Viewer pages by format
What each format keeps when it opens
Formats differ most in three things: whether they know their units, whether they carry colour or textures, and whether a file holds one body or an assembly. That decides what you see after opening and what survives a conversion.
| Format | Units in the file | Colour and textures | Several parts |
|---|---|---|---|
| STL | none, read as mm | none | one mesh, parts detected by connectivity |
| STEP / IGES | declared unit, converted to mm | assembly colours kept | yes, mesh check per body |
| 3MF | stored in the model; we export it in mm | can be stored in the file | yes |
| OBJ (+ MTL) | none, read as mm | materials and textures (engine support, not tested) | yes |
| GLB / glTF | raw numbers as stored | materials and textures (engine support, not tested) | yes |
| FBX 7.x | unit scale not applied | textures (engine support, not tested) | yes |
| PLY | none, read as mm | not tested | one mesh |
| DAE (COLLADA) | unit honoured, shown in mm | textures (engine support, not tested) | yes |
CAD, print and scene files: three different jobs
CAD exchange files such as STEP and IGES hold exact surfaces. The viewer turns them into triangles with OpenCascade inside the tab, at Coarse, Medium or Fine precision; a rounded test cube becomes 48, 84 or 172 triangles. The first CAD file downloads that 7.6 MB engine once.
Print files such as STL and 3MF are already triangles, so they open fast and go straight to the mesh check, weight and cost.
Scene and asset files such as OBJ, GLB, FBX and PLY come from modelling tools, game engines and scanners. They often use metres or Y-up axes, which is why the converter offers a Y-up to Z-up rotation before a model goes to a slicer.
Smaller formats that also open
A few older or niche formats have no page of their own but open the same way: 3DS, WRL in VRML 2.0, AMF (plain or zipped), OFF and DAE. Each one opened in the test suite, most from files made by other tools. A zipped AMF came in with 3,682 triangles and a VRML 2.0 model with 4,532. A Maya COLLADA file in centimetres reads 800 × 1800 × 693 mm.
VRML 1.0, X3D and COLLADA files that store faces only as polygons do not open; the viewer shows a message instead of an empty screen.
From viewing to the next tool
Once a model is open, the header buttons work for every format. Convert writes STL, 3MF, OBJ, GLB, glTF, PLY, OFF or faceted STEP. Edit scales, repairs and cuts, and Slice turns the model into G-code. Plain STL files have their own page, the STL viewer, and the 3D model converter lists every pair that works.
Questions and answers
Which 3D model viewer formats are tested?
STL (binary and ASCII), OBJ, 3MF, GLB, glTF, Draco GLB, PLY, OFF, STEP, IGES, FBX 7.x, DAE, 3DS, WRL and AMF, each opened with the expected size and triangle count in the test suite.
Can I open a 3D model with textures?
Texture display for OBJ + MTL, glTF, FBX and DAE comes from the engine but has not been tested on our side yet. Geometry and size are tested.
Why is my GLB model 1000 times off?
GLB stores raw numbers and most glTF tools read them as metres. A 20 mm part exported as 20 units shows as 20 m elsewhere. Check the size in the Info panel and scale if needed.
Does the 3D viewer work without installing anything?
Yes, it runs in a Chromium browser tab. Firefox and Safari should work but have not been tested yet.