This licentiate thesis focuses on surface patterns, spatiality, and pattern relations in textile design, and aims to explore surface patterns as spatial definers and what they mean in the context of surface patterns. A secondary focus relates to applying conceptual spatial determinations as alternative design variables in design processes, and exploring how these could be used to define and analyse pattern relations. Through a series of exploratory design experiments that used printed and projected surface patterns in a three-dimensional setting, which were documented using photographs and film, the notion of pattern relations, wherein scale was used as a design variable, was explored. The outcome of the experiments showed the expressional possibilities that surface patterns may provide in a defined space, and how these are connected to pattern relations. In order to encourage an accompanying discussion regarding alternative methods of analysing surface patterns, the construction of a theoretical model was initiated. Workshops with design students were used as another practical method in this work. The results showed that there is great potential in using conceptual spatial determinations to define pattern relations by viewing surface patterns as spatial definers, rather than taking a traditional perspective on their functions. Another outcome is the theoretical model, which proposes a specific approach to pattern relations. This research demonstrates how conceptual spatial determinations can benefit the textile design process, as well as design teaching, which could in turn provide the field with new expressions that may lead to a change in or fruitful addition to the practice.