About: http://webisa.webdatacommons.org/260877679

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	yea, need is a strong word you mean like, projecting obstacles into local-coords of the object simulated ? i have read that is a common way; makes the math easier.
http://www.w3.org/ns/prov#wasQuotedFrom	java-gaming.org