LDM files are files created by VolumeViz Large Data Management (LDM). LDM is a program that is used to visualize complex volume data sets. LDM files contain visualization data, which may add up to up to hundreds of gigabytes (GBs) in size. LDM files are used to store large data sets and render them for real-time display and three dimensional image generation. LDM files are used when the entire set of visualization data cannot be loaded into active memory, such as in scientific visualization.