Fast STL Viewer

Fast STL Viewer

Contains adsIn-app purchases

About this app

Professional STL inspection and measurement on Android. Wall thickness analysis, printability checks, point-to-point distance, volume, surface area, cross-sections — tools that used to require a desktop workstation, now in your pocket.

Trusted by engineers, dental technicians, medical device teams, jewellery designers, and quality control inspectors worldwide. Over 1 million downloads.

PRO INSPECTION TOOLS

▸ Wall Thickness Heatmap
Spot thin walls and weak points before they become print failures. Color-coded heatmap (red → yellow → green) maps thickness across your entire model. First mobile STL viewer with wall thickness analysis.

▸ Printability Dashboard
Four automated mesh checks: open edges, flipped normals, non-manifold geometry, degenerate triangles. Interactive 3D overlay highlights each issue directly on your model. Catch defects before they waste material and machine time.

▸ Normal Visualization
Per-face normal vectors with adjustable length, color, and thickness. Verify surface orientation at a glance — essential for diagnosing reversed faces and print artifacts.

▸ Cross-Section Slicing
Adjustable X, Y, Z cutting planes to inspect internal geometry. See what's inside without splitting the file.

MEASUREMENT TOOLS
- Point-to-point distance — tap two points, get the dimension
- Volume and surface area with unit selector (mm, cm, in)
- Bounding box dimensions (X, Y, Z)
- Properties panel: triangle count, dimensions, full geometry stats

VISUALIZATION
- 5 rendering modes: shaded, wireframe, combined, point cloud, normals
- 6 standard views: top, bottom, left, right, front, back
- Orthographic projection for accurate dimensional inspection
- Custom mesh, scene, wireframe, and point cloud colors
- Adjustable lighting — matte to glossy material appearance
- Automatic detection of unconnected components within a single file — instantly color-coded for assembly review
- Open boundary detection — identify non-watertight geometry before printing

WORKFLOW
- Load multiple STL files for side-by-side comparison
- Open from Gmail, Google Drive, WhatsApp, or any file manager
- Share STL files directly from any app
- Select and open multiple files at once via the in-app file picker
- Save and export

BUILT FOR PERFORMANCE
OpenGL ES 3.2 and native C++ with hardware-accelerated mesh analysis. Handles files with millions of triangles. Binary and ASCII STL.

USED BY PROFESSIONALS IN
◆ Engineering & QC — Verify wall thickness on brackets, housings, and structural components. Inspect cross-sections. Measure dimensions before manufacturing. On-device inspection for incoming parts.
◆ 3D Printing — Run printability checks before every print. Open edges, flipped normals, thin walls — catch them before they cause failures.
◆ Dental — Inspect crowns, bridges, and aligners. Measure dimensions, verify wall thickness on thin anatomical geometry.
◆ Medical Devices — Review implant and prosthetic STL files. Cross-section through anatomy, verify specs.
◆ Jewellery — Wall thickness on filigree and prong settings. Mesh integrity before casting.

Try any Pro feature free — watch a short video to unlock for 1 hour. Upgrade to Pro to keep them all.

Ratings and reviews

the recent ads, even worse now, uninstalling and finding a better one. edit for developer: I doubt many people use the file > open to access a stl file. If we download a batch of stls we close then the app is auto selected via the phone when we open stl #2, that's one ad per file opened. furthermore, I had used this app for years while making ornaments (4+ years) it was NEVER this bad and it had always been free. something changed and it's going to cause the app score to take a dive.

Viewer is great, but doesn't associate file types in the phone's OS. Any time I click on a file to open, it sends me back to the google play store. Instead, I have to open the app and navigate to the file location. This is particularly annoying as a rural user because I'm often out of coverage and the play store won't load. Makes comparing multiple files a significant PITA.

Overall it served it's purpose, initially. M Then I became more savvy in the art and needed something more than a tool that views and an editor that went more in depth if having to pay. Thank you but unfortunately it's time to move up to another app. Without this app I would have never peaked my interest in this field. A field I now can comfortably say will be my future in all aspects of the term

What’s new

New: Overhang analysis — pick a build direction and threshold to highlight areas that will need supports.