What do you mean by "selecting all the pieces of the TIE fighter?" Surely you are not trying to use multiple models at once? You must have just one model of a full TIE. And remember the func_train must contain a piece of origin brush (just a brush totally covered with system/origin texture). The way I prefer is to make a small piece of nodraw or caulk and a small piece of origin inside that, turn those into a func_train. Then use the model2 key to bring in the model in game. Using model2 key you won't see the model in Radiant, only the pieces of brush. However, in game the situation is reversed: You see only the model, not the invisible origin nor the mandatory piece of other brush the entity must contain.
You use path_corners just by targeting a path_corner to the next path corner on the path you want to build. Target the func_train to the first path_corner of the path. Otherwise, read and study the entity properties.
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Frozen by ICARUS
Frozen in the past by ICARUS