Dear Sasview Team, I am using Sasview 4.2.2 to fit a colloidal crystal of polymer nanoparticles. Here I use a Form factor for spheres, where a polydispersity is included. Furthermore, I am using a hard sphere structure factor. I found the option to multiply the Spheres with hard spheres, so I can supply for each a radius and polydispersity. In this context I was wondering how the structure factor and form factor are combined (decoupling approximation, local monodisperse approx, ...) Thank you in advance for your help! Best wishes, Karina -- Karina Abitaev Institut für Physikalische Chemie Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany karina.abitaev@ipc.uni-stuttgart.de Phone: +49 (0)711/685-64502 Fax: +49 (0)711/685-64443