The BBC documentary 'The Greatest Tomb on Earth: Secrets of Ancient China' claims that Qin sculptors weren't capable of creating the terracotta army or the more recently excavated acrobat sculptures, and argues that Greek experts were likely present to teach the local craftsmen the necessary techniques.

Are these claims as conclusive and irrefutable as the documentary suggests? And can anyone comment on how difficult it would really have been for Chinese sculptors of the time to create these works without outside help? As a lay person in both history and sculpture, the idea that lifelike sculptures would be impossible to create just because prior to that time the dominant form of sculpture in the region were small and heavily stylized figures seems absurd.