Paulina Kucharska is designing a 3D medieval fantasy environment in Unity to accompany her previous 2D game called Unicorn Slayer. She begins by creating a basic terrain map and importing medieval asset packs. Paulina works on sculpting the terrain using painting and texturing tools to add mountains, grasslands, and a body of water. She populates the landscape with trees, buildings, and other props. Throughout the process, Paulina refines the terrain, adds more details like paths and fences, and decorates locations like a town and mansion to complete her virtual world.