Is it a model pattern or drafting? Model patterns are for surfaces, drafting for cut patterns. Surface patterns are a real world size, ie a brick pattern regardless of scale will be real size so on a very small scale they would be a solid blob so revit turns them off or to a solid grey tone. Drafting patterns are a set print size, ie a cross hatch set to 1/16th in spacing will print lines that when measured on paper are allways 1/16th regardless of scale.