The expanding design interest in outdoor comfort design is today supported by a few software tools. Given their different user-friendliness, modelling environments and simulation engines, a rational inquiry is how they are integrated into the digital design flow of architects and urban planners, which may include complex forms developments. Preliminary work is conducted to select architect-friendly tools that support the analysis of urban microclimate. A minimum set of criteria (amongst them the use of 3D models, the capability of calculating Mean Radiant Temperature and visual graphical outputs) led to the pre-selection of CitySim Pro, ENVI-met, Autodesk Thermal CFD, Grasshopper plug-ins Honeybee / Ladybug. The complex modelling experiment is conducted by simulating the outdoor thermal comfort of the space underneath the Rolex Learning Centre in Lausannewith each of the tools above. The paper describes and compares the principles, the procedures and the resources needed to prepare sound models that reduce the time of computation without compromising the quality of results. The potential applicability of tools in design is finally discussed from a user’s point of view. The tools’ capability of creating a 3D complex geometric model, or of importing one from a typical architectural tool, such as Rhino, is studied. Furthermore, it is debated how models can be used in the broader digital environment.