Multicoat, surfacer-less effect and/or color paint system producible by first applying a primer coating composition to a substrate and optionally curing it, applying a first pigmented basecoat coating composition to the primer obtained in stage, optionally applying a second pigmented basecoat coating composition to the first basecoat film, obtained in stage, applying a transparent coating material composition based on at least one polyhydroxyl group-containing compound and at least one polyisocyanate group-containing component to the first basecoat film, obtained in stage, or - if a second basecoat coating composition has been applied - to the second basecoat film, obtained in stage, and jointly curing the first basecoat film, the second basecoat film, where present, and the transparent coating film, characterized in that the transparent coating material composition comprises (i) at least one rheological assistant based on fumed silica and (ii) at least one polyisocyanate group-containing component which additionally has at least one structural unit of the formula -NR-(X-SiR"x(OR')3-x), and/or with at least one structural unit of the formula -N(X-SiR''x(OR')3-x)n(X'-SiR''y(OR')3-y)m, where R = hydrogen, alkyl, cycloalkyl, aryl or aralkyl, it being possible for the carbon chain to be interrupted by nonadjacent oxygen, sulfur or NRa groups, where Ra = alkyl, cycloalkyl, aryl or aralkyl, R' = hydrogen, alkyl or cycloalkyl, it being possible for the carbon chain to be interrupted by nonadjacent oxygen, sulfur or NRa groups, X,X' = linear and/or branched alkylene or cycloalkylene radical having 1 to 20 carbon atoms, R'' = alkyl, cycloalkyl, aryl or aralkyl, it being possible for the carbon chain to be interrupted by nonadjacent oxygen, sulfur or NRa groups, n = 0 to 2, m = 0 to 2, m+n = 2, and x, y = 0 to 2. first applying a primer coating composition to a substrate and optionally curing it, applying a first pigmented basecoat coating composition to the primer obtained in stage, optionally applying a second pigmented basecoat coating composition to the first basecoat film, obtained in stage, applying a transparent coating material composition based on at least one polyhydroxyl group-containing compound and at least one polyisocyanate group-containing component to the first basecoat film, obtained in stage, or - if a second basecoat coating composition has been applied - to the second basecoat film, obtained in stage, and jointly curing the first basecoat film, the second basecoat film, where present, and the transparent coating film, (i) at least one rheological assistant based on fumed silica and (ii) at least one polyisocyanate group-containing component which additionally has at least one structural unit of the formula -NR-(X-SiR"x(OR')3-x), and/or with at least one structural unit of the formula -N(X-SiR''x(OR')3-x)n(X'-SiR''y(OR')3-y)m, where R = hydrogen, alkyl, cycloalkyl, aryl or aralkyl, it being possible for the carbon chain to be interrupted by nonadjacent oxygen, sulfur or NRa groups, where Ra = alkyl, cycloalkyl, aryl or aralkyl, R' = hydrogen, alkyl or cycloalkyl, it being possible for the carbon chain to be interrupted by nonadjacent oxygen, sulfur or NRa groups, X,X' = linear and/or branched alkylene or cycloalkylene radical having 1 to 20 carbon atoms, R'' = alkyl, cycloalkyl, aryl or aralkyl, it being possible for the carbon chain to be interrupted by nonadjacent oxygen, sulfur or NRa groups, n = 0 to 2, m = 0 to 2, m+n = 2, and x, y = 0 to 2. R = hydrogen, alkyl, cycloalkyl, aryl or aralkyl, it being possible for the carbon chain to be interrupted by nonadjacent oxygen, sulfur or NRa groups, where Ra = alkyl, cycloalkyl, aryl or aralkyl, R' = hydrogen, alkyl or cycloalkyl, it being possible for the carbon chain to be interrupted by nonadjacent oxygen, sulfur or NRa groups, X,X' = linear and/or branched alkylene or cycloalkylene radical having 1 to 20 carbon atoms, R'' = alkyl, cycloalkyl, aryl or aralkyl, it being possible for the carbon chain to be interrupted by nonadjacent oxygen, sulfur or NRa groups, n = 0 to 2, m = 0 to 2, m+n = 2, and x, y = 0 to 2.