What is a .wrl file?

What VRML was, and where it survives

VRML (Virtual Reality Modeling Language) was the 1990s attempt at 3D on the web, and as a web technology it is dead. Its successor X3D never took hold either, and glTF occupies that space now.

But .wrl files did not disappear, for one specific reason: colour 3D printing. For years, the standard way to send a full-colour model to a Zcorp, 3D Systems or Mimaki printer was a VRML file plus its texture images. Shapeways, i.materialise and Sculpteo all accepted VRML for colour prints, and CAD packages kept their exporters for that reason.

You will also meet VRML coming out of older FEA and visualisation tools, and out of SolidWorks and Creo, which both still export it.

What the file looks like

VRML is readable text with a scene graph of nodes:

#VRML V2.0 utf8

Shape {

appearance Appearance { material Material { diffuseColor 0.8 0.2 0.2 } } geometry IndexedFaceSet { solid TRUE coord Coordinate { point [ 0 0 0, 10 0 0, 0 10 0 ] } coordIndex [ 0, 1, 2, -1 ] }

}

Faces are lists of vertex indices terminated by -1, which allows any number of sides. Transform nodes nest to build a hierarchy.

The first line is a required header, and it is how this site identifies the format regardless of the file's name.

Units

The VRML specification states that the unit of measure is the metre. Like glTF, that is fixed by the standard rather than declared per file, so there is nothing in a .wrl to read. This site reads VRML as metres and says that it assumed the unit rather than reading it.

In practice, CAD exporters writing VRML for a printing service often write millimetre-magnitude numbers regardless. Check the overall size after conversion.

Colour

VRML stores colour per material and per vertex, and can reference external texture images. For a single-file upload the textures are not present, so a textured VRML arrives with its material colours but not its images.

VRML 1.0 versus VRML 2.0

Two incompatible languages share the extension. VRML 1.0 (1995) and VRML 2.0, also called VRML97, differ enough that a reader for one cannot parse the other. The header line distinguishes them. Nearly everything in circulation is 2.0.

What to convert it to

• 3MF if you are printing in colour on a modern machine. It carries colour

and units properly, and slicers prefer it

• GLB for viewing or sharing, which keeps colour and the hierarchy in one

file

• STL if you only need the shape and the destination is old
• STEP is not available from VRML, because there is no exact geometry to

recover. What you can do is reconstruct a faceted solid, with the limits stated on that page.