The Complete IFC to PLY Conversion Guide

Free-Form Surfaces Support:

IFC: Full support | PLY: No support

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:

IFC: Partial support | PLY: No support

IFC Notes:

IFC-ZIP provides compression for large models

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.

Materials Support:

IFC: Full support | PLY: Partial support

Impact:

Materials are a fundamental concept in 3D modeling, enabling colored and - in many cases - photorealistic rendering of the 3D model that they are applied to. There are also some formats that don't make use of 3D materials, for example because they need to solely describe a shape (e.g., for many cases in additive manufacturing). In this example, photorealistic PBR materials are used to equip the 3D model with a realistic look. Without support for materials, the model will have to be rendered with a default material (often a default shade of gray).

Transparent Materials Support:

IFC: Partial support | PLY: No support

IFC Notes:

Transparency supported through material properties

Impact:

Transparency is commonly used for see-through objects, containing (usually partially) transparent surfaces. In this example, a transparent material is used to model the glass window of the microwave, so that one can see inside. Without support for this feature, the inside of the microwave cannot be seen, as the window will be rendered as an opaque surface.

Scene Nodes Support:

IFC: Full support | PLY: No support

Impact:

Scene nodes make it possible to address parts of a 3D model separately. For example, a part could be dynamically hidden or shown as part of a 3D configurator. Without support for this feature, a 3D scene will only consist of a flat model, without parts being individually configurable.

Hierarchical Scene Graph Support:

IFC: Full support | PLY: No support

Impact:

Scene graphs are one of the most common concepts in 3D computer graphics. By structuring the scene in a hierarchical way, logical parts of it can be easily addressed and transformed. This is useful in many applications, like games or 3D configurators. Without support for this feature, a 3D scene cannot be structured hierarchically, for example objects cannot be logically composed of smaller objects.

Scene Composition Support:

IFC: Full support | PLY: No support

Impact:

Scene Composition describes the process of composing a scene through links from a main scene that pull in various other scenes/3D models. This can also happen in a nested fashion (through multiple levels of linkage). With a target format not supporting this feature, references to external models must be resolved and the content be baked into one 3D model, which is then saved in that target format.

Standardized Format Support:

IFC: Full support | PLY: No support

PLY Notes:

Compatibility of all properties strongly depend on particular compatibility of the tools that export / import the DCC file, as there is no clear standard for this format.

Impact:

Standardization plays a huge role in 3D model formats. With a format being standardized, every application will have a clear way of how to load or store data using this format. This makes it easier to re-use the 3D model across different applications, but also to make sure it will still be accessible and usable after a couple of years.