Abstract: A shadow moiré system (herein ‘system’) includes a glass grating that is disposed above a sample in an oven top and glass lid assembly of an oven such that the glass grating is vertically adjustable. Further, the system includes shadow moiré optics that is disposed above the glass grating. Furthermore, the system includes a vertical motion assembly that is disposed in an oven bottom assembly of the oven along with a sample support to vertically move the sample support and the sample disposed thereon. Additionally, the shadow moiré system includes a top heater assembly that is disposed in the oven top and glass lid assembly above the glass grating and a bottom heater that are separately controllable to generate and apply heat to the sample to observe any changes in flatness in a surface of the sample with temperature change.