Using Linux at Lectra-Systèmes

Linux as used in CAD/CAM design by Lectra Systemes, France.
The Marker

The marker maker must optimise the material use, i.e., the piece of fabric called width, depending on the list of pieces given by the pattern maker. The quality of the work of a marker maker is expressed in the efficiency of a marker, which corresponds to the material quantity used in relation to the material loss. A good marker has an average efficiency of 85%, meaning 15% of the material is lost. A gain of a few tenths of a percent in production can have important economic consequences when it concerns costly materials like leather and high quality fabrics.

The Diamino software working on Linux/PC has a semiautomatic marker, making work easier for the marker maker as it facilitates positioning the piece. It also has a new automatic marking module (which marks all the pieces on the width without any manual intervention), the performance of which today is nearing 2% of that of a professional marker.

With the current PC architecture, it is now possible to obtain such a result at a very attractive price, whereas only a few years ago, the existence of an efficient module for the automatic marker was impossible due to material costs.

Figure 6 shows the evolution of the automatic marker making performances depending on the architecture used (time in seconds). The old Lectra X400 and X410 computers are based on the 68030 and 68040 processors operating under System V R4. The three PCs—DX2/66, Pentium75, Pentium120—used Linux kernel version 1.2.13.

Figure 6. Relative Performance of Automatic Marker Software on Various Platforms (time in seconds)

The Cut and Plot

The cut of the pieces can be done by hand or with a cutting machine, which has a better turnover advantage. In some cases, one does not cut the pieces, but just plots the shapes on a paper support to give to the sub-contractor.

The previous range of products from Lectra required the purchase of a computer per plotter or cutter, as the MILOS operating system of the computers was mono-task; in other words, the plotters and cutters were run by serial channel.

The new VigiPrint software developed under Linux controls about ten plotters simultaneously, giving a cost savings that should not be ignored when considering the configuration, together with much more facility in controlling the plot by managing the plotters on the same screen. The number of cutters managed by the software is limited to only one for safety reasons—the operator must be attentive to any blade break or other anomaly. The cut is made either with a blade (most common), a high pressure water jet (2000 bars), or a laser beam.

The Production Management

The Lectra suite of software, MasterLink and StyleBinder, enables managing all the data manipulated by the previous trades. In this way, it is possible for a given product to define the production follow-up folders which are filed in the relational databases. These databases make it possible to file various elements of a previous collection and re-use them in a current collection.

Below is a screen from the StyleBinder software under Linux.

Figure 7. StyleBuilder Software under Linux

Problems Encountered

The main problem is the integration of new peripherals, since the PC world is literally in the hands of Microsoft. Some peripheral manufacturers, mainly small manufacturers, are attentive to the Linux evolution and collaborate easily when designing drivers. The large companies are much more difficult to convince, and they often hide behind the imperatives of “marketing strategy”, refusing to supply the information required. Generally they refuse to accept any solution other than Microsoft, especially when it concerns technical support, since the development teams are rarely directly accessible in such structures.

However, the problems encountered are limited in number:

  • The MATROX Millennium board which was not supported by XFree86 because MATROX requires a non-disclosure agreement before they will release the technical information required. This situation is a hindrance for us, since the Lectra applications use specific peripherals, e.g., graphic tablets, miniature keyboards, ultrasound pens, which mean the X server must be altered to manage the “input extensions”. Our choice is therefore limited to boards based on S3 circuitry, like Diamond and #9.

  • Lots of storage peripherals connected via a parallel port can't be used with Linux, as each port is unique to each manufacturer and the information and protocol used are extremely difficult to obtain. Therefore, we use SCSI peripherals and internal drives on floppy port (ftape).

  • The Linux installation on the PC Notebook is sometimes difficult due to the special graphic circuits not supported by XFree86.

Other subjects have caused us, and in some cases are sometimes still causing us, a few worries:

  • The absence (at the moment) of a Microsoft Windows emulator at a professional level is a serious problem since our customers sometimes need to use documents from MS Windows to integrate them into our applications. The next software release of this type will be a boost for the generalisation of Linux as a desktop solution.

  • The swap management of Linux 1.2.13 does not seem quite as good as some other versions of Unix (such as SunOS-4.1.3). It appears the swap operating on Linux 2.0 has improved greatly.

  • The Lectra environment uses the SCSI interface intensively (for some top-of-the-line printers and scanners), and we have corrected a few bugs in the Linux SCSI driver. The corrections forwarded to the Linux developers seem to be integrated in the 2.0 kernel.