What defines flexible MDF in terms of structure and usage?

Flexible MDF is characterized by the incorporation of grooves or cuts within its structure that allow it to bend while maintaining some degree of strength. This unique property makes it ideal for creating curved shapes and components in design applications. The grooves reduce the material's thickness at certain points, facilitating the bending process without compromising the overall integrity of the board. This flexibility opens up a range of possibilities in product design, allowing for innovative forms and fittings that would be difficult to achieve with traditional rigid MDF.

The other options do not accurately define flexible MDF. The statement about it being entirely rigid and non-bendable contradicts the fundamental characteristic that defines flexible MDF. The assertion that it is primarily used in outdoor furniture is misleading, as flexible MDF is more commonly used in interior applications due to its susceptibility to moisture. Lastly, claiming it cannot be painted or finished overlooks the fact that flexible MDF can often be treated with various finishes, enhancing its aesthetic appeal and functionality in design projects.