Urban Abandoned District: Making UE4 Content for Sale with 3D Scans

Adam Jarosz and Michał Mierzejewski discussed how they plan and create modular environments for the Unreal Engine Marketplace using photogrammetry.

Introduction

We are Adam Jarosz and Michał Mierzejewski, together we founded the Scans Factory studio. We create scenes for sale on the Unreal Engine Marketplace as well as do art outsourcing for various projects. Due to the fact that we are interested in the realism of our scenes, we put emphasis on working with 3D scans. As we mentioned in our last 80.lv article (Photogrammetry in Environment Design), we have been working together for several years at The Farm 51. For about two years, we built our side project after hours and it actually turned into a small studio.

Working in a two-people team gives us wildly more creative possibilities. For the past few years, we have been planning and collecting materials for something bigger. We hope that now we will get an opportunity to implement some larger and smaller ideas.

We started working full time at the beginning of 2021. And we have lots of plans for great challenges. Keep fingers crossed!

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Urban Abandoned District Scene: How It Started

Adam: Being able to create unique scenes means a lot to us. Every time our starting goal is to take our quality to the next level.

I start building an idea for a scene by collecting references and saving them on the Pureref boards, miro.com, and as Facebook bookmarks. What is also interesting in our case, I browse our scan database. Our collection has way more materials than we are able to process, and it would be unwise not to use it.

When we want to build maps relying on the scans we do not have yet, the natural first step is to use Google Maps to walk in places we have good access to.

When I have the initial vision of what the level should look like, I start testing some ideas by blocking the scene in Unreal Engine 4. Sometimes I use regular boxes and sometimes – a decimated version of our RAW 3D scans if they already exist. Our blockouts can be called 3D concepts of our locations.

A minimum plan for the location is also created, although it usually grows twice as big in the end. Effective reuse of assets is also important to us because of the texture overhead that the scans have. The modular approach is our friend, too.

We talked week after week about the direction of our scene. Comparing the screens from the entire process helps us really judge our progress. Fortunately or not, both of us pay a lot of attention to details and help each other to polish our things all the time.

Planning Packs for the UE Marketplace

Adam: During the entire production of various packages, we collect references for the next scenes. Before selecting a new one, we first review these ideas and our database of scans.

The second step is to correlate each plan with the needs of the UE Marketplace. We choose an idea that in our opinion will be useful to the community and will match our style. Sometimes, we get some questions and suggestions from the community, like with the interiors for the Abandoned Factory Buildings project. First, we released a free update of the original content and then expanded this idea into a new package.

When you are a Marketplace artist, a good practice is to work in one of the older versions of the engine (at least a year older) to support creators more widely. Technically, there is always an opportunity for us to jump over several versions and take advantage of the new features. For the Urban Abandoned District package, for example, we did that to set up lighting.

In addition to that, we constantly improve the quality of our scans by investing in new equipment. In Urban Abandoned District, the textures are several times higher in quality than before and the accuracy of the geometry, in our opinion, has reached next-gen standards.

When working with the scanned ground textures, our pipeline starts with scanning 10-20 samples that should suit us. Then we test how they work and blend in the level and only after that, we choose the best 3-4 to prepare for the final scene.

Modeling

Michal: Because we create our scenes for the Unreal Engine Marketplace and want them to be most useful for the community, we try to make them in a modular way. When we scan a particular object, we immediately think about how we want to separate it into many elements so that it is easy to build a scene.

To save memory budget for textures we use mirror geometry for the other side of the model. We create tiling materials not only for the landscape but also for walls, which, when placed on simple objects, help to build an environment. All this allows us to reuse content more easily to create a large level.

Sometimes we even scan entire buildings with interiors to create specific prefabs. Thanks to them, you can quickly build a level. We decided to take such a step because in the previous pack (Abandoned Factory) there were a lot of requests from the community to provide the whole building structure. To use the model efficiently, we prepare separate elements of such a building and create variations.

In our work, we use several software solutions to create 3D scanned models, but in short, our workflow looks something like this:

If we need to optimize models, manual retopology gives us the best results. It is also the most time-consuming method, but it gives us full control. Correct topology allows us to easily create new variations or LODs and extract fragments to create additional models. But in some situations, simple decimation and a bit of manual tweaking produce great results.

Texturing

Michal: Since our team is so small, to be able to create so many models with realistic textures, we focused on the use of photogrammetry. We have a lot of experience with it from previous projects, and we have been using this pipeline in our work since 2014.

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Based on real 3D scanned objects, we get a wear-and-tear look quite naturally. Of course, it is sometimes difficult to find an object that perfectly matches our expectations. This is the reason why we carry DSLR cameras almost everywhere – we never know if we are going to find something interesting during a walk. While working on a scene, we are looking for real locations from which we can take the best scans. One time we do it from the office, browsing various urbex pages and groups on Facebook, another time we get in the car and drive to the place we chose on Google Maps.

Most of the common-use assets such as pipes, metal beams, etc. are UV mapped to the existing scanned textures. This allows us to save memory for textures and stay consistent.

Depending on the size, models are sometimes split into several textures according to the UDIM workflow. It is about keeping the right pixel ratio of objects in relation to each other. In the case of a building, we assume that the real 2.5x2.5m section of a wall has one 4096x4096 texture.

Texture example:

Of course, the textures produced with photogrammetry may have problems like holes, ghosting, or blur. I make corrections in Photoshop and Substance Painter. Recently, Substance added the functionality to work with UDIMs which is a huge improvement for the pipelines that involve using 3D scans. Now we can easily make corrections or add entire fragments of textures based on Smart Materials. The same applies to working with an RMA mask or a normal map; sometimes the color texture is taken from the scan and the mask and normal map are based on Smart Materials corresponding to the surface.

When working with normal maps, we also mix the normal map from the scan with the generated normal map from albedo. This allows us to add extra micro-detail to the surface.

In addition to that, we prepare special masks to easily edit the color for different versions of the same model.

Vegetation

Michal: I always wanted to deal with foliage and it was something that we missed in our scenes the most. We've seen a lot of environments with vegetation made with our assets, and that need for foliage was especially visible there.

Since we make scenes for the Unreal Engine Marketplace, we can’t, unfortunately, use such great tools as SpeedTree (due to the license conditions). This is the reason why our pipeline looks different and includes several programs in it.

To create the textures, I used the "light scan" technique. This is a method used to estimate surface normals by illuminating the scanned object from different angles and taking pictures. It's quite fun walking around with secateurs, collecting grass and branches and bringing it all into the studio to take pictures.

This way, we get the albedo, normal map, and alpha texture in ShaderMap 4. Then I made atlases in Photoshop from the prepared textures. Based on that, I started modeling in Maya. The entire process involved many steps back and forth. Finally, I created the wind effect with manual vertex color painting.

Adding a lot of different vegetation into the Urban District scene helped us make it feel even more abandoned.

Lighting

Adam: As mentioned earlier, it was thanks to the switch to the new version of the engine that we could fully support the lighting scenario. It allowed us to work independently on two completely separated setups, post-processes, and reflections. This, combined with the base materials, also allowed us to quickly come up with an optimal material setup that worked in different lighting conditions.

The night scenario, above all, is aimed at demonstrating that our scans can easily cope with very different lighting conditions. Moreover, it perfectly reflects the atmosphere of walking in a half-abandoned district. The silence is broken by a barking dog, a wailing siren, or buzzing fluorescent lamps. We also added a flashlight to reinforce the feeling.

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Of course, the physical behavior of materials is much more difficult to obtain with scans, and we relied heavily on histograms and our experience in creating materials. We leave a lot of micro-details of the shadows on textures to retain believable depth. We can also recommend using roughness out of the albedo in the base material, we believe it allows us to ultimately achieve much better visual effects. For example, in terms of efficiency, you can save 20-30% of space occupied by the roughness, which can be used to increase the resolution of other elements. It works for more than 90% of our textures without any noticeable difference. When people create scenes based on our scans, their models match ours so we believe this method is effective.

Most often, our projects rely mainly on static lighting, so it requires frequent lightmass recalculation. This is what allows you to get that soft lighting. Although you have to wait a few hours for the final render, in our opinion it is still the best solution for most real-time projects. This allows us to run this map in 60-70 FPS on GTX 1070 even though we do not implement hard optimization.

Reflections are baked into reflection captures. There are actually quite a lot of them in our scene, over 80. They should be carefully placed in order not to harm the performance. We want our maps to be truly game-ready.

However, if you have a chance and no limitations, we recommend running our map with RT because it looks amazing. We offered the community to create an RT version of the scene and soon the results should appear on our social media.

Challenges

There were many challenges, but juggling a full-time job and our own company was definitely the most problematic one. We worked mostly in the evenings and nights for many months. There was no way of continuing that, so we were forced to leave our previous employer, The Farm 51.

If we were to name any of the challenges related to the Urban Abandoned District scene itself, it would probably be vegetation. We avoided doing foliage for a long time because there are companies and people on the Marketplace who already do it perfectly and it's hard to compete with them. Nevertheless, we needed to have something to enrich the scene with. Michał spent a few weeks on vegetation and managed to make a few assets at an acceptable to us level.

Currently, our packs are available on the Unreal Engine Marketplace. We are still thinking about releasing the content on the Unity Asset Store but are not familiar with the market yet. And for now, we are having too much fun just creating new content.

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We also suppose that the new consoles and UE5 will have a huge impact on everyone's workflows. Perhaps, instead of creating manual retopos, it will be possible to rely on decimation algorithms. Or there would be no need to bake out lighting to make it look good.

Although in our opinion, the optimization process will remain similarly important and the real breakthrough will be in the scale of the maps and fidelity. There is still a lot of room for improvement when it comes to detailing and spreading assets around the levels.

We want to continue freely creating packs for the Marketplace as long as our business allows us. At the same time, we want to slowly turn our hand to interesting outsourcing graphics and VR projects, especially involving realism, photogrammetry, or lighting.

Thanks to all of you for reading.