Is there a way to change the color of the preview of a solid made in Dynamo in the Revit interface?
I don’t think so, maybe @jacob.small knows if this is possible or not
There is a material called something like “Dynamo” created for this when you launch Dynamo for Revit, which can allow you to edit the traffic cone orange to other colors as desired. This is a “all one color” setting, but does allow for variation of colors if your design makes the orange too hard to see.
I do not believe that line color can be modified.