AbstractDigital design tools have dominated engineering and design practice offering many advantages that ultimately improve efficiency in the design process. Digital sketching is one such example of these tools yet, its current use is primarily to present work to stakeholders (External Communication). It is relatively underused to externalise ideas (Externalisation) where sketching on paper is still favoured. This paper aims to understand the characteristics of digital sketching that motivate or discourage designers to use the tool. Semi-structured interviews were undertaken with 12 designers to gain insights on the tool's use in External Communication and Externalisation. Results highlight a trade-off between fidelity of visualisations and time and effort expended to achieve visualisations. The key difference between the use scenarios is the way in which this trade-off is connected to managing stakeholder involvement. While designers acknowledge advantages that digital sketching can offer in externalisation, it is viewed as requiring a level of detail to begin use. In conclusion we suggest segmenting roles of digital sketching in terms of the characteristics identified in this study would help to motivate use in Externalisation.