Neutral files and neutral file interfaces are needed in order to exchange product data between CAD systems. Also direct translators exist but the the number of needed translators is becoming large if there are many CAD systems involved in the data transfer. For each pair of CAD systems to be communicated two translators are required, one for each direction. Figure 7 shows the situation using direct translators. Using a neutral file format only one pre- and post-processor is needed for each CAD system. Figure 8 shows the situation of the data transfer using a neutral file format. Descriptions of some of the most common neutral file formats follow.
Figure 7: Situation with direct data transfer
Figure 8: Situation using a neutral file