The French specialist in data transfer between CAD systems completes its offer with tools for reading files in SMG format. This is widely used for creating technical documentation from CAD files, especially in CATIA and SOLIDWORKS offers.

The French publisher Datakit, a specialist in tools for exchanging data between CAD systems, is adding tools for reading files in SMG format, which is widely used in the field of technical documentation, to its range.

The SMG (.smg) format was popularized at the end of the 2000s, thanks to 3DVia Composer from Dassault Systèmes, but it was born in 2002 in the French start-up Seemage, created by James Dugalais of the Claude Bernard University in Lyon and Eric Piccuezzu, who was technical director of several CAD editors (Apilog, Graitec, Robobat…).

A convenient format for viewing large assemblies
This start-up, based in Sophia Antipolis, developed Viz, a file visualization tool for which we did not have the author's license, Mockup to intuitively handle large CAD assemblies, then Seemage Presenter to present large projects. All were based on a proprietary file format using XML standards, which allowed it to recover most of the current formats of the time (CATIA; Pro/Engineer; Inventor; SOLIDWORKS; UG NX; Parasolid; JT, ACIS; STEP; IGES; VDA/FS…). The objective is to recover 3D digital models and combine them with other data to, for example, create technical documentation or educational content, thanks to the manipulation possibilities offered.

This format used tessellated patterns providing precision to 6 significant digits, but allowing compression up to 300 times, which made it easier to handle large files smoothly. Major manufacturers such as Alactel Alenia Space, Faurecia, Messier Dowty, PSA, Snecma, Thales… were among Seemage's customers to visualize projects reaching 50,000 pieces!

Popularization thanks to Dassault Systèmes
After starting a partnership with Seemage in the summer of 2007, Dassault Systèmes ended up acquiring Seemage in October 2007. Seemage's technology was then included in 3DVia Composer, then in CATIA Composer and SOLIDWORKS Composer, the technical documentation tools for leading Dassault Systèmes software.

"This format transforms a 3D CAD file into tessellated surfaces facilitating rendering," explains Frédéric Martinez, in charge of developing these tools at Datakit. "It is widely used by software from Dassault Systèmes, CATIA and SOLIDWORKS, to create 3D illustrations which will, for example, be used in technical manuals. This is even easier as the author of the original SMG file can add relative movements between the different parts of an assembly, to create exploded views showing, for example, disassembly operations for maintenance. »

In fact, Datakit's new tools retrieve in SMG format the various views of a 3D assembly created by the author, all the constituent parts in 3D, their realistic renderings and their relative positions (placement matrices), as well as the position of the camera. Then they generate a different file for each view in the desired format.

"The development of this library has not been the subject of major difficulties. Thanks to the experience we have, we have been able to understand the semantics and find out where and how the geometry is stored in this format, as well as the textures which are encapsulated in the file as JPEG or BMP images. »

For the moment, the geometry and the textures are recovered, other data, such as annotations and tables, will enrich the library as it is improved.

The libraries for developers, a converter for users
These reading tools in the SMG format, from version 3.6 to 7.8, have been available since April for software vendors in the CrossCad/Ware SDK, so that they can integrate Datakit's technology into their own application. These libraries provide a fully documented programming interface (API) to enable interoperability between CAD systems. The editors will thus be able to read and modify .smg files in their software (moving or deleting parts, changing colors or textures, etc.), because they have the entire tree structure of the assemblies available.

The users of CrossManager, Datakit's all-in-one conversion solution, can convert .smg files to a dozen other faceted formats (3DXML; 3MF; CGR; COLLADA; glTF; JT; OBJ; PDF 3D ; PRC; STEP; STL and VRML).

The advantage of these new tools is therefore to allow editors and users of software other than CATIA or SOLIDWORKS, to retrieve 3D views of assemblies in SMG format, in order to use them in their own software to create technical documentation or educational content. Note also the possibility of converting them to 3D PDF format, a widely distributed format that can be viewed by anyone without specific tools.