.... I use 3DCoat to bake normal and occlusion maps off the highres version, and transfer them to the low-res mesh which has the exact same UV map from MD.

Previously I had suggested that a game engine forum be created here since there are a lot of issues specific to game engines (although not specific to any particular engine), but that suggestion was shot down by the editor here. This "wrinkle" workflow would have been one of those topics.

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LoriGriffiths
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Re: What is the deal with game character wrinkles?

Post by LoriGriffiths » Sat Aug 08, 2015 11:30 pm

WetCircuit,

Great explanation. That makes perfect sense. Those wrinkles just creeped their way into being and now it's the norm. I still think it looks silly, but I'm a garment realist. I want people to think that my garments are photos of the real thing. I don't think I'd do well in the game side of things.

I am the admin and due to my lack of knowledge about game development, I didn't understand how a game category in this forum was relevant. You've certainly proven your point with this post. I'll create a category for you and put a copy of your post in it for others.

Thanks so much.

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Re: What is the deal with game character wrinkles?

Post by ClusterOne » Wed Aug 12, 2015 12:57 pm

wetcircuit wrote:LOL well the answer is pretty obvious – it's suppose to look "cool"....

I partially agree with you here but the problem is both technical and artistic in my opinion. As you mentioned, developers often go overboard in pursuit of detail. That being said unlike a static mesh examples you mentioned, you have to take into account deformation when you simulate clothing. The problem with applications like MD is, while the simulation is physically based, the deep convoluted folds tend to animate poorly when baked down. Developers want clothing that animates well and thus often go with simple, shallow, overdone generic folds that look acceptable in most animations (versus a physically based simulation that looks great in a T/A pose but breaks completely when animated).

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Re: What is the deal with game character wrinkles?

Post by MorgaineChristensen » Wed Aug 12, 2015 9:59 pm

I don't know about other gaming engines but having been a long time member of Second Life, mesh, with or without folds, is only a recent option. But, if I am reading what the poster wrote correctly, prior to mesh, clothing depended on In-World created prims (flexible prims for skirts, sleeves, hair, etc) or sculpted pieces (sleeves, collars, wristbands, etc.) or system layer clothing. Originally, the clothing was flat 2D textures applied to the In-World clothing system. SL had a UV Map template for the mesh avatar, which could and still can be imported into Photoshop/Gimp and clothing textures created. As such and over time, those with creative skills and the clamor from Residents for more realistic looking clothing, saw the advent of shadowing, wrinkling, and shading of the flat 2D clothing textures using graphics software. Partially, there was no In-World shadowing at the time so imaginary folds and wrinkles were created along with shading for added depth and realism to once flat and blah clothing. It is an art form unto itself and has progressed over time.

My guess would be, from the pictures in the link, this is something similar. A graphic enhancement to the mesh to provide added details, which AO, shadow, and other mapping may not be detailed enough or subtle enough for. Or, if some of the mesh is not draped say in MD but flat, like a shirt under a jacket, handcrafted wrinkles or shadows can take a flat mesh shirt and make it into something much much more realistic. Also, if you are worried about the global cost of polys, and lord knows MD items can be pretty high in polys...even after retopolgizing elsewhere...the savings using graphic illusions can be quite useful. Plus, you have to remember, in a gaming environment, your camera will not be zoomed in on the detailing usually. The graphic artists are going for illusion of shadows and folds to add to the over all experience.

Here are a couple of examples that might be useful to those asking you those questions.

https://www.youtube.com/watch?v=YSZt0yObxKw
https://www.youtube.com/watch?v=ihLtxqQ9zWs

SavageCreature
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Re: What is the deal with game character wrinkles?

Post by SavageCreature » Sun Dec 20, 2015 6:53 pm

I don't really know if any additional information is important or desired on this topic, but I ran across this thread as I was trying to control wrinkles in MD and thought I'd throw in my two cents.

All the points that have been made so far are at least in some way partially correct and perfect valid answers. In video games there are definitely constraints that don't exist in other media. However, in my experience it's a lot more a matter of, stuff is really wrinkly.

MD may simulate realistic wrinkles for a garment that has been worn once, but it really under-does the job for nearly any other situation. Unfortunately I can't share the scans we use at work, but there are plenty of examples of full body 3D scans of real world clothed people that demonstrate an incredible amount of fabric deformation.

Image

I could provide a large number more examples, but I think this one is sufficient. This is a 3D scan of real world objects, not an artist's interpretation. These are the sorts of wrinkles that those of us who create characters for the entertainment industry are trying to reproduce. It's quite a bit more difficult than it might seem, and as we're almost always under pressure to produce more, faster, we're always looking for a better way to do it than taking the time to sculpt them by hand, which takes forever and is hard to make convincing. The current methods of simulation we have available to us still require a lot of augmentation to after the fact to get the desired look.

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LoriGriffiths
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Re: What is the deal with game character wrinkles?

Post by LoriGriffiths » Mon Dec 21, 2015 6:44 pm

SavageCreature, thanks so much for providing these real scans. I would agree, you have lots of fabric deformation.

What I was talking about was wrinkles sculpted where they make no sense. These images are perfect for illustrating my point. From left to right:
1) His shirt is deformed because of his arms being crossed and his pants because they are oversized and the knee armor is bunching it.
2) The fabric is lightweight and the sleeves are long, causing them to scrunch. The pants are actually wrinkled fabric, which would be pretty easy to do as a bump.
3) The sleeves are pulled up to the elbows and it distorts the shirt, the pants are oversized and long, secured at the ankles, which creates all the wrinkles, particularly at the knees.
4) The pants again are large and the fabric is wrinkled itself. The t-shirt is pulled into the armpits because it doesn't fit him well. Likely his arms are larger than the shirt can accommodate.

All of these can be accomplished in MD using the right patterns and fabric settings. You also need to get the model/avatar out of the A pose and into something more realistic. The trick is understanding garment and fabric properties well enough to make these 'real' deformations happen. If this type of thing does plague many CG artists, would a video explaining how to do this in MD be helpful? I'd be willing to do it.

I really appreciate your time in preparing such a comprehensive post.

Lori

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Re: What is the deal with game character wrinkles?

Post by Rosemaryr » Tue Dec 22, 2015 5:00 am

Another quality of MD fabric that should be examined in more detail, is the friction property.... how much 'cling' is causing a fabric to stick to the avatar's skin will cause wrinkling. Especially with lighter fabrics and the smaller, finer wrinkles.

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Re: What is the deal with game character wrinkles?

Post by SavageCreature » Tue Dec 22, 2015 5:45 pm

You make good points, once again.

However, I have two things to add.
In games we don't have blend shapes or fabric simulation. At least not the sort of simulation that MD provides, for sure. The wrinkles the clothes have in A pose is all the wrinkles they're ever going to have. Consequently wrinkles have to be included that will look at least plausible for all body positions. When the character in the game bends their arm at the elbow the amount simulated fabric deformation in-game is pretty much absolutely none. So, when the character is in A pose, we sculpt wrinkles around the elbows so when they're bent they'll look more correct. After all, how often do you see a character standing around in an A pose in a video game?

Secondly, and this is part I have no idea how to accomplish in MD, fabric creases. There's a reason we need to iron our clothes. When we bend and fold and all the other stuff we do to our clothes while we're wearing them, the fabric creases and the folds and wrinkles stay in the surface of the fabric. There's a great deal of that going on it pretty much all of the scans shown, especially in his cargo shorts

I don't want you to misunderstand me. MD is a fantastic tool and has made clothing CG characters a quantum leap easier than it used to be. I in no way intend to imply I feel otherwise. I'm just saying that at my skill level with the software (decidedly not an expert) it's still not quite providing the results most artists are looking for so additional sculpting work is added after the fact.

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LoriGriffiths
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Re: What is the deal with game character wrinkles?

Post by LoriGriffiths » Tue Dec 22, 2015 7:15 pm

Trust me, I'm not defending MD. I am actually not a big fan of the company at all.

I do see the problem. You need your character in A pose, but you need cloth deformation that will hold up regardless of what the character might be doing in a game. That is a unique problem. You might try using pins in MD to hold the fabric to create more wrinkles, rather than having to sculpt after export.

The creases you describe in the second paragraph sound like you are talking about fabric wrinkling. Like if you wadded up some clothes and left them on the floor, they'd be all wrinkled. Not a process of wearing the garment at all. Have you tried bump/normal maps for this? I think it might work, although I've never given it a go. The wrinkles would be subtle and trying to sculpt them would be very, very hard. That's why I think deformation with a material/texture might be more suitable. I'll have to give that a try sometime and see what I can do.

Hopefully, this is a short term problem for game developers. I can't wait until you have cloth sim in your games and it really comes to life. It's coming, I just don't know what the time frame is.

Thanks for posting. It's been very educational for me. I think lots of my audience on YouTube are game developers. I really like to learn about what they face and try to find solutions.

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