Question

fff: types of infill
use the information below to answer the question about types of infill.
in the fuse filament fabrication (fff) process, infill is the structure inside of an object that holds it together. infill is a series of repeating shapes that come together and make a structure to support the inside of an object. this makes the object stronger than if it was hollow, or completely filled with the filament.
how is infill used for 3d models?
used for exterior surface tension
used as a guideline for 3d models
used for interior structural support

Explanation:

The text states that in FFF 3D printing, infill is the internal repeating structure that holds the object together and provides support for the inside, making it stronger than a hollow or fully filled object. This directly aligns with the purpose of interior structural support.

Answer:

used for interior structural support