In clay modeling, a creator makes a model by using the shapes of objects, including hands. In contrast, in traditional 3D modeling environments, shapes are assigned by the systems a priori, i.e., no real world object's shape is used. In this paper, we present Scan Modeling, in which the creator performs 3D modeling by scanning any real object. To realize Scan Modeling, we developed an input device called "Wakucon". Wakucon is square-shaped with 245 millimeters per side. The creator uses it to scan a cross section of a shape by placing it inside of the device. By moving the Wakucon or the objects inserted into the device spatially while scanning these objects, the creator can perform 3D modeling. In this paper, we show interaction techniques and implementation of Scan Modeling. Additionally, we present an evaluation of the accuracy of reconstructed 3D models when using the Wakucon.