1982
This requirement is critically important for parts with complex geometries which include curved surfaces , thin connecting features , hidden features and lattice structures .
 concept or principle: complex geometries; concept or principle: curved surfaces; engineering feature: lattice structures
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: complex geometries; concept or principle: curved surfaces; engineering feature: lattice structures