(a) Rapid-prototyping machines represent a large capital investment; consequently, few companies can justify the purchase of their own system. Thus, service companies that produce parts based on their customers' drawings have become common. Conduct an informal survey of such service companies, identify the classes of rapid-prototyping machines that they use, and determine the percentage use of each class. (5 marks) (d) How would you rapidly manufacture tooling for injection molding? Explain any difficulties that may be encountered. (7 marks) (c) Design a machine that uses rapid-prototyping technologies to produce ice sculptures. Describe its basic features, commenting on the effect of size and shape complexity on your design. (8 marks)