Currently, only the cargo's mass is used in the game, which is fine when dealing with hyperspace jump distances. But when it comes to transporting stuff in a cramped container, volume (e.g. cubic meters) is also very important (see car when going on vacation).
When you take for example gold, a cubic meter weighs approximately 19 tons or a ton is just some 52 liters. When you transport 4 tons of gold with your puny sidewinder you are just using only 5% of the volume of your cargo bay (assuming it has a volume of 4 cubic meters). I think being able to continue to add more cargo until you fill up the volume would add some good complexity (*) to the game.
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* complexity:
Let's just define complexity very simply as "doing something". It doesn't matter how stupid "doing something" is, only how much of it you're doing. So, bad complexity is when you're doing more whithout getting anything out of it, e.g. like docking at a station to find out that there are no appropriate missions on the bulletin board (why couldn't i read the missions from outside the station; i can still dock if i have to transport some cargo). Then, good complexity is when i do more, but also get something in return. So, when i spend more time to find the perfect cargo load, i get a higher profit in return.
When you take for example gold, a cubic meter weighs approximately 19 tons or a ton is just some 52 liters. When you transport 4 tons of gold with your puny sidewinder you are just using only 5% of the volume of your cargo bay (assuming it has a volume of 4 cubic meters). I think being able to continue to add more cargo until you fill up the volume would add some good complexity (*) to the game.
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* complexity:
Let's just define complexity very simply as "doing something". It doesn't matter how stupid "doing something" is, only how much of it you're doing. So, bad complexity is when you're doing more whithout getting anything out of it, e.g. like docking at a station to find out that there are no appropriate missions on the bulletin board (why couldn't i read the missions from outside the station; i can still dock if i have to transport some cargo). Then, good complexity is when i do more, but also get something in return. So, when i spend more time to find the perfect cargo load, i get a higher profit in return.