A new method has been developed for determining all three components of displacement at every point on a plane within a specimen deforming in an impact. By repeating the experiment, both the location of the plane and the time of the measurement can be varied, thus making it possible to visualise the entire 3-D flow throughout the experiment up to strains of many percent. The measurement technique involves 3-D digital speckle photography. The main experimental requirement is that the specimen is X-ray translucent, and can be fabricated with the measurement plane seeded with a random array of X-ray opaque particles, for example, lead filings. Experiments with epoxy resin and cement specimens being impacted by 9 mm ball bearings at ~375 m s-1 are presented. Stereographic pairs of X-ray plates exposed before and during the impact experiment are then compared by a computer program developed from a system designed for optical photographs. The spatial resolution of the current system is approximately 1 mm, with a displacement sensitivity of approximately 0.1 mm, though this could be improved by reducing the X-ray spot size