You know you really don't know how to explain stuff!
![:lol:](http://192.241.182.11/images/smilies/lol.png)
An origin brush is a brush textured with the origin texture and tied togther with a rotating solid entity! The origin brush is the place that the object will rotate around it so it doesn't have to in the center!
![;)](http://192.241.182.11/images/smilies/wink.png)
The only entity that doesn't rotate but still needs an origin is func_train!
![:D](http://192.241.182.11/images/smilies/grin.png)