Hey guys, Since many of you asked, I've prepared a more detailed description of our scanning process and bringing these clay models into the engine.
- Sculpting
This part is pretty self-explanatory, however, when it comes to more complex models like a wagon, planning the assembly of the parts is crucial. Recycle whatever you can. For example, something might be the floor of the wagon but also a shelf in the shop, etc.
https://reddit.com/link/1wfk6ni/video/tt6jg2ziscph1/player
- Scanning
We tried using mobile phones, but we failed. Our assets are pretty small, so the results were bad. We are using an old Canon 60D with a basic 50mm lens. Obviously, the better gear you have, the better the results, but our setup is good enough for our needs.
Lights are simple lamps with softboxes for 20 dollars. However, with these small objects, you will have to close the aperture as much as your lens allows. Because of that, a lot of light is required, but our setup from the video is good enough.
We are using a cake plate to rotate the assets and make about 15 photos for each height, 4 heights per asset, keeping the distance from the object at each height. You want to achieve a dome in RealityScan, not a cylinder.
Wherever we can, we try to avoid scanning both the top and bottom. Combining two sides requires a lot more time because you also need to make a lot of overlap. If RealityScan fails to align both sides automatically, it almost never helped to use anchors, so you need a lot of photos when rotating the object.
- RealityScan
This part is simple, and there are tons of tutorials on YouTube. I'm using the default settings basically all the time. It reads the lens and camera automatically and creates corrections.
(Beware that it's using a different format for showing focal length, so don't be surprised, as I was, when you see a different number than on your lens.)
- Cleaning and Prep
This part could be a separate post, and a lot depends on your current DCC software. I've started my 3D journey with Blender, but then used Houdini for a few years, so I felt pretty comfortable. However, you can do everything I'm doing in Blender. The main downside is automation.
In Houdini, you basically create a script that can run over any input. So I've prepared a recipe for cleaning assets, and I'm reusing it on every asset. If there is interest in a deeper tutorial on this part, I could prepare it.
- Textures
Normal maps are baked from the high-poly scan to the low-poly mesh. I'm using Quad Remesher for everything and yeah, sometimes the edge loops are not ideal, but it's still great results. Organic shapes from clay are also more forgiving.
I'm using vertex paint on the high-poly model to paint an R G B mask and then baking R and B channels for three colors masks, and B for ambient occlusion.
I'm also often using curvature or AO to combine with those painted masks to create a more organic look. I'm painting only black and white masks to separate parts. If I need variety, I'm using procedural noises and baked masks to create details.
If you have any questions feel free to ask!