The lost foam process is extremely similar to the investment casting process sometimes leading to confusion between the two. Lost foam is essentially the same process as investment casting except that that patterns are created using expanding polystyrene foam instead of wax. There are also some differences in the shell building process due to this change. Many of the benefits of investment casting can also be attributed to lost foam; however, tooling and processing costs make the process more prohibitive with little to no additional benefit. As such, investment casting is the much more popular choice for production.