Can I show the ʼZebraʼ stripes on a surface to check for smoothness in Rhinoceros 3D?
Short Answer
Yes — in Rhino 3D, you can show zebra stripes on a surface to check continuity and smoothness using the Zebra analysis command. This is the most common professional method for visually evaluating reflections across adjacent surfaces. Limitation: Zebra is visual analysis, so it does not numerically confirm curvature continuity.
What You Need to Know Before
Warning: Zebra stripes can look acceptable even when tiny edge mismatches or poor control-point structure still exist. A common failure is judging a bad Class-A transition as “smooth” because the stripe scale or direction is not revealing the defect clearly.
How to Show Zebra Stripes in Rhino 3D
Command: Zebra
Shortcut: No default shortcut
Quick Steps:
- Select the surface or polysurface, then go to Analyze > Surface > Zebra.
- In the Zebra options, set a real display option such as Horizontal/Vertical direction or adjust the stripe count/size.
- Inspect how the stripes flow across the surface edges; smooth, continuous stripe transitions usually indicate better surface continuity.
Variables & Settings
Key Setting: Zebra direction and stripe spacing
Expert Setting: Changing the stripe direction can reveal defects that are hidden in one orientation. Wider or fewer stripes may hide subtle waviness, while tighter stripes make small continuity problems easier to see.
Why it Fails
Cause 1 (Geometry): The surface may have tangent breaks, poor edge matching, or uneven control points that create broken or pinched stripe flow.
Cause 2 (layers/Locks): The target object may be on a locked layer or mixed with other visible geometry, making the Zebra analysis harder to isolate and read.
Cause 3 (Command/Logic): Zebra only shows reflective continuity visually; it does not replace checking edge matching with commands like curvature or continuity analysis.
Quick Fix & Best Practice
Quick Fix: Run MatchSrf on adjacent surfaces, then recheck them with Zebra using a different stripe direction.
Manager’s Verdict: Use Zebra early and often for fast visual surfacing checks, especially on consumer-product shapes. Avoid relying on it alone when production-quality continuity must be validated.
FAQ
Can Zebra work on joined polysurfaces in Rhino 3D?
Yes, Zebra can be displayed on polysurfaces to inspect reflection flow across joined faces.
Is Zebra better than curvature analysis?
No, Zebra is faster for visual checking, while curvature analysis is better for technical continuity evaluation.
Can I change the stripe orientation in Zebra?
Yes, Rhino lets you change the stripe direction to reveal different surface defects.
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