Bent Pipes: Start the rate as usual (select the Rate tool and click once on a blank part of the sketch or on a level), then move the cursor to a place you want the pipe bent, hold down the shift key and click once on the sketch.  This drops a “corner”.  If you want more bends/corners, keep holding down the shift key and click on the sketch.  Finish the rate by clicking without holding the shift key down.
Split Pipes: Rate pipes can start or stop at three places: at a cloud on the sketch, at a level, and at a valve.  If, for example, you want a single rate to come out of one level and then to split and feed into two levels, this is how you do it.  Create the three levels.  Join two together with a rate.  Again with the Rate tool, click on the valve of the first rate, then hold the shift key and click on a blank part of the sketch near the third level, then click on the third level.  (This makes Vensim put the rate pipe on the sketch and bend it near the third level.  If you don’t do this, you might find that Vensim draws the pipe with its bend through the second level, because pipes can only be horizontal or vertical.)
You can also make the illusion of a pipe splitting off somewhere other than a valve (see page 22 of the Vensim Modeling Guide) by clicking on the valve, then creating a bend on top of the existing pipe, then making another bend near the level and finishing on the level.  The two pipes will be drawn exactly on top of each other, creating the illusion of a single pipe at that point.

Posted in: Diagramming