Should I ask for an STL or a STEP file?

What is an STL File? (The "Snapshot")

STL stands for Stereolithography. It is the most common format in the 3D printing world.

• How it works: An STL file represents the surface of an object as a mesh of triangles. It doesn't know about "holes" or "curves"—it just sees thousands of tiny flat triangles that approximate those shapes.

• The "Photograph" Analogy: Like a digital photo made of pixels, if you zoom in too far on a low-resolution STL, you will see the "facets" (the edges of the triangles).

• Best For: * Direct 3D printing.

  • Fast visual prototyping.

  • Hobbyist projects.

What is a STEP File? (The "Blueprint")

STEP (Standard for the Exchange of Product Model Data) is the gold standard for professional engineering and manufacturing.

• How it works: Instead of triangles, a STEP file uses mathematical equations to describe geometry. A circle isn't made of triangles; it is defined as a perfect mathematical arc.

• The "Vector" Analogy: Like a vector logo (SVG), you can scale a STEP file infinitely without losing any detail. It contains "solid" data, meaning the computer understands the volume, weight, and material properties.

• Best For:

  • CNC Machining and Injection Molding.

  • Reverse Engineering (modifying a part's design).

  • Professional CAD work (SolidWorks, Fusion 360, AutoCAD).

Which one do you need?

"Give me an STL if..."

You just want to 3D print the object exactly as it was scanned. If you have a broken bracket and you want us to scan it so you can print a replacement on your home printer, an STL is your best friend. It’s "plug and play" for almost every slicer software.

"Give me a STEP if..."

You need to change the design or manufacture the part using CNC machining. If we scan a vintage car part but you want to make the bolt holes 2mm wider, or if you need to send the file to a machine shop to be cut from a block of aluminum, you must have a STEP file.

The Blue Water Advantage: Bridging the Gap

At Blue Water Scanning, our Revopoint scanners naturally produce high-quality mesh data (STL). However, we specialize in the difficult work of Reverse Engineering—the process of manually converting that messy mesh into a clean, professional STEP file.

Not sure which one fits your budget? Contact us today, and we’ll help you determine if a simple scan (STL) or a full rebuild (STEP) is the right path for your project.