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3D Pipe Tools workflow guide

Three ways to model
3D pipes in AutoCAD

Choose a manual centerline workflow, automatic fitting from point-cloud segments, or a semi-automatic aligned cross-section workflow.

10 min readManualAutomaticSemi-automatic

Quick answer

Use 3DPfcl for pipes drawn from known centerlines, 3DPfit for automatic centerline extraction from a point cloud, or 3DPalign when you want to align to a visible cross-section and fit the cylinder interactively.

Manual modelling from centerlines

Draw LINE entities along the pipe axes, use 3DPJcl to close gaps between skew centerlines, then run 3DPfcl and enter the radius or diameter. This method gives the most direct engineering control.

Image placeholderCenterlines before and cylinders after 3DPfclShow the entered diameter and identical route geometry.

3DPfit uses AutoCAD's point-cloud centerline extraction, so it requires an attached cloud and AutoCAD 2021 or later. The resulting pipe segments are native AutoCAD solids.

Video placeholder 09Point-cloud pipe fitting from first click to solid runShow three adjacent scanned pipe segments becoming cylinders, 45-60 seconds.

Prepare a clear working view

  • Crop the cloud around the pipe run so unrelated points do not obscure the pipe surface.
  • Choose a visual style and point size that makes the circular cross-section readable.
  • Confirm the pipe segment is sufficiently exposed in the scan.
  • Work in consistent drawing units before defining the radius.
Image placeholder 11Cropped scan with one clear pipe runShow enough surrounding structure for context without hiding the pipe surface.

Automatic modelling from a point cloud

  1. Run 3DPfit. AutoCAD starts its point-cloud centreline extraction.
  2. Click the first straight pipe segment in the scan.
  3. In the temporary view along the extracted axis, draw a circle over the visible pipe cross-section to define the radius.
  4. 3D Pipe Tools creates a cylinder along the extracted centerline.
  5. Click each next segment in the run. The previously defined radius is reused.
  6. Press Escape when finished. The operation remains grouped for undo.
Image placeholder 12Circle fitted to a scanned pipe cross-sectionLook directly down the pipe axis and clearly show the circle touching the scan wall.

Improve fitting accuracy

  • Fit straight sections separately; create elbows afterwards.
  • Use a cross-section with complete or nearly complete scan coverage.
  • Avoid defining the radius from insulation when the model requires the bare pipe diameter.
  • Check repeated diameters against known nominal sizes where appropriate.
  • Inspect the solid in several views instead of relying on one perspective.
Video placeholder 10Accuracy check around a fitted cylinderOrbit around the solid with the scan visible and highlight good and poor fits.

Semi-automatic cross-section fitting

Use 3DPalign when a pipe cross-section is visible but automatic extraction is unsuitable. Pick the projected axis, pick across the diameter, then optionally fit a three-point cylinder in the aligned view.

Video placeholderUse 3DPalign to fit a visible pipe cross-sectionShow both line picks, the aligned view and the fitted cylinder.

Convert solids to editable centerlines

Run 3DPCL to extract LINE entities from selected pipe cylinders. Edit, extend or realign the lines, then use 3DPfcl to rebuild cylinders at a chosen radius or diameter.

This provides a useful correction workflow when the scan-derived axis needs engineering cleanup before fittings are created.

Connect the pipe run

Once the straight cylinders are fitted and checked, use 3DPconnect for smooth or segmented elbows, then add branches, reducers and flanges as required.

Connect pipes and add fittingsElbows, T-joints, reducers and flangesExplore 3D Pipe ToolsCommands, examples and compatibility