# Tubing Design

## Main Question or Discussion Point

Hi,

When studied i found the first 3 points of the tube lie on the same plane.(attached image).
Can you please explain the reason for providing this?

Thanks

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stewartcs
Hi,

When studied i found the first 3 points of the tube lie on the same plane.(attached image).
Can you please explain the reason for providing this?

Thanks
Although I've never seen a tubing or piping isometric drawing with that notation, I would presume it is to indicate that there is no elevation change.

CS

FredGarvin
We do something very similar to this for complex tube assembly shapes on our engines. In our case, the 3D coordinate we use shows the location of bends. Usually we see an accompanying chart that lists bend radii and angles.

Why not just go to your Machinery's Handbook or if you have Marks' Standard Handbook for Mechanical Engineers that would be a start. Just viewing the Chart you supplied, the first point is the starting point of your tube while the following are the intersection points of the bends (just assuming from the chart).

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stewartcs
We do something very similar to this for complex tube assembly shapes on our engines. In our case, the 3D coordinate we use shows the location of bends. Usually we see an accompanying chart that lists bend radii and angles.
Ah, that makes sense!

CS

Sorry for the incomplete information.
Yes the points given are the intersecting points of the bend.
In the drawing they have given the bend angle, radius and also the 3d bend angle.

Please explain regarding the first 3 points i.e. A, B, C.
They lie on the same plane.
Is there any specific reason behind this?

Thanks

stewartcs
Sorry for the incomplete information.
Yes the points given are the intersecting points of the bend.
In the drawing they have given the bend angle, radius and also the 3d bend angle.

Please explain regarding the first 3 points i.e. A, B, C.
They lie on the same plane.
Is there any specific reason behind this?

Thanks
Probably due to an obstruction.

CS

When designing tubes and creating drawings there needs to be a starting point for the tube where everything begins. So, if you look at your tubing run end (doesn't matter which end) as the beginning of it's own universe where the center of the tube at that point has no value, the point would be: 0, 0, 0. everything measured from that end center point of tube then will have a value, hence the other values. I attached an example of another type of bend report but it assumes that the starting value is: 0, 0, 0.
The reason for this is so the tube manufacturer can set up their tools using the starting point given on the drawing. This probably is the easiest way to define a 3D object into 2D space by defining the start, each intersection point and the end point. Hope this helps.