THE WAY TO CREATE VEGETATION FOR VIDEO GAMES. THE BLACKSTEINN EXPERIENCE

In our new article we decided to tackle a topic that doesn't come up that often. It is the development of trees, bushes and flowers for video games. You have to agree, the height of spring is the best time for a text like this.

Blacksteinn artist Anastasia Goloshchapova shares her working methods, software secrets, and various tips and tricks in detail. The story that follows will go on her behalf.

Enjoy reading!

A LITTLE BIT ABOUT THE NATURE OF GAME GREENS

Plants are an important visual component of any game. The foliage is not just a part of the environment. Plants add vibrancy and variety to scenes, and are also an element of narrative and storytelling, carrying information about the location. With this the player can be given visual clues as to what awaits him in each particular level.?

With the development of CG it is possible to improve the digital plants. Now, instead of monotonous undetailed objects, artists can create biomes for every taste: from realistic trees to alien flowers.?

Of course, the subject of foliage is very broad, and there are countless ways to create vegetation. As in any activity, the technical requirements vary depending on the project and the customer's wishes. Software can also be used in many different ways. In my work I usually use ZBrush, Photoshop, Substance Designer, Marmoset Toolbag, Quixel Megascans libraries, and, of course, SpeedTree.

In this article I will tell you about the most interesting, in my opinion, way - combining the mash from SpeedTree with the base, sculpted in ZBrush.

HOW THE WORK IS BUILT

So, His Majesty Pipeline... As always, everything starts with the search for references. Usually the client sends the studio only an example of what he wants to get in the end. Therefore it is very important to spend time on finding additional materials, and the more and higher quality they are, the better. Also it will never be superfluous to search for references in the real world: it is always important to look around, notice details, interesting textures and, of course, photograph it all. Such photos can save you a lot of time during the texturing phase.?

Sculpting

Once enough refs have been collected, the sculpting process begins. In ZBrush we sculpt the base - the part of the tree that will be closest to the player. With ZBrush we can make a complex shape with an interesting, unique texture - and according to customer requirements, of course.

At this stage it is important to work out the artistic component of the model. It is not necessary to strictly copy the reference. The main thing is that the object looks whole, harmonious and in general looks like the tree we "need".

Sculpting of natural objects differs from creation, for example, weapons by absence of strict geometric forms and obvious symmetry. But we must remember that growing in the wild may not always be pleasing to the eye due to various factors: wind, snow pressure, growing a tree on a sloping piece of land, and so on. And the artist's job is to make an object that looks both organic and pleasing in the game. Therefore, it is important to maintain a balance between the naturalness of the model and compositional appeal.?

Low poly + UV

When High poly is ready, we move on to retoping and mapping. The principle here is the same as with any other model, so I don't see the point in going through these steps in detail. The main thing to remember is that all the shaping elements should be "beaten off" on the HP and LP, and the final LP should match the HP as much as possible. You should try to minimize the number of shells on the mapping, and hide the seams.

Bake

If you follow the above requirements, it should be no problem to bake the maps. Otherwise, the main thing is to stick to the standard rules of baking. We have written about them in detail in our previous articles.

Creating Textures

Note: All basic materials must be assembled before you start working with SpeedTree. So after baking we move on to textures.

There are also a lot of nuances here, which depend on the project and the customer's wishes. If we are talking about the creation of realistic plants, the Quixel Megascans libraries are of great help to us. However, the finished material from the libraries is not everything. In order to get a unique texture, it has to be modified, and some interesting details added. This is usually done with the help of Photoshop.

If the library doesn't have the material you need, you can use a photo. In this case you need to remove the unnecessary glare, do color correction in Photoshop, create an Opacity Map if necessary, and bake a normal map, on the basis of which Substance Designer can create other maps, like AO and Roughness.?

The first thing we do is to drop the LP into the Speedtree, put a texture on it - the texture of the LP model must be a tiled one. Using the Photogrammetry tool (Texture Blender Extension), we start extending the main trunk to our sculpted stump.

This tool allows you to discreetly connect several mashes to each other, resulting in a unique and yet easily editable object. But the main thing to remember is to leave a small margin of geometry on the LP, so that the tool doesn't eat up the sculpt.

The next step is to add some branches. They should be a smooth, natural shape. The closer the branch is to the player, the higher its resolution should be.

Thin branches in the crown of the tree do not make sense to make geometry. That is why they are usually created with clusters. You can use ready-made ones from the library. However, if necessary, I make my own in SpeedTree. It's easy: in the front projection we create a branch with the necessary settings, and in the Export Material tab we set the settings for the necessary maps. Then we just press "Ok" and the custom cluster is ready!

Leaves, for the most part, are also made in clusters. So, it's possible to create a three-dimensional spreading tree and save a polycount at the same time. Keep in mind, however, that you shouldn't forget the individual leaves. They will add variety and dilute the uniformity of the clusters. When the wind "interacts" with these leaves, the animation will be more realistic.

And now our tree is almost ready. All that remains is to make minor artistic tweaks and, if necessary, to fit the model to the reference.

By the way, artists often have to resort to various tricks to save resources (not only technical, but also time). For example, the same tree can be used several times depending on the location, just from different angles. In this case, it is important to avoid excessive asymmetry, so that the copies are not so obviously conspicuous. SpeedTree also has a very useful tool called Randomize. It allows you to generate different variations of the plant with the click of a button.

Any kind of plant can be created based on the above pipelines. As for small trees, bushes or flowers - do it directly in SpeedTree, ignoring the sculpting step.?

TO SUM IT UP

And at the end, a few quick tips on what you should always keep in mind:

• Figure out the interface. It sounds like a given, but in some places the SpeedTree interface is not very obvious. So, to make your life easier, it's best to read the official documentation?
• Remember that the SpeedTree node tree must be as small as possible, otherwise it will complicate the work and editing of the model.
• Try to make everything as procedural as possible. Don't overuse manual editing tools, at least for the first time
• Keep an eye on your polycount and spread it evenly over the model