Entities as a Resources in SI General Discussions Posted March 25, 2020 You can just use a process with a WAIT step. On entity arrival you will fire and event and the process will go on. I also belive that a worker is derived from entity so you can use workers instead of entities. Or the best fitting thing is to use consume step to consume a material (the tools). And have two inventories for it (one near the machine, one in the warehouse of tools). There are some simbits with the basic inventory concepts.