This facet is motivated by the importance of licensing for distribution, redistribution, and modification of the tools, specifically for use in commercial applications. We found four different types of license, including open source, free without source in binary form, commercial, and commercial with free evaluation. The open-source tools can be provided under one of several wellknown licences, including the Eclipse Public License (EPL), the General Public License (GPL),the Apache License (ASL), the Berkeley Software Distribution (BSD) licence, or the MassachusettsInstitute of Technology (MIT) license. The main difference between these licences is in the redistribution terms, which can affect the use of the tools in commercial applications.

Comparison of Model Transformation Tools