In Lect. Notes Math. 1181, 242-248 (1986; Zbl 0588.51015) the first author gave a construction for buildings of type M whose diagram contains no subdiagram of type \(A_ 3\), \(C_ 3\) or \(H_ 3\). The purpose of this paper is to extend the result to diagrams which may contain \(A_ 3\) or \(C_ 3\) subdiagrams but no \(H_ 3\) subdiagram. For doing this the authors introduce the concept of a blueprint. This is a set of data related to the several generalized n-gons which build up the building and contains information imposed by the diagram. For example in a diagram of type \(A_ 3\) the projective planes have to be Desarguesian. A blueprint is said to be realizable if there is a building carrying this blueprint. The first result of this paper says that a blueprint is realisable if its restriction to each rank 3 subdiagram is realisable. This result is used to show that there are buildings of any type. In fact the construction gives all buildings of spherical type, all buildings obtained from a BN- pair attached to Kac-Moody data (without using Lie-algebra) and many of the affine buildings.