🖨️ Hold your math and science in your hands
Download a model you just turned in 3D and print it on a school, library or home 3D printer. Every file is free, made by code as a clean solid, and checked before it is offered.
⚠️ An adult runs the printer. The nozzle (about 200 °C) and the bed are hot. Keep the room aired. Never leave a print running alone. Under 13: only with an adult right there. Resin printers are for adults only.
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How every file was checked
- Closed (watertight) surface, every edge shared by exactly two triangles, triangles facing the same way, and no triangles crossing each other.
- A flat base, and every piece of a set rests on the bed.
- Walls at least 1.2 mm thick across 99% of the surface. Sharp corners are rounded so there are no thin points.
- Sizes in millimeters; every model fits a 180 × 180 × 180 mm printer bed. Files that fail a check are not offered.
How we estimate grams and time: PLA weighs 1.24 g per cubic centimeter. We count about 1 mm of solid skin plus the infill shown. Time: an average school printer lays about 4 mm³ of plastic each second, plus 5 minutes to heat up and about 2 seconds per layer; supports add about 15–20%. Your slicer gives the exact numbers for your printer.
STL files store no units: open them as millimeters. 3MF files keep the units. All models are Goal100's own designs, free for class and family use; please keep the credit line “Goal100 Learning” when you share a printed model.