We built a bi-directional scatter diagnostics to measure and quantify losses due to scattering and absorption of harmonic conversion crystals (DKDP) for the National Ignition Facility (NIF). The main issues to be addressed are (1) amount of total energy reaching the target if the target hole was +/-200 prad in size, (2) distribution of energy inside the target hole, (3) collateral damage of other optics by scattered light. The scatter diagnostics enables angle-resolved measurements at 351 nm, and is capable of both near specular transmission and large angle scatter measurements. In the near specular setup, the transmission can be measured within +/-65 pad up to +/-60 mrad acceptance angle. A silicon photo detector and a scientific grade CCD camera provide total energy and energy distribution. A linear swing arm detection system enables large angle scatter measurements of 360 degrees, in principal, with step sizes as small as 0.01 degree and different collection angle ranging between 1 and 20 mad. In this paper, scatter effects from laser damage and final finishing process of DKDP are discussed.