This paper developed themes concerned with designing tools to assist young users to create 3D models published in a book chapter in 2001 with Bailey, F. Children's Creation of Shared 3D Worlds in Digital Content Creation, eds. J Vince & RA Earnshaw, London, Springer, 1852333790. The research used the particular case of children authoring virtual environments, amongst other sources, to uniquely develop an argument for distinguishing between the novice and amateur user in designing software. This is an extension of Moar's interests in children as users of digital technologies into the broader context of interface design. The paper addresses two key research questions: - What may we learn about interface design from children's use of professional tools? - What are the differences between novice and amateur users? Based on the observational data from the VERTEX project (described previously), together with a detailed analysis of the relevant literature, the case that amateurs and novices represent two distinct classes of users is proposed. It is also argued that identifying this distinction may assist in designing interfaces. The analysis also underlines the usefulness of the techniques of foregrounding and backgrounding of features in interface design. The ACM Creativity and Cognition conference is internationally refereed. The distinction between novice and amateur users is being explored further as part of the AV Cube project undertaken by Moar and Parry within the Lansdown Centre at Middlesex University, looking at how professional composers and inexperienced children create 3D sound compositions.