The SPLayOff command is similar to the LAYOFF command, except will turn off the "apparent" layer of certain Civil-3D entities.
Type SPLayOff at the command line, and select objects on the layers you wish to turn off.
Instead of selecting an item at the prompt, you may also key in the name of a Layer. You may use an asterisk (*) as a wildcard. For example, if you enter V-*-PH01 as a layer name, this command will turn off all layers with names that start with "V-" and end with "-PH01".
Unfortunately, at this time, the SPLayOff command does not work through XREFs. When selecting items inside an XREF, it will still turn off the overall layer, similar to the behavior of the default LAYOFF command. Also, the command currently only works on the following Civil-3D elements:
Primary Parcel Area Label
Parcel Segment Labels (not available in 2008 version)
General Line/Curve Labels (not available in 2008 version)
Parcel Segment Labels and General Line/Curve Labels (not available in 2008 version)
The way these labels are implemented in the API, each label may have two styles attached to it. One style is for Line Segments, and the other is for Curve Segments. Even though the label only displays one or the other, it always has both a Line and a Curve style attached to it. This can be seen by selecting the label and looking at its properties in the Properties Palette.
If both the Line style and the Curve style are set to display on the same layer, the SPLayOff command will turn off that layer. However, if the styles point two different layers, the SPLayOff command will ask you which layer you want to turn off, the one from the Line style, the one from the Curve style, or both. (Note that if you turn off both, and later use the UNDO command, you will have to use the UNDO command twice - once for the Curve style layer, and once for the Line style layer.)
Similar to the LAYFRZ command, except will freeze (or vpfreeze, in paperspace) the "apparent" layer of certain Civil-3D entities.
Similar to the LAYISO (Layer Isolate) command, except that when certain Civil-3D entities are selected, all layers involved in displaying the entity will remain visible. Also works to isolate entire XREFs, or individual layers inside of XREFs.
Similar to the LAYMCH (Layer Match) command, except objects are changed to match the "apparent" layer of certain Civil-3D entities.