This paper presents a virtual lab for the contents of an Engineering project, for designing an agro-industrial building, which is also useful for a range of different transversal courses in Engineering sciences. The aims of this tool are to analyse the most important contents of a project-document (calculation, regulations, drawings and budgets), as well as their relationship with the activities which make up the work and the schedule. The design criteria we considered were: its online applications and their compatibility with Moodle; the inclusion of different learning approaches, such as exploratory learning and inquiry-based learning; its interactivity, and the use of multimedia elements for visualisation and direct analysis on material common to Engineering subjects. The students' perceptions of the improvements brought by the virtual lab were analysed statistically through a series of questions over two academic years. The results of the questionnaires suggested that most of those who had used the e-learning tool valued positively its overall suitability for reaching the objectives in their subject as well as the way it improved the working methodology. The practical knowledge acquired by the students was also highly valued. In addition, the lack of constraints commonly related to field trips (expenses, time and complexity) illustrates the utility of self-access learning tools in key transversal disciplines such as Engineering projects.