Veranda
The Veranda plugin is a comprehensive patio roof configurator: a parametric 3D scene featuring posts, rafters, roofing, walls, and shading. You can set up features, rules, and prices as usual in the K3 Editor.
Because the plugin offers so many features, it has its own documentation section:
There you’ll find system requirements and licenses, instructions for integrating the plugin, basic terminology, a quick start guide, and descriptions of all models.