Tips for buying 3D Prints and Designs

Understanding 3D Printing

The most common technique to print is fused deposition modeling (FDM),and leaves visible layer lines on the object's surface unless additional post-processing is done. It works by depositing a liquid material that solidifies, one layer at a time.

Printing thin objects of less than a few millimeters or highly detailed surfaces is difficult with this technique. Sellers offering high-detail figures might use another printing approach such as resin printing.

3D Printing Materials

• PLA/PLA+: Indoor use only, easy to print. (most common)
• PETG: Rigid, water-resistant, if exposed to the sun, it will turn yellow.
• TPU: Flexible, good for prints that will flex.
• ASA: Ideal for outdoor uses, rigid, and difficult to print.

Food Safety Considerations

3D printed objects are not food-safe by default due to the small grooves left by layer lines, which can trap bacteria. Proper post-processing is required to make prints safe for food contact.

• PETG is FDA-approved as food-safe but still needs post-processing to be truly hygienic.
• ASA is another food-safe material that withstands water, UV, and heat, making it suitable for outdoor use as well as food and drink applications—if properly treated.

Sellers may sand, paint, or chemically smooth 3D prints to improve their look and feel. These extra steps enhance the final product but typically increase the price due to the added labor and materials involved.

If you want to know more about 3D Printing Materials check our detailed guide.

3D File Types and Their Functions

• STL: The most common format for 3D printing. It represents objects as a mesh of triangles but does not store color or texture information. Since it approximates curved surfaces using polygons, fine details may be lost. If printing in multiple colors, you’ll need to assign them manually in the slicer.
• STEP: Becoming the preferred format for high-precision models that don’t involve complex organic shapes like characters or animals. Unlike STL, STEP files store true curved surfaces instead of approximating them with polygons. When imported into a slicer, the object is converted into a mesh, and you can choose the level of precision. Higher detail settings may slow down slicing and require a more powerful computer.
• OBJ: Supports geometry, textures, and colors. More accurate than STL since it can store curved surfaces and polygons, but not as precise as STEP files. Commonly used for rendering and multi-color prints.
• 3MF: A more advanced format that retains metadata, colors, and multiple material assignments. Unlike STEP, it represents geometry as a mesh (similar to STL and OBJ). It’s useful for previewing how a print will look but lacks the precision of STEP files.

Before purchasing or downloading a model, check the file format to ensure it suits your needs, whether for single-color, multi-material, or highly detailed prints.

Important Factors to Consider

1. Printer Compatibility: Ensure your 3D printer supports the file format.
2. Resolution & Detail: Higher detail requires better printers.
3. Licensing & Usage Rights: Some designs restrict commercial use.