Registered forum members do not see this ad.
... when using Inventor PIPE RUN ...
When you are using PIPE RUN, once you have selected the origin of your pipe (to begin your "route"), and the projected line appears, if that line is not long enough for where you want the pipe to go before the next bend -
use SHIFT then the PLUS (+) key to extend the projected line.
(However, my personal preference is to use the ENTER DISTANCE option.)