Creo

A PRT file is a part file created by PTC Creo Parametric, a CAD program part of the Creo suite that is used to design manufactured parts and assembly processes. It contains part information, including a 3D model and part structure. PRT files can be combined with other parts into an assembly file (.ASM file).

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STL

STL (STereoLithography) is a file format native to the stereolithography CAD software. This file format is supported by many other software packages; it is widely used for rapid prototyping, 3D printing and computer-aided manufacturing. STL files describe only the surface geometry of a three-dimensional object without any representation of color, texture or other common CAD model attributes. The STL format specifies both ASCII and binary representations. Binary files are more common, since they are more compact.

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