Kim Aava summarized her amazing talk about the difference in techniques, which artists use to build photo-realistic and stylized environments.
Kim Aava summarized her amazing talk about the difference in techniques, which artists use to build photo-realistic and stylized environments
Introduction
My name is Kim Aava and I’m a 3d Artist specialized in Asset and Environment Art. I studied game design at Campus Gotland, part of Uppsala University in Sweden. After 3 years and graduating with a bachelor degree after which I studied 3d art at a vocational education Futuregames for one year, in Stockholm, the city where I also grew up in. During my training at Futuregames, I have also been involved with The Solus Project, helping out as an Environment and Prop Artist. After my training, I moved abroad and had the honor to be an Asset Artist on the game Horizon: Zero Dawn at Guerrilla Games in Amsterdam. Later I moved back to Stockholm and started working at a VR-studio, Fast Travel Games, with the recently announced VR-game title Apex Construct.
I recently held a breakfast talk organised by Women in Games and hosted by DICE during the beginning of November. As I have experience working with both Realism and Stylized art, I found myself interested in the differences in execution and approaches in the different styles when creating game art, hence the name of my talk Realism vs. Stylized. Seeing as a lot of interest was shown in my lecture I thought a breakdown would be nice for everyone who couldn’t attend. So together with 80LEVEL, I have made a small summary of what was covered during that talk.
Realism and Stylization
What do we mean when we talk about Realism and Stylization? It can seem quite obvious, realism refers to realistic graphics mimicking lifelikeness. It doesn’t necessarily need to exist in the real world but be conveyed as if it would belong in our world. What we believed to look realistic 10 years ago doesn’t today, for some, it might even look stylized because of the choices made to deal with limitations in technology.
A good example is the Uncharted games, if you compare their first game released 2007, 10 years ago and the one released this year, 2017, you can see how the visual and technical quality differ a lot. Their lead protagonist (as shown in the example) lacks a lot of details back in the days, details we can afford and also emphasize with modern technology. Examples of details that have improved are the skin and clothing, the wrinkles in both as well as shading. 10 years ago PBR didn’t exist for game development but is quite significant in today’s process for games art creation. What we believe is realistic today, will not be in 10 years. And yet, we keep saying that it never looked better and it will be hard to make it look even more realistic in the future.
In the picture above, you see some games that have been released quite recently and gained a reputation for their realistic graphics. What makes games such as Horizon: Zero Dawn, Uncharted 4 and The Witcher 3 look and feel realistic? One might even argue that the graphics are enhanced realism. What I mean with enhanced realism is that the colors, light, and atmosphere are more vibrant and has the perfect weather and lighting condition compared to what you would see in your everyday life in a similar environment. Like with movies and photos, post-process and enhancement are used to create a more interesting scene and feeling. Real life can be quite dull and boring to look at and a movie, photo or a game wouldn’t sell very well if it didn’t look inviting enough. So what we as artist mimic when it comes to a realistic graphic is typically an enhanced reality with the perfect scene, color, lighting, and atmosphere; in order to craft something that would appear to the player as though it belongs in our reality.
Stylized game art has also changed because of these new allowances in technology. From being limited with low-poly and solely using diffuse map inputs only, to pushing high polycounts and access to shaders and materials, stylization can now flourish.
The methods might seem similar, but due to the loss of restrictions their end results now truly differ. The significant difference between realism and stylized is that with realism you are restricted to making things look ‘real’ while enhancing their visual language. With stylized you are free to play with the shapes and colors, exaggerate or remove details to enhance the look and feel in any direction. Doing so with realism would break the illusion of reality as it wouldn’t be viewed as what we perceive to be as ‘realistic’, it would not belong in our world.
In conclusion, you could argue that realism is a stylisation in of itself and that nothing is truly realistic, but manufactured to appear realistic within today’s technological limitations.
Challenges of creating stylized graphics
The challenge of stylized game art is conveying to the player what the assets, environment, and characters are typical with fewer details and put emphasis on the shape, color and form. Everyone knows what a birch tree looks like, you have probably seen one in real life, a movie or a photo. You can only imagine what a stylized birch tree could look like and this will vary widely depending on the pursued style and artist.
Stylization refers to a visual depiction, which represents an object without a full attempt and accurate representation of an object’s realistic appearance. This can include simplifications in shape, lines, color, pattern, surface details, functionality and relationship to other objects in a scene. Which is why stylization is most commonly used to describe an art style that has more cartoony features than a semi-realistic style that usually adheres to realism in details rather than simplifications. As stylized graphic are so varied, there’s no single set of guidelines in creating an art style for games. I divide stylized game art into two categories: Over-exaggerated stylization and Minimalistic stylization.
Over-exaggerated Stylization is a play on shape and silhouette, the focus is on larger details and shapes rather than small details and microsurface details that are common in games with realistic graphics. In this style you exaggerate the shape of an object, you might enlarge it or remove a detail depending on the importance of what the asset is supposed to convey. Examples above of over-exaggerated stylized game art are from Ratchet and Clank and Overwatch. Both games tend to put emphasis on objects by enlarging smaller details.
Above is an example that explains the thought process of when to choose to either emphasize an object and when to remove it. The above example is an electrical line. The object consists of wooden beams and are usually the iconic shape of the object. In addition, it has small cylindrical insulators (marked in red) connecting the lines with the pole. To be able to translate the function of the electrical line is it important to keep the insulators in order to convey its usage or would the player recognize its purpose without the insulators? Is it important to tell the story of the object or would it look silly and too much like something else if I would emphasize the scale and shape of the object? These are all questions I ask myself when looking at references when creating both realistic and stylized assets, but even more so when it comes to stylization as we aren’t trying to achieving the lifelikeness.
Another aspect to consider is how far away the object is from the player, these are meant to sit high in the sky, you might not even spot the insulators if it’s that far away. You would be able to translate the function of the electrical line without these small devices. If the object is closer to the player, it might be a nice detail to add the insulators to the object to give it a more interesting silhouette and to break up the wooden material in the object. There’s no correct answer to how the final electrical line should be represented within any style, though it’s important to keep consistency in your choices for assets belonging to the same world.
Minimalistic Stylization is comparatively flat compared to Over-exaggerated Stylization, it plays on simplicity. With very few details in both color and shape, you try to convey the purpose of the asset and its function. It’s usually stripped of all medium and small details, lacks normal map inputs and usually only uses a color map. The above picture shows two games, Firewatch and The Journey that would be in the category minimalistic stylization. As in the example pictures from Journey you can clearly see that the ground is sand even though it’s just a uniform brown-orange color. You can also see the rock formation in the background because it has the rough shape and silhouette of a rock and is supported by the surrounding environment, you will recognize it as a rock pillar in a desert without the need of further details.
Sculpting
For both stylized and realism, I start by analyzing my references, before doing any sculpting. To show an example let’s start by analyzing a simple object such as a Mandarin. A mandarin is a fairly simple asset without a complicated silhouette, therefore a good starting point in analyzing an object before moving on to more complex assets.
When looking at the reference picture I tend to look for larger shapes first, then medium, small and microsurface details. What are the characteristics of this asset? What would differentiate a realistic one from a stylized one is the detailing and texture? Defining the characteristics of an asset helps in the creation of both a realistic look and stylized look. By pinpointing the required details you are able to recreate them to mimic life likeness but also to know what details that might be enhanced or changed in stylization.
Based on my analysis I created a quick example of a mandarin in both realistic and stylized variants. You can see how they still use the same oval-round shape, but a bit uneven as it is an organic fruit. It has skin wrinkles from the top where the branch touches the root (green top of mandarin). A mandarin’s microsurface details are noisy, with small uneven bumps which helps it gain an uneven texture that causes light scattering against the peel and makes it look rough. Seeing as the bumps are an important feature of a mandarin, for a stylized asset I would keep a few in and enlarge them, this will also help in making it look less like an orange tomato which lacks the surface details and is more glossy. You will need to look for overall shapes and details that would convince the player of what type of object that they are seeing regardless the style you are using.
Silhouette
The silhouette is very important for any object, for simple assets such as a mandarin to a more complex shape as a wooden stump or for characters such as a pirate captain with their wide-brimmed hat. You must be able to recognize an object, even with objects that are supposed to be of an unknown origin, they should from the start be identifiable when seen.
For the talk on Realism Vs. Stylized, I made one asset in two different styles. One realistic wooden stump and one stylized to show my approach to shape, silhouette and details when working with the different styles. For the stylized approach, I chose to go with the over exaggerated stylization as minimalistic stylization would probably not had required a sculpted version of the model.
Starting off with sculpting, I divide the different level of detailing in the asset in sections. Listed from large details before diving into the microsurface ones, namely; Silhouette and large shapes, medium details, small details and microsurface details.
Silhouette and large details. Defining the silhouette of an asset is the most important when you start sculpting. Looking at the larger proportions, the silhouette and overall shape, there is a small difference between the realistic and stylized asset. The realistic stump has in some areas a more organic or wobbly feel than the stylized one, particularly in the bottom I added more straight lines. While sculpting the large shape and silhouette it is important to make the object recognizable and just work with the shape of the asset. It’s also easier to correct and adjust larger shapes before you dive into details. Say you would start detailing first and spot an issue with the shape of the asset, it will be harder to correct as detailing requires a higher amount of polys.
Medium details. Are smaller shapes that affect the silhouette but does not create the base silhouette of the object, as seen in the example above. These shapes also that require a few more polygons than the initial shaping of the main silhouette. In this example, the medium details are the splinters on the top of the stump where the rest of the tree trunk has fallen off. It is important to think of how the splintering happened when the rest of the tree trunk was ripped off. Did someone saw it off? Did it fall, which angle did it fall from? Etc. If it would have been sawed off, the stumps top part would look quite different. It would be flat and a straight line, the inner wood would have seen marks and little indication of tearing.
The splintering and unevenness are present in both realistic and stylized asset but has been minimized and simplified in the stylized version to avoid the noisy feeling and to keep it clean. While the realistic one has more small “teeth” and jaggedness as to mimicking the splinter look of a real-world stump.
Small details. Refer to parts of the sculpt that don’t change the overall shape and silhouette, it shapes the characteristics and the surface finish of the object. The bark is a characteristic of a tree, it could either be present or be naked wood. There are different types of barks, which also plays into the shape of the medium detailing of the splintered wood regardless if present or bare wood. The strips of the bark on the stylized one are larger, as this is a characteristic of the wood stump, these details were not removed and instead exaggerated.
The wood eye and the hole are in this case not impacting the silhouette and are therefore considered small details. The wood eye is an end piece that connects the trunk with a removed branch that has been either cut or fallen off, the size of the wood eye indicates the proportions of the absent branch. The wood eye and the hole are in this case not impacting the silhouette and are therefore small details. Seeing as the wood eye is of a fairly small size that is far down from the trunk, it was probably fairly fresh when it was cut off. Branches tend to be larger on the bottom trunk if not removed than on the top. Consider details such as this when thinking about your asset.
For the hole, there is not much difference between the two, the shape of the stylized asset is straight to fit in with the rest of the angular style of the bark.
Above is a close up of the wooden rings of the inner woods. The wooden rings show the age of a tree, seeing as the bottom stump is a quite thick one could assume that the tree is quite old, therefore adding an amount that makes sense for it. In stylization, this is harder to show and play on since adding a lot of rings would make the surface too noisy and grainy. For the stylized one, I left out the smaller rings and only focused on the larger area, adding only larger lines to make out the ring shapes.
Microsurface details. This detailing pass is the last one to be added since it does require a high amount of polys. Before adding microsurface details, all major (and minor that can be spotted) issues should have been adjusted, since beyond this section it will be hard to make major tweaks to the model with ease.
In general, the microsurface details refer to adding surface noise such as flakiness in bark, rust surface, small cracks etc. In these wooden stumps, the realistic bark has more fiber structure, with flaky pieces on top of each other which creates the fiber structure surface. To avoid a surface with a lot of microsurface details for the stylized one, the bark has larger shapes and no surface noise such as flaky features added to the bark.
As the previous example with the mandarin, the small spots on the stylized one could either be microsurface details or small details depending on the size and impact on the model. A crack can even be a large detail if it changes the shape or silhouette in an asset. When looking at your references it’s important to divide the asset into categories such as the above examples and identify what in the assets that are large, medium, small and microsurface details, to help you in the process of creating an asset. Start with larger shapes and end with smaller details, this might seem obvious but is a common mistake made by artists in general, especially when getting too focused on certain areas of an asset than the asset as a whole.
As a final comparison below you can find the end result from the baked highpoly object. The UV layouts have not been optimized for in-game use, instead, the uv-islands have been made to match each other to better compare the details of the two stumps.
Texturing
A stylized object seems to have fewer details and larger shapes, which would imply it’s easier to create and texture for. Old hand painted styles required light and shadow information painted into the color to avoid the need for normal and specular map input, this technique also conveniently saves memory in lightmap resolution. Adding light and shadow to the color input was necessary due to the limitations in technology and affected the execution of the game art. With new methods such as PBR, the work methods for both realism and stylization becomes quite similar, as PBR sets the guidelines for the creation of textures and materials. While it was common to add distinct light information in old hand painted and realistic texturing to create shadow and highlights, in PBR you have a flat color input for albedo with no light nor shadow information, regardless of the style of choice. Therefore as the procedure to create the textures for the stylized asset is neither easier nor harder than realistic textures as the guidelines and execution for PBR are the same regardless of style choice.
The picture above is a render of the final textures with light information. The final meshes do not have any special shader, they only use the base input Albedo, Normal, Gloss, Specular and Ambient Occlusion. This is to demonstrate the basic principle of modeling and texture without the need for advanced inputs complicate the documentation of this documentation.
The above render showcases the same wood stump, but with only Albedo input and an unlit material. Most of the medium, small and microsurface details are only visible through a viewport with scene lighting due to the light information and depth from the normal, gloss and specular input combined with the light source, which is lost when removing these inputs.
As mentioned earlier, in PBR you leave the albedo flat with only color information as highlights and shadows are added by the rendering engine. When comparing the albedo maps it’s noticeable that I added highlights and shadows to the albedo for the stylized wood stump. In stylization, you are free to enhance details such as adding highlights and crevices in the texture to place emphasize depth. This is a style choice and you shouldn’t be afraid of experimenting by adding details as long as it won’t break the lighting when placed in the scene. PBR serves as guidelines and is not by any means set rules, there are different methods for PBR and the input varies in all engines. It’s easy to forget that these are not set rules, and as an artist, you have the artistic freedom to enhance and emphasize elements in your work.
Below are albedo maps for both the stylized and realistic wood stump to offer a better overview when comparing the texturing methods for both assets.
I tend to use a curvature map on roughly 5% strength and overlay in a brown color to add a bit of dirt to crevices in order to highlight added depth in the mesh. This might also seem contradictory to the flatness in albedo but, as mentioned earlier, we have the liberty to enhance details in our creations, within reason.
The two pictures above are renders of the same assets in different lighting. This serves as a comparison between the stylized and realistic one in different lighting conditions and also to be able to view the effect of the emphasis made in the albedo. The added highlights and darkness in the crevasses of the stylized stump do not affect the shadow casting from different directions negatively. Same with the realistic stump, the added brown color in the crevasses doesn’t affect the shadow casting, though it enhances the details of the bark when in dull lighting conditions. But when too much highlight or shadow is added to the albedo it might break the shadow casting and not be reusable in various lighting conditions, which is the purpose of using PBR to begin with.
Advice
Make sure you figure out your references before starting, make a breakdown of the asset, environment or character before going into the block out or modeling. List and draw in a document the large, medium, small and microsurface details. This is equally important regardless of style to make sure you capture the essence and core of the object. Doing so will be helpful throughout the whole creative process as you have already decided on your guidelines, reducing the interruption in your workflow and analyzing details that you might not have been aware of that were important. For a stylized project, it’s also important to establish if you aim for an exaggerated or minimalistic stylization. The decisions in style affect the silhouette and also how you will treat the details in the asset.
As a final conclusion, remember that there are no correct ways of creating assets for neither realism or stylized, what matters is the end results; how successfully you managed to communicate the core and essence of the assets in the game to the players.