Technology used in 3D printers has been rapidly evolving in recent years. Today, there are even 3D printers capable of representing complex internal structures of three-dimensional objects, printing in full color, or using different materials in combination.
Conventional 3D printing data formats come with several limitations—for example, they lack the ability to describe an object's internal structure or to retain information on the colors or materials used to print objects. These existing formats also involve many steps, including troublesome intermediate processing for data conversion as well as the work required to recover data that was corrupted during processing.
To address these issues,FUJIFILM Business Innovation, in collaboration with the Keio Research Institute at Shonan-Fujisawa Campus (SFC), has researched and created FAV, a new voxel-based*2 data format. FAV*3 enables users to freely model and control complicated internal structures and attributes, thus expanding the range of expression that is possible through 3D printers. The FAV format also makes it possible to eliminate troublesome data conversion processing during the flow of 3D data, enabling a workflow that is consistent from start (input/creation of 3D data) to finish (printing).
The specifications of the FAV format are now being released here as an open format. In response to demands from customers who were involved in our initiative for practical applications of FAV, we have updated the specifications of the FAV format. In 2019, version 1.1a of the specifications of the FAV format was published as a Japanese Industrial Standard (JIS).*4
The FAV format expresses 3D data in the form of voxels (the three-dimensional equivalent of pixels) arranged three-dimensionally (Fig. 1). For each voxel, users can define various attribute values including color information (RGB, transparency, etc.), material information (ABS, nylon, etc.), and physical properties (harder, softer, etc.). Users can also control the relationships (e.g., connection strength) between different voxels. This data format allows users to create three-dimensional objects with a higher degree of freedom. For example, in addition to freely designing the distribution of multiple materials, it is possible to design the internal structure of an object made of a single material or to finely configure the settings of manufacturing equipment (Fig. 2).
Fig. 2: The FAV format is able to retain information on internal structure, color information, and material information.
The FAV data format also allows voxel data to be used as-is for different kinds of simulations. Users are then able to easily modify the design of a three-dimensional object based on the results of these simulations. For example, after performing a structural analysis, such as a simulation of object deformation due to external forces, users can redesign areas that had high amounts of distortion, making changes in the materials used or adding structural modifications (Fig. 3).
It is also possible to use the attributes that are defined for each voxel, including the connection strength between neighboring voxels, for applications such as making design changes to achieve a desired strength or optimizing the toolpath or fill density for 3D printing.
The update to version 1.1a has widened the range of applications of the FAV format. In the updated version, users can divide a single voxel into subunits and define various attribute values for each subunit. This enables users to change the level of detail of an object represented in the format depending on their purposes. For example, users can choose to obtain a general view of the whole object or to focus on a specific part of the object that requires special care and perform a thorough analysis of this part.
Moreover, users can now register their desired information as attributes that can be specified for each voxel. Various kinds of desired information, such as the pressure applied to an object while it is being used, water solubility, and the settings of the manufacturing machine used for manufacturing the object, can be managed in the FAV format and utilized in design and fabrication processes (Fig. 4).
- *1 The first 3D data format in the world to be able to retain not only information on the surface of a 3D model but also information on internal structures, colors, materials, and connection strength.
- *2 Voxel: A basic element of 3D data. Voxels are used to express three-dimensional objects in the same way as pixels are used to express two-dimensional images.
- *3 FAV (abbreviation for "fabricatable voxel"): a new voxel-based data format proposed by FUJIFILM Business Innovation and Keio University in collaboration.
- *4 JIS B9442: Specification of FAV format for 3D models
- * This research is also a product of the Japanese Ministry of Education, Culture, Sports, Science and Technology's COI (Center of Innovation) project "Center of Kansei-oriented Digital Fabrication," for which Keio University serves as a central base. The aim of this project is to achieve a society in which anyone can easily manufacture items using 3D printers.