Yard control features

A method of manufacturing a plurality of optical elements, the method comprising:

• providing a substrate;
• providing a tool comprising, on a replication side, a plurality of replication sections, each replication section defining a surface structure of one of the optical elements, the tool further comprising at least one contact spacer portion, the contact spacer portion protruding, on the replication side, further than an outermost feature of the replication sections;
• aligning the tool and the substrate with respect to each other and bringing the tool and a first side of the substrate together, with replication material between the tool and the substrate, the contact spacer portion contacting the first side of the substrate, and thereby causing the spacer portion to adhere to the first side of the substrate;
• hardening the replication material;
• and
• separating the tool from the substrate with the hardened replication material adhering to the substrate, wherein the substrate has yard line features around at least a portion of the replication sections, the yard line features configured to contain the replication material on a first side of the yard line with respect to the substrate.