| Extension | U3D |
| Full Name | Universal 3D |
| Type | 3D Model |
| Mime Type | model/u3d |
| Format | Binary |
U3D files are a 3D model format designed specifically for use in conjunction with PDF documents. The U3D format stores 3D model data in a manner that allows the file to then be embedded within a PDF document, enabling rich 3D content within a standard PDF.
Within a U3D file are the various data elements that make up the 3D model, including vertices, faces, normals, and texture coordinates. Along with this basic geometry, the face materials are also stored, which describe how the 3D object's surface should be rendered.
Support for exporting 3D content to the U3D format can be found in some 3D modeling software; in particular, the popular modeling software Daz Studio contains a U3D exporter.
U3D Converter Capabilities
Our U3D 3D Model/Mesh tool does not support any color material data contained within U3D files, so the converted file will not contain any color information.
The STL, or Standard Triangle Language, file format has been around since the '80s and is supported by most modern 3D modeling applications. In particular, the STL format has become something of a standard format within the area of 3D printing, despite the rise of more modern formats such as 3MF.
STL files come in two flavors: binary or text format. The text format is human-readable, making it easy to perform manual edits, but can lead to very large file sizes. As you can imagine, the binary format is much more compact and represents the majority of the STL files you are likely to encounter.
The format itself is very simple; the 3D model is represented by a sequential list of triangles, with each triangle defined with 3 points consisting of their X, Y, and Z positions, along with an additional vector that contains the face normal (the direction the face is pointing). There is an additional attribute block for each triangle; however, this is largely unused and thus unsupported.
STL Converter Capabilities
Our 3D conversion tool does not support color or material information in STL files, so your file will not contain any color information.
