If you need a clear, step‑by‑step guide to using the ANALYSISZEBRA shortcut in AutoCAD, this article explains what the command does, how to run it, the options you can set, why it may fail, alternative ways to inspect surface continuity, practical tips, and a FAQ to answer common reader questions.
What is the ANALYSISZEBRA shortcut?
The ANALYSISZEBRA command (often entered exactly as ANALYSISZEBRA at the command line) runs AutoCAD’s zebra analysis on 3D surfaces and solids. Zebra analysis projects alternating light/dark stripes onto a model to help you visually check surface continuity, curvature transitions, reflections and smoothness across edges or adjacent surfaces. It’s commonly used to detect G0/G1/G2 continuity issues on NURBS surfaces and complex 3D geometry.
Quick overview — when to use zebra analysis
- To verify smoothness between adjoining surfaces (spot creases and mismatched tangency).
- To inspect curvature flow on freeform surfaces.
- To communicate aesthetic/surface quality issues in reviews or design validation.
Step-by-step: How to use ANALYSISZEBRA
Prepare the view
- Switch to a 3D view (Orbit so you can see the surface from multiple directions).
- Use a visual style that supports surface shading (for best results use a Shaded or Realistic visual style).
Start the command
- Type ANALYSISZEBRA at the command line and press Enter.
- (Optional) Create an alias in the PGP file if you use it frequently, for example, AZ = ANALYSISZEBRA.
Select objects
- Select the 3D surface(s) or solid faces you want to analyze. Press Enter when selection is complete.
Choose analysis direction
- When prompted, pick a direction or select a reference edge/curve. Zebra stripes follow a direction vector; switching direction (for example U vs V on a NURBS surface) highlights different continuity aspects.
Adjust stripe density (if prompted)
- Set the stripe spacing or density (more stripes = finer visibility of curvature changes). Some AutoCAD versions expose a slider or numeric input; otherwise use the command prompts.
View and interpret results
- Rotate the model (Orbit) to see how stripes flow across joins. Smooth transitions indicate better tangency/curvature continuity; abrupt breaks show discontinuities or creases.
Turn off analysis
- Exit the command by pressing Esc or switching back to a normal visual style. Zebra visualization is a display analysis — it does not modify geometry.
Options and settings (what they do)
- Direction / Reference — controls the orientation of stripes. Analyzing along U or V directions of a surface can reveal different discontinuities.
- Stripe density / spacing — increases or decreases the number of stripes; higher density shows finer curvature variations.
- Visual style compatibility — zebra relies on shaded surface display; if your visual style is purely wireframe, stripes may not appear.
- Temporary display — analysis is a diagnostic overlay; it does not change the model and is not printed unless you capture an image.
Common reasons ANALYSISZEBRA doesn’t work and how to fix them
Problem: No stripes appear
- Fix: Ensure you selected a 3D surface or solid face (the command does not run on 2D geometry). Switch to a shaded Visual Style (Shaded/Realistic).
- Fix: Make sure you are in a viewport with 3D display enabled and not in 2D wireframe mode.
Problem: Stripes look incorrect or not aligned
- Fix: Re-orient the analysis direction (pick a different direction or edge). Check the object’s U/V parameterization when working with NURBS surfaces.
Problem: Only part of the model reacts
- Fix: The object may be on a frozen or turned-off layer. Unfreeze/unlock the layer. Also confirm you selected the correct faces.
Problem: Hardware/display issues
- Fix: Enable hardware acceleration in AutoCAD options or update your graphics driver. If performance is poor, reduce stripe density.
Problem: Command not found
- Fix: You might be in a drawing environment or version of AutoCAD that doesn’t include analysis tools. Switch to a 3D modeling or Visualize workspace, or check that your AutoCAD flavor supports surface analysis.
Problem: Zebra appears but can’t interpret result
- Fix: Use the command along multiple directions and combine zebra with curvature or draft analyses to confirm issues.
Alternative methods and commands
- visual styles & shaded views — use built-in visual styles (Shaded, Realistic, Conceptual) to inspect surface highlights.
- Curvature analysis (ANALYSISSURFACE / curvature display) — provides curvature maps rather than stripes (useful for quantitative assessment).
- Draft & Reflection tools — reflection lines or draft analysis can help in assessing flow and reflectivity continuity.
- Render preview — a quick render can reveal abrupt reflection changes on adjacent faces.
- External tools / other Autodesk products — products like Fusion 360, Alias or Inventor include advanced zebra and curvature evaluators for detailed surface inspection.
Tips for best results
- Work in a Shaded or Realistic visual style and a well-lit viewport to make stripes more visible.
- Increase stripe density when investigating subtle curvature changes; decrease density for a general check.
- Inspect surfaces from multiple angles and along different analysis directions (U and V).
- Ensure surface normals are consistent. Inverted normals can make zebra appear inconsistent.
- Combine zebra with curvature maps to confirm and quantify issues you visually detect.
- If you need frequent access, add a custom alias in your acad.pgp file (e.g., AZ = ANALYSISZEBRA) for faster workflow.
FAQ
Can I run ANALYSISZEBRA on a solid or only on surfaces?
Yes — you can run zebra analysis on 3D solids and surface faces. The tool analyzes the displayed faces; ensure you select the appropriate face(s) or entire solid.
How do I change the stripe spacing or density?
Depending on your AutoCAD version, the command prompts or a dialog will let you set stripe density/spacing. If not exposed, change the number of stripes by re-running the command and choosing a different density or using the analysis settings in your Visualize/Surface Analysis toolbar.
Why are zebra stripes not visible in my viewport?
Common causes: you are in a wireframe visual style, the object is 2D, the layer is frozen/off, or hardware acceleration/graphics driver issues. Switch to a shaded visual style and ensure the selected objects are 3D surfaces or faces.
Does ANALYSISZEBRA modify my geometry?
No. Zebra analysis is a diagnostic visual overlay only. It does not alter geometry or topology.
Can I print or export the zebra display?
Zebra lines are a visual display. To include them in prints or documentation, capture a screenshot or create a render/viewport image while the analysis is active.
Is there a keyboard shortcut or alias I can use?
The full command is ANALYSISZEBRA. You can create a short alias in your acad.pgp file, for example: AZ,ANALYSISZEBRA so typing AZ launches the analysis quickly.
My stripes look choppy or the analysis is slow — what can I do?
Lower the stripe density, turn off other heavy display effects, or enable hardware acceleration. Also consider isolating the object to a separate viewport or turning off other layers to improve performance.