Planning Heavy-Duty Robot Chassis Materials

Hi friends, I like robots and learning how to make strong and stable frames for bigger projects. I want my robot carry some weight without falling or bending. I see many people here share metal frames and 3D printed parts very interesting! In my work I sometimes do structural steel takeoff services, so I think about how much material is needed before building. Maybe same idea can help to plan robot chassis like how many metal beams, screws, and plates for strong frame. Does someone here have tips to choose best metal or method to calculate materials for robot frame? I want strong but not too heavy. Any advice or example projects are very welcome. Thanks and happy making!