In 3D model reconstruction from isometric drawing

it's a key step to reason the hidden elements. This paper proposes an algorithm to reason the hidden elements of the isometric drawing based on connected edges. Reason the hidden information is to reason through analysing these vertexes that have hidden edges

reason the direction and the length of connected edges and the edges that go through connected vertexes. After reasoning

we get some possible vertexes. Validating them with superposition and the edge circuits

we get the correct hidden element's coordinates and those circuits information.Then a method is introduced to seek the lost depth information based on the vertex's coordinates and those circuits information of the edges

its matrix is also brought forward. A prototype system To3D is developed using C and OpenGL tools to validate this method

the test result proves it's effective to reconstruct plan solid.