LESSON OVERVIEW
WHAT IS FOLIAGE ART?
Foliage Art is a specialized area of environment design that’s focused on creating the flora — plant life — you see in games and movies. From a single blade of grass to full-blown biomes, foliage art covers everything related to vegetation, which comes in all shapes and forms, varying widely depending on the type of media and its art style.
Responsibilities and Skillset of a Foliage Artist
Foliage artists are responsible for a wide range of tasks. A foliage artist creates leaf materials, bark materials, procedural foliage trees, bushes, grass, alien plants (if required) and collaborates closely with tech artists to accomplish weather effects like wind and snow on plants. It is also important to have a good understanding of lighting and how it affects vegetation. More often than not, when working on a game, a custom setup that describes how light interacts with plants is required , as special shading models such as Subsurface Scattering (SSS for short) are used to make plants look more realistic.
Scope
In this introduction we focus on realistic plant creation. It is important to understand how to create realistic foliage before we can move on to more advanced stylization of plants, which will be covered in later courses!
Why is Foliage Art so important?
In games and movies, foliage plays a huge role for a variety of settings. First and foremost, vegetation is used to make a world feel alive. Especially in video games with loads of immovable, static objects, plants that sway in wind significantly enhance the overall atmosphere.
Flora can also be used to cover harsh intersections, such as those created by buildings stuck into the ground, or otherwise dead looking corners. While the above image is a painting, it is visible how the artist used foliage to cover up the intersection between the brick wall and the pathway. Foliage also nicely embeds the mansion in the landscape. It creates an interesting interplay between the angular, planar, hard and sharp looking buildings, and the soft, smooth and noisy foliage.
As a foliage artist, it is worth treating any game environment like a painting. Paintings share a lot with how and where vegetation needs to be placed in a game environment.
In short, foliage is an ideal solution to cover up loose geometry, blend elements together, and make a world feel alive. Now that we know why foliage is important for an environment, we can take a look at what it is made of.
WHAT MAKES A PLANT
VIDEO GOES HERE
REFERENCE COLLECTION FOR FOLIAGE ART
If the collection of references is a topic you have never touched before, head on over to our REFERENCE GATHERING course!
Foliage specific reference collection requires finding additional, accurate information, and the process differs slightly from how an environment artist may approach reference collection, as foliage artists need highly specific types of references. Understanding what’s truly important helps avoid common errors, so let’s take a look at what we need and how we get these references.
The following example shows a case study where we want to collect references for a Sycamore Maple Tree.
Shape References
Shape References show the entire plant (in this case, a tree). We can perform a general shape reference search first to get a first impression of how such a tree looks like. Trees can look vastly different depending on where they are located. Let's not worry about locational differences for now, as we'll address those later on in the lesson.
After our general research, we want to find specific references of Sapling, Small, Medium and Large variants of the plant we are working on. This is of utmost importance to ensure we have everything needed to create a full lot of plants.
A lot is the term used for a full set or “collection” of a certain plant. We’ll dive into this later!
In games and movies, different levels of maturity are needed to add variety to the environment. We do not want to give off the impression that there are only fully grown maple trees in this world. In a natural environment — or more precisely, a biome — plants at every level of maturity can be found.
Leaf References
Our plant, whatever it might be, will likely have some kind of leaves. We need to make sure we also collect references for them. Ideally, we should gather at least the following references:
- Mature, healthy leaves
- Mature, slightly decayed leaves
- Younger leaves
- young leaves
- Leaves with heavy decay
- (Damaged Leaves) Great to show damage by bugs or even humans - good for storytelling
The following picture shows a good range of leaves, from healthy to decayed, that you can find on a plant.
Applying this to our case study of a Sycamore Maple Tree, we can come up with something like this!
Seeds / Fruits / Blossoms
Seeds, fruits, and blossoms, are important additions to plants. Sometimes it is helpful to have references of these components! While this is not always needed, depending on the season, this might become relevant.
Often, these components are needed for collectible plants in games.
Collectible plants are plants a player can interact with. They are usually used in Open World Games to provide the player with resources for healing, cooking, or crafting potions. To make them stand out from the overall landscape, collectible plants often receive additional treatment and colorful blossoms, so they draw the player’s attention.
Frond References
Frond references are highly important, and require some explanation. When crafting trees in a software like SpeedTree, we will be using a procedural generation system. These systems will be explained in a more advanced course, but must be mentioned here to understand why those references are needed.
The procedural creation of a tree will allow us to use certain "growing methods" that are common for plants. Collecting frond references will allow us to understand what type of "growing method" a plant uses, so that we can use the right settings in our plant creation software. The image below shows different growing methods in the software SpeedTree. These can be used to create different types of plants and they refer to the leaf arrangement on stalks as shown further above. The growing method is the procedural recipe that is being used to create a certain plant.
The book page from earlier in the lesson:
Using our case study, the specific growing method for a Sycamore Maple Tree, would be a Phyllotaxy - Opposite Distichous Arrangement Style.
Here you can see a Sycamore Maple Tree Sapling:
Phyllotaxy is a common leaf arrangement for many plants. As we can see in the pictures above, leaves are attached as a pair of two, opposite of each other. The next segment (or “node”) higher, we find an opposite pair of leaves again, but this time 90 degrees rotated (”distichous”) compared to the previous pair of leaves.
Frond references give us insight into the recipe of a plant. They reveal how a plant is built. We need this information to know how to replicate it. Without this type of reference, we will be lost! You will find that without Frond References, you will be unable to recreate the plant you are working on.
Bark References
Bark references are extremely important, but we must be especially careful on our reference search! We will find, when going outside or performing a google search to check out bark, that we will be presented with a wide range of bark textures, similar to what is shown above. In such cases, we need to pick what we think is the most fitting, which is often the most generic one. If you are making a maple tree, pick one bark texture for all maple trees you are making, and stick to it. If necessary, for sapling versions, a specific exemption can be made, and an additional sapling bark can be used.
Shape Reference in Winter
If you can, head outside during the winter and check out some trees — snap a few reference pics while you’re at it! Seeing a tree without its leaves gives you a super clear look at how the branches are laid out. It shows the full skeleton, which is exactly what we want to build in our software when creating a tree. There’s really no better reference than that, so grab it before spring rolls in!
General Note
Foliage reference collection really isn’t easy if we want to do it properly. We need to follow the seasons and take our references whenever possible. I always have my camera on me, so whenever I spot something I might need in the future, I take multiple pictures of it. It could easily happen that you’re tasked with working on a plant you saw two months ago, but you missed the chance to capture it. Even if you go back, it might look completely different. It could be decayed by that point, or blooming. In short — it might look entirely different because the season changed. Never miss a chance to take some quality references!
Silhouette
For everything that is being created, the most ideal silhouette should be picked. It needs to read well from the distance, be not distracting and it needs to show the characteristic of the specific plant.
If your maple trees in game look the same as a cherry tree from the distance, something is wrong. Each plant needs to contribute in their unique way to the overall biome and landscape. If we find two plants looking too similar to each other in game, they should be replaced or one should be deprecated at least.
The uncanny valley should be avoided.
Do not create foliage that is looking overly awkward if there is not a specific case for it. While the tree in the picture above does exist, it is not a good candidate for a foliage asset. The reusability is significantly reduced because of its distinctive look. Repetition is the result of this if such tree was placed next to each other. For many other obvious reasons, such design choice is questionable.
BIOMES
We have so far taken a look at how to work with single plants, but they all serve a purpose. This purpose is often being part of a larger biome. Let us take a look at what this means and how to work with biomes and the concepts of designing them.
Design with Intention
To choose plants intentionally and ensure they enhance a biome (a type of environment that has a specific type of climate, terrain, and vegetation) in a meaningful way, we first need to understand how game biomes are constructed.
A good starting point is to look at how vegetation is distributed across a landscape in a believable manner. In games, this is often done through the use of landscape textures. These textures — grass, gravel, dirt, and others — form the foundation of a terrain. Typically, we want grass foliage to appear on areas textured as grass, while gravel or dirt may call for different vegetation or none at all.
This connection between the landscape texture and the 3D foliage growing on it is essential for creating natural-looking environments. A deeper dive into this concept can be found in the Biomes course (link).
Top-Down perspective:
The image above illustrates a classic scattering ruleset commonly used in games. This is a simplified representation of such a system. Imagine each primitive in the image as a container for plants. Where you see a box, there could be a larger bush or a small tree — or even a group of plants arranged together.
Think of these primitives as data points that define where specific game assets can spawn. A single spawn point doesn’t have to generate just one plant; it can spawn a set of plants, as shown below. It’s up to the artist to decide which plants appear and how many are placed at each data point.
Each of the assets above contains more than one plant. These are pre-composed arrangements that can be scattered around an environment. Such assets are usually carefully curated to balance optimization with strong composition.
Returning to our data points, the stretched spheres represent the largest components in a biome — typically the biggest trees. These form the Emergent Layer and Canopy Layer of the biome, in this case, a rainforest.
The boxes represent data points that spawn understory foliage.
With the ruleset shown above, understory foliage spawns close to canopy foliage. This makes sense, as plants tend to cluster together. It’s common to find smaller plants near large trees — sometimes because they benefit from the tree’s resources, or simply because they thrive in its shade. That said, there are cases where the opposite applies. For instance, grass often does not grow in the shade of a tree. In such cases, the spawn points are configured to avoid placing grass near trees.
Finally, the cones in the image represent forest floor plants — small bushes, twigs, and ferns. In many cases, additional scattering systems exist to populate these layers independently from tree placement, adding further variation and realism to the biome.
GROWTH CONDITIONS
Working on foliage means knowing how plants grow and how they adapt to their environment. Foliage and the environment plants are located in, are tied together. The better we are at linking the environment with the aesthetics of plants, the more believable our environment will become.
A certain type of weather can influence the growth of foliage significantly. In the example shown above, constant directional wind in this environment has deformed the plants and forced them to grow in a certain way. Just from looking at this windswept tree, we can grasp how it feels like to be in this environment as a player. Implementing such an asset in the right location can enrich the overall player experience.
Similarly, we need to think about seasons. When looking for references for plants, different pictures from different seasons can be found. If you collect your references in summer, plants might look entirely different compared to going out for a reference trip during spring. It is important to know which season the foliage should be created in, so only relevant references are being collected. Furthermore, a distortion of seasons can be used to draw attention to a certain type of asset. It is quite common that Cherry Trees are shown in their beloved pink blooming appearance that in reality only lasts for a few weeks. Afterwards they loose their unique identity. Even if other plants are shown as if it was summer, an exemption can be made in certain cases like this, to put emphasis on a specific plant and to show it off in their prime state. These decisions should be made intentionally, as players will notice if things fall apart caused by bad design choices.
Showing other types of growth conditions like signs of ageing or infestations, like trees which are being strangled by ivy, are a great way of selling plants to the player. It makes the world feel alive and changing. At this point, a tree is not just an asset that does not interact with the environment, it becomes part of it and is being influenced by it, in a negative or positive way. Adding lichen to trees in damp areas for example really shows that the foliage is changing based on their location.
PIPELINE OVERVIEW
VIDEO GOES HERE
Photogrammetry versus Traditional Workflows
Generally, there are two ways of creating a plant. We can use procedural plant creation tools to get the job done, or we scan the plants ourselves.
Only very rarely, an entire plant is being scanned and used. In most cases, when we talk about photogrammetry, plants created using this method only use scanned components. These are usually leaves which are being scanned. This can also be a bark texture or branches, as well as entire tree trunk sections which are glued together with procedurally generated tree parts.
Scanning plants has the advantage of them looking photorealistic, without any artistic work needed apart from some minor adjustments. However, this technique can only be utilized on projects with a realistic graphic style and making edits to the plant becomes harder, as they may or may not be created in a procedural environment. There is also little chance to expand a dataset of images after the trip. We need to use what we have got. There is no way to go back in most cases. Some game studios would make trips to volcanic islands to scan some highly specific foliage and rock embankments there. They spend quite some money on getting a full expedition team over there. After they come back, there is no chance to go back to the location and take additional pictures.
In contrast, plants can be created using procedural software, like Substance Designer for leaf creation and bark textures, as well as SpeedTree for the actual plant creation. This has the huge advantage of being highly flexible with design iterations. Creating plants in different art styles is also entirely possible with ease. The only downside for projects with a realistic style is, that artists have to spend quite some time to achieve realistic results with the tools they have, while mother nature will always do a better job at doing so.
Therefore, in most games with realistic art styles, a mixture of both workflows is being used to allow for the highest amount of realism while still being able to iterate quickly, using procedural workflows.
VARIANT CREATION
As foliage artists, we always want to create a set of a particular plant, rather than just a single version. These sets are often referred to as a lot.
The image above shows different plants, each with their full lot. A lot typically includes at least three variations — such as large, medium, and small, or young, mature, and decayed — but it can easily include more.
Sometimes, a lot might include a compound asset, a single mesh made from an arrangement of multiple plants. Here's an example of one:
These compound assets are usually created last, after all the individual plants in a lot are completed. These grouped assets are mostly used for faster placement in the engine, especially when filling large areas. Instead of manually placing hundreds of small assets, a few compound pieces can do the job. This saves both time and performance.
In real-world terms, you can think of this arrangement of Monstera plants as a lot as well!
Just like the example above, our goal is to cover a broad visual range for any given plant type. A good starting point is to create small, medium, and large versions. But depending on the plant, you may need even more variation. For example, trees often have extra variants like sapling, decayed, leaning, dead, forest, or field types. A complete lot can include a wide range of looks for the same species.
💡 When working on a full lot, it’s usually best to start with the most complex specimen first. That way, you’ll establish all the textures, materials, and mesh details up front — basically creating the full recipe you’ll need to simplify and build out the rest.
💡 If a foliage artist asks for 3 plants to be created, that usually means additional variations of each plant are needed too. So, right from the start, it’s important to know that this kind of request typically means you’ll be making at least 9 unique assets!
PERFORMANCE LIMITATIONS
When working on foliage, performance is key. Plants often fill the entire screen when walking through a forest, meaning a large portion of your performance budget goes toward rendering them. To keep things running smoothly, you need to be mindful of how many plants you use, their level of detail, and your use of transmissive material properties.
Leaves usually use a translucent shader model which features options for Subsurface Scattering on leaves. These shaders can become quite performance heavy and need to be used and optimized carefully to maintain quality.
Beyond the number of assets, it’s also important to manage the detail level of each individual mesh.
The image above shows a plant modeled with different polygon densities. You shouldn’t add extra vertices if they don’t contribute to the asset’s silhouette. For example, removing just 4 polygons from a single grass leaf can save over 50 polygons per grass mesh. Multiply that by 200 grass meshes in a scene, and you save over 10,000 polygons — a huge boost in performance.
Now, that we know what foliage art is about, how to look for references and what to look out for when creating plants, we can move on to create our own plants.
