You can route along a surface.
Click Rigid Route
in the Compass Toolbar.
The 3D Part / Product DS dialog box appears.
Enter details and click Finish.
The balloon appears.
Select Route Along Surface
> Surface
in the balloon.
Click on the surface you want to create the pipe.

Optional: Click Center
Offset Point
in the balloon to apply the offset from the center of the pipe
.
Note:
If you select the Bottom Offset Point
option then the distance is measured from the
XY plane to the bottom of the pipe.
Optional: Click Surface Distance
to set the offset distance.
The Distance From Surface dialog box appears.

Optional: Enter a value or use the arrows to change the value.
Continue clicking along the surface to route the pipe.
The pipe is created along the surface according to the offset settings.

Click Exit and Activate Parent
to validate and exit the command.
Note:
To route along a surface, you can also activate an existing pipe and use the Route Along Surface option.