1906
However , like the 2D cases presented above , reducing support structures is based on the compromise of adding more volume in the structure itself , which will decrease the global optimality .
 concept or principle: 2D; engineering feature: support structures; concept or principle: volume; concept or principle: structure
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; engineering feature: support structures; concept or principle: volume; concept or principle: structure