Rendering Vs Scale model
Renderings are useful for review, but they have limitations. Most of the people (your clients) have a hard time understanding Architectural drawings and a rendering is one step in the right direction. However, scale models are real-to-touch miniature bulidings that your clients can understand and relate to. Scale models can also help save costs by helping you find mistakes, before the building is actually build.

What are the key advantages of Scale models
Most importantly, scale models are accurate, although some features like mullions are sometimes thickened to be visible at small scale. You can recreate topography to visualize how the building fits in its surroundings. You can often choose colors (depending on the rapid protyping process used), but it may add to the cost. The scale models can be created fairly quickly (1-4 weeks depending on complexity).

How to minimize cost?
Rapid Prototyping machines are still costly today and so is the material used by these machines. These two factors primarily contribute to the cost of scale models. You can typically minimize cost by:
     - Minimizing machine (print) time by reducing height/ scale of the model
     - Minimize material cost by reducing the volume of the model

Can you work with paper drawings or 2D AutoCAD drawings?
Yes. The service providers are able to use your 2D drawings and re-create a 3D model (STL file), required for creating a scale model.