Although the integration of PV systems in the building envelope (BIPV) is an important factor for the acceptability of such installations, current urban-scale solar potential metrics only partially consider this aspect. As part of the definition of BIPV-suitable surfaces, we argue that a geometric-regularity criterion can help predict the possible disposition of solar panels already in the early assessment of BIPV potential in urban contexts. To address this need, we developed an algorithm for the geometric sampling of the parts of the building envelope achieving a minimum irradiation threshold, with the aim of defining uniformly-covered active solar surfaces. The proposed methodology is implemented in a flexible parametric design platform and tested in a case study in Neuchâtel (Switzerland). We show that integrating geometric regularity in the assessment of BIPV potential can have a significant influence in the calculation of the solar energy production and discuss the value of such information in urban planning practices.