Tools > Disk Decimate (applicable when no polygon object exists in the Model Manager) systematically thins the polygons from a disk file that is too large to open, thus preparing it to be opened by the application.
After you specify the name of a disk file to decimate, enter a value for one of the following. (Defaults are taken from Tools > Options > General > File I/O > Large Data. Maybe.)
Target Triangle Count (initial value is the current number of triangles) - specifies the target number of triangles in the decimated model.
Reduce to Percentage (0 to 100) - specifies a percentage of points to be eliminated by decimation.
OK button - saves the decimated object to the Model Manager.
Cancel button - closes the dialog without saving an object to the Model Manager.
Apply button -