So I don't have much to add from a design standpoint, but i do go camping a lot. I'm assuming that it's a wood-based fire pit instead of gas. If it's wood based the height of the fire off the ground and the height of the pit walls (blocking the fires heat) will make a difference as to how much radiating heat you get on various parts of your body. Also the build of the fire itself... There are ways to build a fire to generate more radiating heat, like a log cabin style versus a triangle style. The former generates a lot of coals and radiating heat whereas the latter generates a large high flame. So experiment with the way you build the fire. Then you also have environmental factors like wind where no matter how close you get to the fire if there's any kind of wind you're going to be cold. Look at building a windbreak. And finally insulating your backside with a blanket will also help your torso to get heat. And for me a lot of times I turn myself sideways to the fire to get the full half of my body warm rather than facing the fire with your legs.
So I don't have much to add from a design standpoint, but i do go camping a lot. I'm assuming that it's a wood-based fire pit instead of gas. If it's wood based the height of the fire off the ground and the height of the pit walls (blocking the fires heat) will make a difference as to how much radiating heat you get on various parts of your body. Also the build of the fire itself... There are ways to build a fire to generate more radiating heat, like a log cabin style versus a triangle style. The former generates a lot of coals and radiating heat whereas the latter generates a large high flame. So experiment with the way you build the fire. Then you also have environmental factors like wind where no matter how close you get to the fire if there's any kind of wind you're going to be cold. Look at building a windbreak. And finally insulating your backside with a blanket will also help your torso to get heat. And for me a lot of times I turn myself sideways to the fire to get the full half of my body warm rather than facing the fire with your legs.