There are many reasons for coating FDM parts. These include UV protection, sealing, shielding, or surface modification, but painting FDM parts for an aesthetically pleasing finish is the most common. Painting brings a product to life by adding depth, contrast and character. This is true for concept models, marketing samples, and finished goods. For product development and many production applications, paint completes the desired look and feel. With a little know-how and a touch of patience, models, prototypes, and parts can look like production parts. The following instructions are for creating top-quality painted parts. For applications that do not require this level of finishing, skip any unneeded steps. A good paint finish traditionally starts with sanding and filling.