this castle model looks like it was made in Blender, the 3D design software. The details — such as the stone textures, moss, and lighting — are typical of what artists create in Blender using materials, shaders, and rendering engines like Cycles or Eevee.

In simple words: Blender is a tool where you can build shapes, add textures (like stone or wood), and then light the scene to make it look real. That’s how this castle was made