Question 1

What is a 3D model file?

Accepted Answer

It saves the shape of an object, so you can turn it on screen and have it printed as something you can hold.

The letters after the dot in its name tell you the file type. For example, toy.stl is an STL file.

Question 2

What is an STL file?

Accepted Answer

A common file that saves a shape as tiny triangles fitted together. It doesn’t tell this viewer the color or measurement units.

Check the size after opening it. You can choose a print color later.

Question 3

What is a 3MF file?

Accepted Answer

Think of it as a little project folder. It can hold the shape, colors, size units, and printer settings together.

This viewer shows the saved colors it supports. Your maker can help match them to the colors available for printing.

Question 4

What are STEP files and CAD?

Accepted Answer

CAD is software for designing objects with exact measurements. STEP is a file type often used to share those designs, keeping their curves and shapes.

Names ending in .step or .stp mean the same file type. This viewer shows the shape in one color.

Question 5

What is an OBJ file?

Accepted Answer

Another file type for a 3D shape. Its colors or surface pictures may be saved in separate files.

Open the .obj file here to look at its shape.

Question 6

How is G-code different from a model?

Accepted Answer

A model describes what to make. G-code tells a particular printer how to make it: where to move, how fast, and how hot.

To order a print, send the original model so the maker can prepare instructions for their printer.

Question 7

Where can I find a model?

Accepted Answer

Model libraries such as Printables, MakerWorld, Thingiverse, and GrabCAD have designs to download. Look for an STL or 3MF file.

You can also make a design in a beginner-friendly CAD program such as Tinkercad, or ask a maker for design help.

Question 8

Why is my model gray?

Accepted Answer

Some files save only the shape. A 3MF can also look gray if it has no saved colors, or uses surface pictures this viewer can’t show.

Gray here doesn’t mean your print must be gray. Choose a color with your maker, or save colors in a 3MF project.

Question 9

How do I read the measurements?

Accepted Answer

Width: Side to side.

Depth: Front to back.

Height: Bottom to top.

“mm” means millimeters. There are 10 mm in a centimeter and 25.4 mm in an inch. Compare the numbers with a ruler.

Question 10

Why does my model look too small or too big?

Accepted Answer

Some files, especially STL, leave out whether their measurements are inches or millimeters. Mixing them up can change the size by about 25 times.

3MF and STEP can store measurement units. Check the numbers here, then tell your maker the size you want.

Question 11

How big can a print be?

Accepted Answer

It depends on the printer. Many home printers fit objects roughly 9–10 inches across.

A bigger object may need a larger printer, or be printed in pieces and joined. Your maker can check what fits and help choose an approach.

Question 12

How does a file become a real object?

Accepted Answer

1. Start with a model: The file describes the shape you want.

2. Prepare the layers: Software turns the shape into instructions for a printer.

3. Build it up: The printer adds one thin layer of material at a time, until the object is complete.

Your maker handles the setup and printing.

Question 13

How do I order a print?

Accepted Answer

Open your model and choose “Get this printed.” The same file goes to the quote page, where you choose the material and color.

A quote is a price estimate. Check the size and choices before placing your order.

Question 14

What is a slicer? Do I need one?

Accepted Answer

A slicer is software that plans the thin layers of a print. It works out the printer’s movements and settings.

Your maker does this for you. You don’t need to learn a slicer to order a print.

Question 15

Can one print have several colors?

Accepted Answer

Yes. A printer can switch between colors of plastic thread, called filament. Or a maker can print colored parts separately and join them.

A 3MF may save your color choices; an STL doesn’t. Tell your maker which colors you want.

Question 16

What are supports, infill, and layer height?

Accepted Answer

Supports: Temporary props under parts that would hang in midair. They are removed after printing.

Infill: The pattern inside a print, like honeycomb. It affects weight, material use, and strength.

Layer height: The thickness of each layer. Thinner layers can look smoother but take longer to print.

Your maker can help choose these settings.

Question 17

What do “watertight” and “manifold” mean?

Accepted Answer

They describe how a model’s surface joins up. Think of a closed shell: unwanted gaps or crossing surfaces can confuse the printing software.

A maker can check whether the shape needs repairs. This viewer lets you look at the model; it doesn’t check for those problems.

View your model.

Drop your 3D file here

3D printing basics