How do I check if my 3D print will be the right size?

Open your model in GeometryViewer and tap 'View in AR' on your phone. The model appears in your room at 1:1 real-world scale. You can see exactly how big it will be on your desk, shelf, or wherever you plan to put it.

Can I preview materials other than plastic?

Yes. GeometryViewer has 24 material presets in 6 groups: Plastics (smooth, rugged, rubber), 3D Print (PLA, PETG, Draft), Metals (chrome, steel, gold, copper), Aged (bronze, rust, verdigris, carbon fiber), Wood (pine, oak, walnut, cherry, maple, ebony), and Special (jade, glass).

Do I need to upload my file to a server?

No. Your file stays on your computer. All rendering and material simulation happens in your browser. Nothing is uploaded anywhere.

Preview Your 3D Print Before Printing

Q: Can I see what my 3D print will look like before printing?

Yes. GeometryViewer simulates layer lines for PLA, PETG, and Draft quality presets. Upload your STL file, select a 3D print material, and see realistic layer lines at 0.12mm, 0.20mm, or 0.35mm layer heights.

Q: What layer heights can I preview?

GeometryViewer has four 3D print presets: PLA Fine (0.12mm layers), PLA Standard (0.20mm layers), Draft (0.35mm layers), and PETG. Each shows realistic layer lines matching what your printer will produce.

Q: Does this work with 3MF files?

Yes. GeometryViewer supports both STL and 3MF files, the two most common 3D printing formats. 3MF is the newer format that supports multi-color and multi-material prints.

See exactly what your print will look like — layer lines, material finish, and real-world size — before you waste filament. Drop an STL above to try it.

Every 3D printer owner knows the pain: you slice, you print, you wait an hour — and the result doesn't look the way you expected. Wrong scale. Wrong finish. Layer lines more visible than you thought.

GeometryViewer lets you preview all of that before you print. Upload your STL or 3MF, pick a material preset, and see realistic layer lines at the exact layer height you plan to print. Then check the real-world size by placing it in AR on your phone.

Layer height comparison

See the difference before you commit. Each preset shows realistic layer lines matching what your printer produces.

PLA Fine

0.12 mm layers

Near-invisible lines. Best for display models, miniatures, and smooth surfaces. Slowest to print.

PLA Standard

0.20 mm layers

The default for most prints. Good balance of speed and quality. Visible lines up close, smooth from arm's length.

Draft

0.35 mm layers

Fastest printing. Very visible lines — good for prototypes and functional parts where looks don't matter.

24 material presets

Beyond 3D printing — see your model in chrome, gold, wood, jade, or carbon fiber.

PLA Plastic

With layer lines

PETG

Semi-glossy, layer lines

Chrome

Mirror reflective

Gold

Warm metallic

Copper

Warm reddish metal

Oak

Ring grain texture

Carbon Fiber

Woven pattern

Jade

Translucent stone

Plus 16 more: Steel, Bronze, Rust, Verdigris, Rubber, Pine, Walnut, Cherry, Maple, Ebony, Glass, Smooth, Rugged, Default, and two additional PLA presets. All available in the viewer toolbar above.

How to preview your 3D print

Three steps. Takes about 10 seconds.

Open your STL or 3MF file

Drag it onto the viewer above, or click "Open your STL or 3MF file." Both binary and ASCII STL are supported. No upload — your file stays on your device.

Pick a material preset

In the toolbar, open the material panel. Select "PLA Fine (0.12)", "PLA (0.20)", "Draft (0.35)", or "PETG" to see layer lines. Or try chrome, wood, carbon fiber — whatever finish you're curious about.

Check size in AR

On your phone, tap "View in AR." The model appears in your room at 1:1 scale. Put it on your desk. See if it fits on the shelf. Know the size before you print.

Who uses this

Real workflows where previewing saves time and filament.

Before hitting "Print"

Check if 0.20mm layer height is smooth enough, or if you need to drop to 0.12mm. See the difference before committing to a 6-hour print.

Showing clients

Print farm? Etsy seller? Share a GeometryViewer link with your customer. They see the model in 3D with the material you'll print in — and can check size in AR.

Choosing a finish

Post-processing? See your model in chrome, gold, or carbon fiber to decide what finishing to apply. The procedural textures simulate real materials.

Frequently asked questions

Can I see what my 3D print will look like before printing?

Yes. Upload your STL, select a 3D print material preset (PLA Fine, PLA Standard, Draft, or PETG), and see realistic layer lines at 0.12mm, 0.20mm, or 0.35mm layer heights. The simulation runs in real-time as you rotate the model.

How do I check if my print will be the right size?

Open your model and tap "View in AR" on your phone (iPhone or Android). The model appears in your room at 1:1 real-world scale. Walk around it, compare it to objects nearby, check if it fits where you want it.

What layer heights can I preview?

PLA Fine (0.12mm), PLA Standard (0.20mm), Draft (0.35mm), and PETG. Each shows realistic horizontal layer lines matching real printer output.

Does this work with 3MF files?

Yes. Both STL and 3MF are supported. 3MF is the newer format supported by PrusaSlicer, Cura, and Bambu Studio — it stores color, material, and build plate layout information that STL can't.

Do I need to install anything?

No. GeometryViewer runs in your browser. Works on Windows, Mac, Linux, Chromebook, iPhone, and Android. No plugin, no app, no account.

Are my files private?

Yes. Your file never leaves your computer. All rendering happens locally in your browser. No upload, no server processing, no tracking.

Stop guessing. Preview your print.

Drop an STL on the viewer above — or open one from ModelDirectory.

Open GeometryViewer

Need 3D models to test? ModelDirectory.org has thousands of free STL, OBJ, and 3MF files you can open here in one click.