1911
As is the case with the 2D variants , these 3D TO practices mainly focus on how to minimize overhang area or support volumes , as these constraints are relatively easy to integrate in the TO process .
 material: As; concept or principle: 2D; concept or principle: 3D; process parameter: overhang area; application: support; material: as; concept or principle: process
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:
 material: As; concept or principle: 2D; concept or principle: 3D; process parameter: overhang area; application: support; material: as; concept or principle: process