Commands

3DEDITBAR command in AutoCAD : Reshapes splines and NURBS surfaces, including their tangency properties

If you need a clear, step‑by‑step guide on using the 3deditbar tools in AutoCAD to reshape splines and NURBS surfaces — what the tool is, how to access and use it, why it can fail, and what alternatives to try — this article explains everything in plain English for beginners and intermediate users.

What is the 3deditbar?

The 3deditbar (also seen as the 3D Edit toolbar or legacy 3D edit tools) is a set of AutoCAD tools that let you interactively reshape splines and NURBS surfaces, including editing control vertices, isoparms, and tangency handles. It is essentially a legacy UI for tasks that let you fine‑tune curves and surface continuity.

  • It is commonly found in older or “classic” AutoCAD workspaces.
  • In recent ribbon‑based AutoCAD versions the toolbar may be hidden or removed; the underlying functions exist but may be exposed via commands, grips, the Properties palette, or the CUI (Customize User Interface).

When to use 3deditbar

Use the 3deditbar when you need to:

  • Adjust control vertices (CVs) of a spline or NURBS surface visually.
  • Change tangency and continuity at a vertex or along edges.
  • Smooth or reshape complex 3D curves and surfaces without rebuilding geometry from scratch.

How to access 3deditbar (quick methods)

If your AutoCAD doesn’t show the toolbar by default, try one of these:

  • Type TOOLBAR at the command line, press Enter, then enter: 3D Edit to show the legacy toolbar (older AutoCAD).
  • Open the CUI (Customize User Interface), locate the 3D Edit toolbar or its commands, and add it to your workspace or assign a ribbon panel/button.
  • If available in your version, switch to the 3D Modeling workspace — many 3D editing tools appear automatically.
  • If a direct toolbar/command (3deditbar) is not present, use the equivalent commands (see Alternatives below).

You can create a keyboard alias in CUI (for example map “3DEB” to a macro that opens the toolbar or runs a desired editing command) if you prefer a shortcut.

Step‑by‑step: Editing a spline/NURBS surface using the 3D edit tools

Note: exact UI steps can vary by AutoCAD version. This is a general workflow that applies whether you have the legacy toolbar or use equivalent commands/grips.

  1. Save a backup of your drawing (always). Use SAVEAS or WBLOCK to keep an original copy.
  2. Set a convenient view: enable 3DORBIT or switch to an isometric view so you can see the surface curvature.
  3. Ensure the object is editable:
    • The object must not be on a locked or frozen layer.
    • If it’s inside a block, either edit the block in Block Editor (BEDIT) or explode it if appropriate.
  4. Select the spline or NURBS surface you want to edit.
    • If the object is a polyline, convert or recreate it as a spline (use SPLINE or PEDIT → Spline).
  5. Activate the 3D editing tool:
    • Click a 3D Edit toolbar button (e.g., Edit CVs, Move CV, Insert CV, Delete CV, Adjust Tangency),
    • OR run the equivalent command (for splines: select the object and use SPLINEDIT; for surfaces use SURFEDIT or SEDIT where relevant).
  6. Enter Control Vertex (CV) mode (or display CVs):
    • CVs appear as grips/markers. Use the grips to drag CVs in 3D.
  7. Move CVs to reshape:
    • Use OSNAP, UCS, and Ortho as needed to constrain movement.
    • Use the MOVE command or drag grips to new positions. Use the 3D Move grip if moving in 3D space.
  8. Adjust tangency:
    • Use the tangency handles or tangency edit options in the tool to lengthen/shorten direction vectors for smoother joins.
  9. Insert or remove CVs:
    • Insert CVs where more control is needed; remove CVs to simplify the curve.
  10. Preview and accept changes:
    • Many editors show a preview. Confirm or commit changes, or use UNDO to revert.
  11. Fine‑tune with the Properties palette:
    • For numeric adjustments, open the Properties panel and edit knot, degree, or weight values (if applicable).
  12. Clean up:
    • Purge unused objects, and save your file.

Common 3D edit options and what they do

  • Edit CVs / Control Vertices — show points that define the curve/surface; move them to change shape.
  • Insert/Delete CV — add or remove control points to raise/lower control resolution.
  • Adjust Tangency / Continuity — modify the tangent length and direction to control G1/G2 continuity.
  • Display Isoparms — for NURBS surfaces, isoparms show surface flow lines to guide editing.
  • Rebuild / Refine — increase or decrease the number of control points and knots for smoother or simpler geometry.

Why 3deditbar sometimes doesn’t work — causes and fixes

  • Cause: Toolbar not available in ribbon workspace.

    • Fix: Use CUI to add it, or use equivalent commands (SPLINEDIT, SURFEDIT). Switch to 3D Modeling workspace.

  • Cause: Command not recognized (older command removed).

    • Fix: Use modern equivalents or run LISP/legacy support if needed. Look for the command in CUI or in command reference.

  • Cause: Object is part of a block or dynamic block.

    • Fix: Use BEDIT (Block Editor) to modify geometry inside the block, or explode the block if appropriate.

  • Cause: Layer is locked or object is on a frozen layer.

    • Fix: Unlock the layer or thaw it before editing.

  • Cause: Object is not the correct type (e.g., polyline instead of spline, imported proxy geometry).

    • Fix: Convert geometry: use SPLINE or PEDIT converting; recreate geometry if it’s proxy or cannot be edited.

  • Cause: Object is read‑only or drawing is protected.

    • Fix: Check file permissions and disable read‑only on file or drawing.

  • Cause: Grips or CVs not visible due to display or system variable settings.

    • Fix: Ensure GRIPDISPLAY = 3, GRIPS = 1, and appropriate system variables; zoom/pan in case they’re off-screen.

  • Cause: NURBS or advanced surface created in other CAD and not fully supported.

    • Fix: Convert or rebuild surface in AutoCAD, or use dedicated surface modeling software (Rhino, Fusion, etc.) for complex NURBS editing.

Alternatives to 3deditbar (built‑in and external)

Built‑in AutoCAD options:

  • SPLINEDIT — command for editing splines (insert/delete CV, convert fit points).
  • PEDIT — convert polylines to splines or edit polyline vertices.
  • GRIP editing — select curve and use grips to move control points without special toolbars.
  • Properties palette — numeric editing of control points, degree, knot vectors, weights (for certain objects).
  • SURFEDIT or SEDIT — for editing surface control vertices and isoparms.
  • Rebuild/REFINE — change spline degree or number of knots for smoother geometry.

External or other applications:

  • Use specialized NURBS editors (Rhino, Alias) when precise surface modeling and advanced NURBS control are required.
  • Use 3D CAD packages that provide advanced surfacing tools if AutoCAD’s tools are insufficient.

Practical tips and best practices

  • Always work on a copy of the geometry when performing destructive edits.
  • Use UCS to align your editing plane for easier control of CV movement in 3D.
  • Toggle isoparms and control point display to better visualize curvature.
  • Use OSNAP and 3D object snaps to position CVs precisely relative to other geometry.
  • Use Undo (CTRL+Z) frequently to compare before/after states.
  • If you need repeatable workflows, create a custom ribbon panel or CUI macro that runs your preferred edit commands.
  • Keep your workspace organized — enable the Properties palette and the Tool Palettes to access editing controls quickly.
  • When joining curves/surfaces, consider adjusting tangency and continuity (G1/G2) to avoid visible seams.

FAQ

How do I know if my AutoCAD version supports the 3D Edit toolbar?

Many modern AutoCAD releases shifted away from legacy toolbars. If typing TOOLBAR or opening CUI shows a 3D Edit toolbar, it’s available. Otherwise, use equivalent commands like SPLINEDIT and SURFEDIT or enable the classic workspace if your installation includes it.

Can I edit spline control vertices without 3deditbar?

Yes — use grip editing (select the spline and drag grips), SPLINEDIT, or the Properties palette to change vertex coordinates and weights numerically.

My 3D edit tools don’t show control points — how do I display them?

Make sure the object is a spline/NURBS, the layer isn’t locked, and grips are enabled (check GRIPS system variable). Use SPLINEDIT or SURFEDIT to force display of control vertices.

The object seems uneditable after importing from another CAD system. What can I do?

Imported NURBS may be represented as proxy geometry. Try converting the object to native AutoCAD geometry (rebuild or recreate), or use the original authoring software for complex NURBS edits. You can also try exporting the object to SAT/STEP and reimporting, then rebuilding surfaces in AutoCAD.

How can I edit tangency or continuity precisely (numeric control)?

Use the Properties palette (with the object selected) for numeric tangency/weight/knot editing when available. For finer control, consider rebuilding the curve with a specified degree and knot vector, or use surfacing tools that expose continuity settings.

The toolbar is there but clicking buttons does nothing — what next?

Check for command conflicts or missing support files. Restart AutoCAD, reset the workspace, or restore a default CUI profile. If certain commands are missing, repair or reinstall AutoCAD, or copy necessary toolbar items from a working CUI file.

Is there a keyboard shortcut for 3deditbar functions?

Not by default. You can create aliases or keyboard shortcuts via CUI to run specific 3D edit commands (for example, map an alias to run SPLINEDIT or a macro that opens the toolbar).

Should I use AutoCAD or a dedicated surfacing tool for complex NURBS?

For advanced NURBS surfacing and highly precise continuity control, dedicated surfacing tools (Rhino, Alias, etc.) are often more powerful. Use AutoCAD for simpler edits and integration with drafting workflows.

You may also like