AutoCAD

How to Remove Non Coplanar Lines in AutoCAD?

Understanding Non-Coplanar Lines in AutoCAD

Non-coplanar lines in AutoCAD indicate that certain vertices of the lines or polylines do not share the same elevation. This typically results in issues when attempting to perform operations like filleting or joining lines, as AutoCAD requires these geometric elements to exist on the same plane to function correctly. The Z-coordinates of these entities being different is the main culprit.

Identifying Non-Coplanar Lines

To determine whether lines are non-coplanar, simply examine their Z-coordinates. If some lines show varying Z-values, they are non-coplanar. The standard measure is that all points on a given line or polyline should possess the same Z-value.

Step-by-Step Process to Remove Non-Coplanar Lines

Step 1: Select the Lines

Begin by selecting all the lines or polylines that you suspect to be non-coplanar. Use the selection tool to draw a box around them or click them individually while holding the Shift key.

Step 2: Access Properties

Once the lines are selected, right-click anywhere on the highlighted section. From the context menu that appears, choose "Properties." This opens a panel that displays essential information about the selected entities.

Step 3: Modify Z-Coordinates

In the Properties panel, find the fields labeled "Start Z" and "End Z." If these fields indicate "Varies," you will need to standardize them to a single value. Input "0" or any other consistent Z-value to align the lines onto the same plane. This modification will usually resolve coplanarity issues.

Step 4: Confirm Changes

After making adjustments to the Z-values, confirm your changes by clicking out of the Properties panel. It may also be beneficial to use the "Zoom Extents" command to visually confirm that the lines now appear planar.

Step 5: Additional Techniques (If Needed)

If the issue persists, you can also employ the PEDIT command to convert multiple lines into a single polyline, further ensuring they share the same elevation.

  • Activate the command by typing PEDIT in the command line.
  • Choose “Multiple” and select the lines you modified.
  • Use the “Join” option to merge the lines.

Flattening All Lines

For a more comprehensive solution, you can flatten all lines in your drawing:

  1. Use the FLATTEN command from the command line.
  2. Select the lines or entities you wish to flatten.
  3. Confirm the operation to ensure everything is set to a consistent Z-coordinate.

FAQ

1. What causes lines to be non-coplanar in AutoCAD?

The primary cause is differences in the Z-coordinates of the line or polyline vertices, meaning the lines exist at varying elevations.

2. Can non-coplanar lines affect other AutoCAD operations?

Yes, non-coplanar lines can cause issues with commands such as fillet, chamfer, or joining, because these actions require geometric elements to lie in the same plane.

3. How can I check if my lines are still non-coplanar after adjustments?

You can select the lines and review their Z-coordinates in the Properties panel. This will help confirm if all lines now share a consistent Z value.

About the author

Wei Zhang

Wei Zhang

Wei Zhang is a renowned figure in the CAD (Computer-Aided Design) industry in Canada, with over 30 years of experience spanning his native China and Canada. As the founder of a CAD training center, Wei has been instrumental in shaping the skills of hundreds of technicians and engineers in technical drawing and CAD software applications. He is a certified developer with Autodesk, demonstrating his deep expertise and commitment to staying at the forefront of CAD technology. Wei’s passion for education and technology has not only made him a respected educator but also a key player in advancing CAD methodologies in various engineering sectors. His contributions have significantly impacted the way CAD is taught and applied in the professional world, bridging the gap between traditional drafting techniques and modern digital solutions.