Lighting source confirmation
  LED manufacturer/ Type of LED/ LED spec/ LED sample is required
  The LED position layout is needed
Optical requirements confirmation
  Required beam angle (in full view)/ if in half view, the light intensity curve is needed
  Other luminance demands, such as uniformity, certain level of lux in a specific area from a certain distance
Mechanical requirements confirmation
  The limitation of dimensions is necessary
Installed environment/ application/ other specific requirements, such as material.