The HDR and Full outputs of the Predict Engine render are stored inside an OpenExr image file (.exr). This format is specific to images that contains multiple layers (processed output, raw channels, normals, depth,...). The list of computed layers for an optical instrument depend on its definition and on the path tracer type.

Each layer computed by the optical instrument is saved in an OpenExr layer with the name <LayerName>.<ChannelName>. For instance: "S0.R" indicates the channel R of the layer S0 and "normal.X" indicate the x component of the normal vector. The channel name is omitted when the layer has only a single channel (material IDs, Depth,...).