Making a prototype using rapid prototyping technologies requires CAD software. This software allows you to design a part on a computer, controlling its shape and dimensions and making design adjustments based on the chosen manufacturing technique.
However, whether you are able to develop a feasible CAD design probably depends on your level of design and engineering experience.
Those without prior CAD experience may need to consult a professional product designer to fulfill the design brief. Professionals know how to manipulate the CAD software, and they also know whether a design can realistically be fabricated using hardware like a CNC machine. (We often receive designs that are not manufacturable because they do not take into account factors like draft angles, parting lines and overhangs.)
Those who do have CAD experience — product designers, R&D specialists, etc. — can create a digital design using their design suite of choice then export it to a machine-readable format such as a STEP file (for CNC machining, etc.) or a Mesh file (for 3D printing etc.).
The CAD file is the most important step, but you must also specify a desired material, quantity and surface finish (if required) to the prototyping company.
In many cases, you may prefer to send off Requests for Quotation (RFQs) to several prototyping companies in order to compare quotations in terms of price, proposed lead time and the reputation of the manufacturer.
Once a satisfactory quotation has been received, you can finalize the order with the prototyping company, who will use your digital design and order specifications to commence production.
The prototype will be shipped to you once production is complete.