3D models are digital representations of three-dimensional objects or environments that are created using specialized software. These models can be used for a variety of purposes, including animation, gaming, architecture, engineering, and product design.

There are several types of 3D models, including:

1. Wireframe models: These are the most basic type of 3D models, consisting of only lines and vertices that define the shape of an object.
2. Surface models: These models are created by adding a surface to a wireframe model, resulting in a more realistic representation of an object's shape.
3. Solid models: These models are created by adding depth and volume to a surface model, resulting in a fully three-dimensional representation of an object.

There are many software programs available for creating 3D models, including Blender, Autodesk Maya, and SketchUp. These programs use different techniques and workflows, but all aim to create a digital representation of an object or environment that can be viewed from different angles and perspectives.