Generating a 3D file 

Generating a digital model is the initial step in the 3D printing process. The most common method for generating a digital model is CAD drawing. Then comes the other way to get a 3D model is by reverse engineering via 3D Scanning. Also, you can download the predesigned 3D designs files from the internet.
There are several design considerations that must be evaluated when designing for 3D printing i.e. feature geometry limitations, support material and escape hole requirements.

Creating STL, obj etc. 

For 3D printing, a CAD model must be converted into a format that a slicing software can interpret and later a 3D printer is able to interpret. This starts by converting the CAD model into a STereoLithography (STL) file, also referred to as Standard Triangle Language or Standard Tessellation Language. There are also other file types .AMF and .OBJ or 3DP but are less common.
STL uses polygons to define the surface of an object, to simplify the complex CAD model. Almost all the CAD software is capable of exporting a model as an STL file.
Once an STL file has been generated, the STL file is imported into a slicing software, which slices the model into layers that will be later used to build up a part. The slicing software converts the STL file into a GCode file. GCode is a numerical control programing language used in CAM to control automated machines like 3D printers.

One touch print with VAFER

Combine vafer's smart features to create elegant, cohesive parts with just selecting the Gcode file that you have sliced.