1908
`For these investigations discussed above , the 2D TO process is relatively easy to realize when only considering overhang or support structure AM constraint .
 concept or principle: 2D; concept or principle: process; process parameter: overhang; engineering feature: support structure; manufacturing process: AM
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: manufacturing standard, machanical property, manufacturing process, material, engineering feature, process parameter, machine or equipment, application, process characterization, enabling technology, biomedical, concept or principle 
Text: {0} 
Answer:
 concept or principle: 2D; concept or principle: process; process parameter: overhang; engineering feature: support structure; manufacturing process: AM