STL Viewer: 3D Print Files

STL Viewer opens 3D print files on your phone or tablet and shows them in clear, smooth 3D. It is an STL viewer made for makers: check a model's size, volume and filament before you print it, wherever you are and without internet.

Open models from the file picker, with "Open with" in your file manager, email or chat app, or from the share menu. Your files are read on your device and are never uploaded.

WHAT YOU GET
• STL (binary and ASCII), OBJ with MTL colors, 3MF and PLY files
• One finger rotates, two fingers pan, pinch zooms, double-tap resets the view
• Solid, wireframe and x-ray views, a print bed grid and XYZ axes
• Your choice of model color, or the colors saved in the file
• Model info: width × depth × height in mm or inches, triangles, volume, surface area, file size and a closed (watertight) mesh check
• Filament calculator: estimated weight and length for PLA, PETG, ABS or TPU, 1.75 or 2.85 mm, with an infill slider
• Recent files with previews (the 10 most recent without Premium)
• Six original sample models to try right away
• Large files load with progress and a Cancel button; very big models show a simplified preview, while model info and export use the full model
• Dark theme, a tablet layout with a side panel, and screen reader support

PREMIUM
• Measure: tap two points on the surface to get the distance and the X, Y and Z differences. Without Premium, you can watch a short ad to measure once.
• Section: cross-sections along X, Y or Z with a solid cut face, plus the section's width, height and area
• Scale & export: scale by percent or to a target size, convert inches to millimeters, and save as binary STL
• Compare: open a second model next to the first and compare dimensions, volume and triangles
• Unlimited recent files and no ads
Premium is a one-time purchase or a yearly subscription.

WHO IT IS FOR
• Makers and hobbyists: check a downloaded model before printing, see whether it fits your print bed and how much filament it needs.
• Students: open class projects anywhere, measure parts and look inside them with cross-sections.
• Sellers of 3D models: preview files before you send or list them, and confirm their dimensions and scale.
• Engineers and designers: review parts in a meeting or on the shop floor, check sizes and compare two versions.

QUESTIONS
Which files can I open?
STL (binary and ASCII), OBJ (select the MTL file too for colors), 3MF and PLY. For STEP, glTF and other formats, export the model as STL, OBJ or 3MF first.

Does the STL viewer work offline?
Yes. Viewing, model info and the filament estimate need no internet. A connection is used only for ads and purchases.

Which units are used?
STL, OBJ and PLY files store no unit, so millimeters are assumed; switch a file to inches if it was drawn in inches. 3MF files declare their unit. Sizes are shown in mm or inches, as you prefer.

Why is the filament amount an estimate?
It assumes a 0.8 mm solid shell (about two 0.4 mm lines) and your infill inside. Supports, brims and slicer settings change the real amount.

What does Premium add?
Measure, Section, Scale & export, Compare, unlimited recent files and no ads.

What about privacy?
No account and no sign-in. STL Viewer processes your models on your device and never uploads them.