A method, a computer medium storing computer instructions performing a method, and a computer with processor and memory perform stress modeling as follows. The stress model transforms a representation of a material conversion of a first material in the integrated circuit to a second material in the integrated circuit. Prior to the material conversion the first material occupies a first space having a first boundary. After the material conversion the first material and the second material together occupy a second space having a second boundary. The first space and the second space are different. The stress model performed by the computer system transforms the representation of the material conversion of the first material to the second material into: i) the first material occupying the first space having the first boundary, and ii) a strain displacement condition of the first material. The strain displacement condition is determined by a spatial change from the first boundary to the second boundary.