What is the correct direction to draw a pipe? Alignment vs. Flow

[Anonymous]

When creating a pipe network, should the start point of each pipe drawn represent the high, or upstream side of the pipe, as to draw the pipe network in the direction of flow?

Or, adversly should the start point of the pipe drawn reference the direction and stationing of the alignment?

I have a profile which has an alignment which direction and stationing contradict the flow direction of the pipe, and the structure invert labels are correct, but on the wrong side of the structure. ie. the Upstream side of the MH is to the North and the downstream side is to the South, yet the invert located on the upstream side of the invert label line is the Southern invert. and vice versa. I believe this is because the structure invert label style labels the end of pipe invert first (on the left side), then the start of pipe invert (on the right side)

Which is the correct way to draw the pipe network?

I'm using Civil 3D 2011, and 2013, but this drawing is in Civil 3D 2011.

Cheers

[Joe-Bouza]

I could be wrong but I think the link upstream downstream toggle on the tool bas is so yu can pick your poison

[mathewkol]

I've found it to be most successful to draw up to down. I've found some weirdness when drawing down to up, even with that toggle and even being able to change direction of flow.

[MikeEvansUK]

Agreed. I always draw downhill to avoid confusion mostly it's easy to get it wrong only to find a pipe is back falling but displays a correct gradient.

Also vb applications use the start point & endpoint to change gradients etc. this will cause a pipe to be incorrect.

Note also the swap pipe function just swaps the flow direction and not the actual pipe it's self.

[Joe-Bouza]

makes sense ... follow gravity

[wfberry]

Make Sense?

It depends on which side of the bed you got up on.  Coming from a construction background we always lay out and construct from the low end to the high end.

Obviously we have to design from the top down since flow seems to increase as we go down the terrain. <G>

Bill

[Anonymous]

Thank you for the input,

So moving forward, I will build my pipe network in the direction of flow, and to avoid the structure label high side/low side reversing issue, I'll station my alignments in the direction of flow as well. In the odd case where I have to deal with an opposing alignment stationing vs. flow direction, I'll have to manually input the structure invert elevations so that they appear on the correct side of the structure in the profile view.

Cheers

[fcernst]

 I'll station my alignments in the direction of flow as well...

This proposal goes against the convention for hydraulic engineers to station indivdual alignments for sewer, channels, and stream/rivers (for HEC-RAS, etc.) , from low to high.

[castled071049]

The most crucial aspect of drawing pipes is to ALWAYS DRAW THEM IN THE SAME DIRECTION. The default for the Toggle Upslope/Downslope icon in the Edit Network toolbar is set to Upstream-to-Downstream construction. Might as well use that format if you have no other preference. The stationing of the alignment, of course, makes no difference to the pipe flow direction, but in my experience most agencies prefer the alignment to start at the extreme lowpoint of the run, with stationing increasing headed upstream. 

Flow direction, which dictates flow direction in pipe labels, can be changed in the Modify Pipe Networks tab at any time. However, you cannot change the Start and End points on a pipe once they are drawn without either grip editing them (swapping end for end) or deleting the pipe and redrawing it correctly. Both of these fixes are time consuming and can wreak havoc with profiles. If you use Spanning Pipes labels to indicate slope across multiple pipes, you will get incorrect slope values if the pipes are not drawn in the same direction.

For this reason it is extremely important to pay attention to which direction you are drawing the pipes (e.g. Upstream-to-Downstream) and keep drawing them that way. 

[jalnealFG]

Not necessarily - as a rule of thumb, I draw all the pipes downhill, but generate alignments and profiles in the opposite direction.  Some of it is what you get used to, but I think it keeps with more traditional conventions.