You can change the linetype of a primitive object using the Properties Window. For more information, see AutoCAD Properties.
If a raster entity has a dashed line or other non-continuous linetype when you define it as a primitive object, AutoCAD Raster Design toolset changes the linetype to continuous if you edit the object, such as by stretching or smoothing it. You can then apply a linetype other than continuous to the object before merging it into the image.
For example, you want to extend a gas line, shown as a dashed line. You define the line as a REM primitive object and use grips to stretch the line to a new position. AutoCAD Raster Design toolset redraws this line as a continuous line. You use AutoCAD Properties dialog box to reapply the original linetype to the line before merging it into the image.