Terms such as 3D printing, rapid prototpying, and layer-based manufacturing all refer to essentially the same process: the laying down of material in layers to create a 3D form.

Different techniques, and the materials that can be used with each have distinct advantages and disadvantages. 

Rapid prototyping processes typically follow a 3-step workflow.

1. First, a model is created in CAD software. This model contains information about the physical form, shape, and dimensions of the object.

2. The 3D model is then processed by Slicing software. This software takes the model and slices it into layers - much like a sandwich.  Each layer represent a particular cross-section of the object. Parameters such layer thickness, wall thickness, and infill can be set in the software. Learn more about these parameters here.

3. The sliced file is then sent to the rapid prototyping device for manufacture. In most cases, this will involve the device cutting or depositing material in the pattern set by the slicer software. Layer upon layer is added until the form is complete. 

LOM is similar to PRP, in that it uses thin layers of polymer which are cut and layered together. This process is used to create scale and presentation models which can be used to gather user/client feedback on form. 

In this process an object is created by selectively curing a thin layer of liquid resin with a laser. A laser heats selected areas of the resin, turning it into a solid. The process continues until the piece is completed.

The most accessible type of 3D printing technology, FDM involves the laying down of thin layers of material, usually a type of plastic. The  filament is heated in a nozzle and then "drawn" on layer by layer.