Building a batting cage measuring 12x12x70 feet requires careful consideration of structural integrity, particularly regarding the load-bearing capacity of the proposed 4 steel posts. The posts, suggested to be 4 x .120 A500/A513, must adequately support the net, which weighs approximately 140 lbs. It's essential to assess local batting cages for insights on post configurations and load management. The design should account for wind, rain, and snow loads, as well as potential debris impact during storms. The span of 70 feet may necessitate additional support, such as guy lines or triangular bracing, to prevent sagging. Exploring existing structures and available kits for design inspiration can provide valuable guidance in ensuring the batting cage's stability and durability.