The Complete JT to VRML Conversion Guide

Free-Form Surfaces Support:

JT: Full support | VRML: Partial support

VRML Notes:

Limited NURBS support in VRML 2.0

Impact:

Free-form surfaces allow a CAD user to design surfaces with advanced controls over curvature and continuitiy. While these surfaces are common for CAD models (in the form of so-called boundary representations or "B-reps"), they need to be converted to polygonal triangle or quad data to work with most 3D rendering engines - a process called tessellation. In this example, a surface patch is used to describe a part of a curved surface of a product. Without support for this feature, the free-form surface has to be tessellated into quads or triangles.

Geometry Compression Support:

JT: Full support | VRML: Partial support

VRML Notes:

VRML files can be compressed at the file level using gzip (.wrz extension). Geometry-level compression is not part of the VRML97 core standard, but prototype-based extensions exist — notably Taubin's GC node, a geometry compression scheme proposed specifically for VRML.

Impact:

Geometry compression describes the process of compressing the representations of a 3D model's geometry, usually a triangle mesh. 3D geometry compression does not change the topology of a 3D model, but just changes the way that a 3D model and its 3D positions and related vertex data is stored. Geometry compression can be lossy (just like JPEG compression in image processing can be lossy, for example), in which case one might notice slight artifacts like variations in 3D vertex positions (compared to the uncompressed 3D model). However, such differences are often not noticeable. There are only very few standards for geometry compression, like glTF's support of Draco compression and similar extensions.

Texture Compression Support:

JT: Partial support | VRML: No support

JT Notes:

JT stores texture images (typically as JPEG data) within binary segments, enabling compressed image storage. No GPU-level texture compression (e.g. BCn/DXT) is defined by the JT specification.

Impact:

Texture compression refers to a process of compressing 2D texture images for memory-efficient rendering (and sometimes for efficient transmission). The decompression of compressed texture data is therefore performed on-the-fly during rendering, so that it never has to be stored in unpacked form, but can be kept as-is in GPU memory. Formats supporting texture compression methods, such as the ones offered by glTF through KTX2 containers, therefore allow 3D models to use a smaller memory footprint on the client device during rendering. This can speed up rendering time, and also make it possible to store and use larger amounts of texture data than it would otherwise be possible.

Embedded Textures Support:

JT: Full support | VRML: No support

JT Notes:

JT fully supports embedding texture image data directly within the file as binary segments, making JT files self-contained.

Impact:

Embedded textures allow the storage and exchange of an entire 3D model and its materials within a single file, by embedding the texture images directly into the 3D file (and not storing them as separate image files). Without support for this feature, textures have to be stored in separate image files, and referenced from the main 3D model file.

Normal Mapping Support:

JT: Full support | VRML: No support

JT Notes:

Normal maps are fully supported in the JT material specification with no stated limitations.

Impact:

Normal maps are used to model shading differences that are arising from small geometric details on a surface, such as fabric structures, visible gaps between bricks forming a wall, or rough rock surfaces. In this example, a normal map is used to model a fabric structure. Without support for this feature, the rendered fabric will look smoother than it actually is in the real world, as the fabric structure won't be visible.