Preparing Models for 3D Printing

Downloaded a model from STLRepo? Here's how to prepare it for a successful print.

What You Need

3D Printer: Any FDM (filament) printer will work. Make sure you know your print bed size (common sizes are 220x220mm, 235x235mm, or 300x300mm).

Slicing Software: Free options like Cura, PrusaSlicer, or Bambu Studio. This software converts your 3D model file into instructions your printer can understand. The slicing software you use might be more convenient to use specific to your 3D printer.

Filament: PLA is recommended for beginners. Make sure you have enough filament for your print (your slicer will tell you how much you need measured in g, kg, or in some cases by length)

The Model File: Download the STL, 3MF, or OBJ file from the source platform linked on STLRepo. Most files you download will be in STL format if downloading from a site like Thingiverse.

Step 1: Check the Model

On the Source Platform: Before downloading, visit the model page on Thingiverse, Printables, or MyMiniFactory (linked from STLRepo) to read the description, check print photos from other users, and review comments for any known issues or tips specific to that model. You can avoid many headaches by learning from how others successfully printed the model. Learn more about the best sites for 3D models to understand different platforms.

After Downloading: Open the file in your slicer to preview it. Look for obvious problems like missing parts, weird geometry, or whether the model is the right size. Most slicers will show warnings if there are issues with the file which it may be able to repair for you.

Step 2: Scale and Position

Check the Size: Make sure the model fits on your print bed. Your slicer will show if it is too large. Scale it down if needed, or split large models into multiple parts if your printer dimensions don't allow the full size to be printed.

Orient for Success: Rotate the model to minimize overhangs (anything angled more than 45 degrees will likely need supports). The flat side should usually face the print bed. How you orient the model affects both print quality and how much support material you will need. Some slicers like Bambu Studio have an option that can determine the best orientation for the model loaded.

Step 3: Add Supports (If Needed)

When to Use Supports: If your model has overhangs, bridges, or parts floating in the air, you will need supports. Most slicers can add these automatically or you may choose to add them manually.

Support Settings: Start with 10 to 15 percent support density. Tree supports are easier to remove than grid supports and leave fewer marks on the model. Check the original model page as creators sometimes specify if supports are needed and where to place them.

Step 4: Configure Your Slicer

Essential Settings:

• Layer Height: 0.2mm is a good starting point for most prints
• Infill: 15 to 20 percent for decorative models, 30 to 50 percent for functional parts
• Print Speed: Use your slicer's default speeds when starting out
• Temperature: Follow the recommendations on your filament spool

Bed Adhesion: Add a brim (a few extra outline layers) for tall or small models that might tip over. A raft (a platform under the print) helps if your first layer is not sticking well.

Print Time: Check the estimated print time in your slicer. Some models can take several hours or even days to complete.

Step 5: Final Checks

Before you hit print, make sure your print bed is level and clean, your filament is loaded and ready, and you have enough material for the entire print. Your slicer will estimate how long the print will take and how much filament it will use.

For complex or large models, consider printing a small test version first to verify everything works before committing to a full size print.

Common File Issues

Model Will Not Slice: If your slicer shows errors or refuses to process the file, try using the built in repair tool (most slicers have one). You can also try downloading the file again from the source platform in case it was corrupted. For more troubleshooting help, see our troubleshooting guide.

Wrong Scale: Some models are designed in inches but your slicer expects millimeters (or vice versa). If a model looks way too big or too small, try scaling it by 25.4x or dividing by 25.4 to convert between units.

Material Quick Guide

PLA: Easiest to print, good for beginners, works on most printers without a heated bed. Best for decorative items.

PETG: Stronger than PLA, slightly harder to print, needs a heated bed. Good for functional parts that need durability.

ABS: Strong and heat resistant, but requires a heated bed and enclosed printer. Fumes can be unpleasant.

TPU (Flexible): Rubber like material that requires slow printing speeds and specific settings. Not recommended for beginners as more experimenting is required for this material.

Quick Tips

Visit the original model page through STLRepo to find printing recommendations from the creator and see what settings other users had success with. Many creators include specific temperature, speed, or support notes that can save you time and failed prints.

Start with default slicer settings and adjust only one thing at a time if you encounter problems. Keep notes on what works for your specific printer and filament combination.

Most importantly, your first print of a new model might not be perfect. That is normal. Small adjustments to orientation, supports, or temperature usually solve most issues.