Andy was given a line segment. He constructed a line segment bisector of the line segment using the paper folding method. He was told that the line segment bisector divided his line segment into pieces that are each 2.9 centimeters long. How long was Andy’s original line segment?

If the line segment bisector divided the original line segment into pieces that are each 2.9 centimeters long, then the length of the original line segment is twice the length of each piece. Thus, the length of the original line segment is $2 \times 2.9 = \boxed{5.8}$ centimeters.

To find the length of Andy's original line segment, we can use the fact that the line segment bisector divides it into pieces of equal length. Let's call the length of the original line segment "x".

According to the given information, each piece after dividing is 2.9 centimeters long. Since the line segment was divided into two equal parts by the bisector, each part has a length of 2.9 centimeters.

Therefore, the total length of the original line segment can be calculated by double the length of one part:
Total length = 2 * 2.9 centimeters

Simplifying the equation:
Total length = 5.8 centimeters

So, Andy's original line segment was 5.8 centimeters long.