Can a model change size when using a different filament type? I printed a case for my phone, a Motorola G4 Plus. I found the model of the casing on Thingiverse

I just downloaded the model, used Meshmixer to check for issues, after that, opened Simplify3d and saved it for printing using an SD Card. The printed size of the model was smaller than expected.

The model designer, says in the description that he used flexible filament. Is it possible than if I change to that filament, the model result is completely different?  

Print result - phone casing:
No, choosing a different filament type will not result in a different size (unless you use PLA that foams on extrusion, it increases size but then again all other dimensions would not fit either as it expands uniformly). The overall dimensions are defined by the coordinates in the G-code file which is based on the geometry of the model. If the printed model has dimensions that differ in the region of centimeters (like shown in your images) a different filament type will not change the size. Differences in the order of fractions of a millimeter are possible.

Probably the size has accidentally changed while loading the model in one of the tools prior to slicing to G-code.



Sidenote; there are techniques to anneal PLA after printing, you will then observe changes in the size of the part you printed, but I don't think you have annealed the print. From the link above:


  On average, you’ll see PLA shrinkage of about 5% and growth of about 2% along the relevant axes. If this shrinkage and growth is going to be a problem, you can compensate for it beforehand during the design and printing processes.