Ok. I have two filters DOMESTIC COLD WATER and OTHER COLOR PIPE.
What the DOMESTIC COLD WATER filter does it looks for pipes that belong to the system classification Domestic Cold Water.
In my view I used this filter in the visibility/graphics overrides (on the filter tab). When Pipes are falling in this category I make them green (with the settings in under projection/surface).
What the OTHER COLOR PIPE filter does it looks for pipes, pipe acessories, pipe fittings and pipe insulations that have the parameter PIPECOLOUR set to RED. IT only looks for the text RED. If the parameter PIPE COLOUR does not have the text RED (e.g APPLE) the filter does not apply.
If you look at the pipes you will notice that ALL the pipes belong to the system classification Domestic Cold Water. Some pipes have a the PIPE COLOUR set to RED. Others have a adifferent value. You could ask why are not all the pipes green, they all belong to the Domestic Cold Water system classification? The filter DOMESTIC COLD WATER for them is true. Still some of the pipes are not Green...why?. This is because some pipes are also true for OTHER COLOR PIPE (the parameter PIPE COLOUR is RED). The reason they become red is because the OTHER COLOR PIPE filter is above (higher) than the DOMESTIC COLD WATER filter. This OTHER COLOR PIPE filter has higher precedence and thus applies
So at the moment the only important entry for PIPE COLOUR is RED. Because that is what we are filtering on. If I change the filter to look for PEAR and change the parameter PIPE COLOUR for some of the pipes also to PEAR it still would work and the pipes will become red.
So to see pipes in other colours you would have to duplicate the filter OTHER COLOUR PIPE (and give them distinctive names) several times. For each duplicate filter you have to decide om what word it is going to filter. You add the filter to the view and set the line and patterns to colours you like (i.e. Brown, Green, Blue & Yellow).
The colours indeed do dissapear in realistic view. This is because in Realistic Revit show not the colours but the material. This will get bit more complicated. I will see if I have time tomorrow to help you with that.
Louis
Please mention Revit version, especially when uploading Revit files.