We introduce a new concept, reachable volumes, which denotes the set of points that the end effector of a chain or linkage can reach. This generalizes work on reachable distances for planar robots to 3-dimensional spherical joints. We show that the reachable volume of a chain is equivalent to the Minkowski sum of the reachable volumes of its links, which gives us an efficient method for computing reachable volumes. We present a method for generating configurations using reachable volumes for various types of robots including chain robots (with and without closure constraints), tree-like robots, and robots containing a combination of them. Unlike previous methods, ours works for 3-dimensional linkages with spherical joints and is capable of generating samples for problems with constraints on internal joints as well as end effectors. We show that reachable volumes samples are less likely to be invalid due to self-collisions, making reachable volumes sampling more efficient for higher dimensional problems. We also show that these samples are easier to connect than others, resulting in more connected roadmaps. Finally we demonstrate that our method can be applied to 262-dof, multi-loop, and tree-like linkages, problems where existing methods cannot be used (e.g., closed chains with spherical joints) or cannot be solved efficiently (e.g., tree-like robots and high degree of freedom chains with spherical joints).