In this guide I will show you how to use the free 3D modeling program FreeCad available from https://www.freecad.org/
FreeCAD is a free and Opensource 3d modeling program similure to Fusion360 and or other 3D modeling programs but others like OpenSCAD can also be used.
Denshi blocks are small transparent plastic locks that contain one or more electronic components used to build electronic circuits.
The blocks are still produced in Japan by DENSHI BLOCKMfg.Co.,Ltd see https://www.denshiblock.co.jp/
As shown in the image on the left, the oridginal Denshi blocks come in one or two primary sizes. The single block size is 17.5mm X 17.5mm X 17.5mm square with a 13mm X 6MM circular pip on the top and 2mm concave corners to locate between the baseplates pins while the double block is 35mm X 17.5mm X 17.5mm (double the length of a single) with an elongated pip on the top.
In order to allow voltage and current to flow, each single block and a thin sprun conductive plate in the middel of each mating surface while the double blocks have two contacts on each of the longer faces.
As I don't have the new kits, only the old legacy kits, this guide will focus on modeling the older style blocks.