Extract pipes

This step extracts pipe traces from a point cloud. A pipe trace is made of a succession of contiguous pipe elements. 3 types of elements are available:

• Straight pipe: defined as a cylindrical section with a given diameter.

• Elbow: defined as a portion of a torus.

  • It is characterized by the radius of the underlying torus (called Bend radius), the Diameter of the pipe and the deviation Angle of the elbow.

  • Constraints: the Angle must lie within the interval ]0°; 180°]. The Bend radius must be strictly greater than the pipe radius.

• Reducer: defined as a junction between two parallel circular sections. The sections are not necessarily coaxial (we say that the reducer is eccentric - the amplitude is quantified by the Offset).

1. Hide / show the cloud or pipes using the bulbs. Adjust the transparency of the cloud or pipes using the sliders.

2. A toolbar is displayed in the scene to provide extraction and connection tools for pipe elements:

   1. Use Start new pipe trace to initiate a new pipe trace by extracting a straight pipe from the point cloud.

   2. Either continue the current new pipe trace or use Continue pipe trace to extend the selected pipe trace. Select one extremity of an existing pipe trace to activate this mode. The side to extend will be selected automatically according to the next seed points.

      • Elbow + Straight pipe extracts a straight pipe from selected points. Then, the extracted straight pipe will be connected with an elbow to the previous element. This extraction will therefore be constrained accordingly:

        • The elbow and its two straight pipes will have their center-lines co-planar.

        • The diameter of the previous element will be propagated.

        • Note that the angle of the elbow can be locked to a specified value or can be forced to a rounded value (from the following list: 5, 15, 22.5, 30, 45, 60, 90, 120, 135, 150, 157.5, 165, 175, 180°).

      • Reducer + Straight pipe extracts a straight pipe from selected points. Then, the extracted straight pipe will be connected with a reducer to the previous element. This extraction will therefore be constrained accordingly:

        • The axis of the extracted pipe will be collinear with the axis of the previous element.

        • Both reducer diameters will be set according to the adjacent pipes.

        • Note that the diameter 2 can be locked to constrain the extraction of the straight pipe.

        • Note that it is also possible to constrain the extraction to a symmetric reducer (both straight pipes and the reducer will be coaxial).

      • Straight pipe extracts a straight pipe from selected points. Then, the straight pipe will be connected to the previous element. The extraction will therefore be constrained accordingly:

        • The axis of the extracted pipe will be tangent to the axis of the previous element.

        • The diameter of the previous element will be propagated.

        • If it is the first element of a pipe trace, the diameter can be locked to a specified value.

        • If the previous element is also a straight pipe, both straight pipes will be merged.

      • Validate pipe trace (or press ENTER) validates the current pipe trace and exits the extraction mode.

   3. Merge pipe traces using one of the Connection modes (Connect with elbow, reducer or straight pipe). Select the extremity of the pipe trace to connect, then select the type of connection to make, and finally select the extremity of the pipe trace to connect. In order to guarantee the integrity of the resulting pipe trace, the second pipe trace selected can be diameter resized / realigned to propagate the connectivity constraints of the successive pipe elements. This realignment will be carried out in such a way as to maintain the fit of the extracted elements with the extracted points of each straight pipe.

   4. Delete: deletes the selected pipe element.

3. All previously extracted traces are displayed in the Extracted pipes list.

   • Hover over a line in the list and click the red cross to delete the whole pipe trace.

   • Click the bulb to hide / show a pipe trace.

   • Click the colored disk to change the pipe trace color in the scene.

4. If a pipe element is selected in the scene:

   1. The pipe trace containing the element will be automatically selected in the Extracted pipes list.

   2. Black arrows will be displayed in order to edit the element:

      • For reducers and straight pipes: the arrows are used to manage the length of the element along its axis. Use TAB to enter numeric values.

      • For elbows: the arrow is used to edit both adjacent straight pipes at the same time and consequently the bend radius too.

      • Thus, adjacent elements will be shortened or lengthened.

   3. Specific parameters will be displayed in the command:

      • For straight pipes: the diameter can be edited.

      • For reducers: the diameter and the second diameter can be edited. The offset can be edited only if the reducer has exactly one free extremity.

      • For elbows: the diameter and the bend radius can be edited. The angle can be edited only if the elbow has exactly one free extremity.

      • If edited, the diameter will be propagated until the next reducer. Since the bend radius of an elbow has to be larger than the pipe radius, the propagation may stop and an error message will be displayed.