Throughout the course of this book, we have examined many issues that affect the 3D printing of a model. We learned how to solve some of these issues by making adjustments with the slicer. However, many problems can occur by way of poor modeling. Modeling for 3D printing utilizes a different approach than what other applications such as 3D rendering and animation may require. A 3D model designed to be 3D printed must have a finished mesh that is triangulated and manifold.

What exactly is a manifold mesh? Simply put, it is a watertight form consisting of a contengous surface of polygons that completely forms a skin of the model. This is illustrated in the following image:

Even though there is a hole through the object, the mesh is manifold. It abides by the following four basic conditions: