In Art Spotlight, we invite Sketchfab artists to talk about one of their designs.
My name is Justin Thornhill Phillips, I’m an American artist/animator for a small games company. I studied design and animation at the College of Design at NC State University. Here’s my website and my twitter. I like whimsy and fantasy and anime and I like action-y video games like Smash Bros and Dark Souls and Assassin’s Creed. But you aren’t here for my life story, so let’s get on with talking about these characters. If you want to check the game out you can get it for free on the app store!
Motivations & Platform
These models were made for a game, and a big reason why these characters are the way they are is because our platform for this game is mobile devices. We wanted to create simple forms with crisp colors and we wanted to do it cheap.
The characters themselves don’t even really animate their arms and legs in the game, they all just sort of hop around based on one simple box animation we made with a subdivided cube. All the characters are just bound to that skeleton and we use Autodesk Maya’s ‘copy skin weights’ function to transfer the simple skin weights from the cube onto the more complex geometry.
The pipeline for our characters was pretty straightforward, concept to ZBrush to Maya to Unity. It may be a bit uncommon for simpler characters to be modeled this way, but it affords us a way to quickly block out the form before committing to the tedious process that can be traditional box modelling. Retopology also allows us to define exactly where UV edges will be more easily.
For these models, we just needed base models to use for retopology, so making a single smooth mesh was unnecessary.
For more complex models, we made more complex base sculpts, but the concept is the same; simple overlapping blob meshes that define the form. When we get to retopology, leaving these mesh objects separate will even be helpful in some cases. In small game characters, and even in more high-res models, overlapping things like eyes, teeth, and claws are much easier to model as separate parts that clip through the main geometry. You also avoid unnecessary edge loops and polygons where you don’t need them. When to do that depends on your animation needs so play it by ear there.
You don’t need ZBrush or sculpting software to create a base mesh for retopo, you can make them in your usual modelling package by stretching and scaling primitives. If you can soft-select (shortcut key in Maya is B when faces/edges/verts are selected) it is very easy to pull forms around more organically.
If you know how to retopologize, just skip this. If you don’t consider this a crash course but far from an exhaustive tutorial.
Retopology is the process for creating new geometry from pre-existing geometry, and it’s usually done by hand for final animation-ready models. The quick and dirty idea is this: make a high-res model “live” or “sticky” or whatever your software calls it, then draw out new polygons on the surface of that high-res mesh. I assume most 3D software can do some sort of retopology, google it if you use something niche. This is what it looks like in Maya.
Maya’s retopo tools are found in the ‘modelling toolkit’ and it is done with what is called the ‘quad-draw’ tool. I keep it docked in my custom shelf, and I suggest you do the same. (hold ctrl+shift and click on the tool. This works for anything you want to add to your shelf).
Here I’ve thrown together some simple spheres and combined them into a single object as an example base mesh. What you want to do is select your base mesh, then click this little magnet at the top center of the window to make the object ‘live’. Once it’s live, we can use the quad draw tool to draw out polygons on it’s surface. Clicking on the surface makes dots. Shift click between 4 dots to make a quad. Shift click drawn quads to smooth them out. If you want to know more, google yourself a real retopo tutorial. When you finish, remember to click the magnet again to deactivate it.
Weird Texturing Technique
This is probably what you came here looking for. Our models use an unorthodox texturing method, wherein we stretched out the UV’s in ways you hardly ever see in traditional texturing. Doing things this way allowed us to texture our models using textures as small as 4×4 pixels. We kept ours at 32×32 because at a certain point the file size stopped mattering, and it was also just easier to see in photoshop, which starts adding a white pixel grid when you zoom in too far.
Those little dudes above are a bunch of our tiny textures in unity. An important note is that we set the textures filter mode to Point, which keeps the pixel-perfect color breaks clean and gives an almost vector-like quality when combined with this texturing technique.
Our UV layouts look like this. We break the areas apart and place them on their main color, then we select the faces where we want a color transition to occur and project just those faces’ UVs again from the camera view. I often will select an edge loop of UVs and use the snap to left/right/top/bottom buttons in the UV editor to create easy to see UV blocks. Then I just slide the UVs over a color break to get a stripe or edge or whatever. (on sketchfab, the filtering style is called “nearest” which is short for ‘nearest-neighbor’ which means the texture will not blur).
I’ve seen this technique in a few places, but the best example I can share is the models in Guilty Gear Xrd. Those characters there are 3D models, not sprites. They combined hand-crafted face normals and this same UV sliding technique to achieve a crisp, resolution free look. In this GDC 2015 talk, technical artist Junya C Motomura talks about many things they did that are cool. The part about UV texturing is found at 24:17.
More UV Close-Ups
Tips and Tricks
Pay attention to your triangles! If a color break edge is not where you want it, it’s probably not the Quad, it’s probably the way the triangles are laid out. Triangulate that quad and flip it if you need to, chances are that will help.
If you want to have some fun, you can even use this technique to make very low-cost stripes and patterns on things by projecting your UV’s form an orthographic camera and never actually unwrapping them.
UVs are a headache for some people, but they can also be used in clever ways when the materials you use are more simple. Obviously this technique would break down pretty fast if you tried to use it with normal maps or more complex shaders, but who knows? Maybe you can figure out a way to hack around that with multiple UV channels or some other thing I don’t know about. Take chances! Make mistakes! Get Messy!
Sketchfab has been a great place for me to learn from other 3D artists and share my works. Being able to fully navigate around models, see their wireframes and material channels has made me more aware of topology, and the community has helped myself and many others learn and connect even more. Animated models are so cool on here, and VR support is the bee’s knees. I can’t wait to see what features they come out with next. To keep up with us, check us out on our site!
Thanks, Justin! What amazing examples of game art do you like? Questions? Leave them below!