Why oh why do straight lines show up where curved lines should

Rhino Rhino for Windows
1

I keep running into this problem where I used curved lines to create an extrusion and the extrusion shows as a series of straight sections in the shaded view as shown here. I thought I had it solved when I set the graphics to my nvidia card instead of letting Windows choose, but here it is again in a new drawing.

image
image562×520 7.82 KB

raillings-262807-R8.3dm (3.2 MB)

Rhino 8 SR33 2026-7-7 (Rhino 8, 8.33.26188.13001, Git hash:master @ 482f88a83547c62cde64d78ea8a8690b7349f289)
License type: Commercial, build 2026-07-07
License details: Cloud Zoo

Windows 11 (10.0.26200 SR0.0) or greater (Physical RAM: 31GB)
.NET 8.0.28

Computer platform: DESKTOP

Standard graphics configuration.
Primary display and OpenGL: NVIDIA GeForce RTX 3060 (NVidia) Memory: 12GB, Driver date: 1-20-2026 (M-D-Y). OpenGL Ver: 4.6.0 NVIDIA 591.86

Accelerated graphics device with 4 adapter port(s)

  • Windows Main Display attached to adapter port #0

Secondary graphics devices.
AMD Radeon™ Graphics (AMD) Memory: 1GB, Driver date: 1-11-2024 (M-D-Y).

Accelerated graphics device with 5 adapter port(s)

  • There are no monitors attached to this device!

OpenGL Settings
Safe mode: Off
Use accelerated hardware modes: On
GPU Tessellation is: On
Redraw scene when viewports are exposed: On
Graphics level being used: OpenGL 4.6 (primary GPU’s maximum)

Anti-alias mode: 4x
Mip Map Filtering: Linear
Anisotropic Filtering Mode: High

Vendor Name: NVIDIA Corporation
Render version: 4.6
Shading Language: 4.60 NVIDIA
Driver Date: 1-20-2026
Driver Version: 32.0.15.9186
Maximum Texture size: 32768 x 32768
Z-Buffer depth: 24 bits
Maximum Viewport size: 32768 x 32768
Total Video Memory: 12 GB

Rhino plugins that do not ship with Rhino
C:\Users\Jozef\AppData\Roaming\McNeel\Rhinoceros\8.0\Plug-ins\TeDAsharp (ce983e9d-72de-4a79-8832-7c374e6e26de)\1.0.8405.22062\TeDaSharp_060.rhp “TeDAsharp” 1.0.8405.22062

Rhino plugins that ship with Rhino
C:\Program Files\Rhino 8\Plug-ins\Commands.rhp “Commands” 8.33.26188.13001
C:\Program Files\Rhino 8\Plug-ins\WebBrowser.rhp “WebBrowser”
C:\Program Files\Rhino 8\Plug-ins\rdk.rhp “Renderer Development Kit”
C:\Program Files\Rhino 8\Plug-ins\RhinoScript.rhp “RhinoScript”
C:\Program Files\Rhino 8\Plug-ins\AnimationTools.rhp “AnimationTools”
C:\Program Files\Rhino 8\Plug-ins\IdleProcessor.rhp “IdleProcessor”
C:\Program Files\Rhino 8\Plug-ins\RhinoRenderCycles.rhp “Rhino Render” 8.33.26188.13001
C:\Program Files\Rhino 8\Plug-ins\rdk_etoui.rhp “RDK_EtoUI” 8.33.26188.13001
C:\Program Files\Rhino 8\Plug-ins\NamedSnapshots.rhp “Snapshots”
C:\Program Files\Rhino 8\Plug-ins\MeshCommands.rhp “MeshCommands” 8.33.26188.13001
C:\Program Files\Rhino 8\Plug-ins\RhinoCycles.rhp “RhinoCycles” 8.33.26188.13001
C:\Program Files\Rhino 8\Plug-ins\Toolbars\Toolbars.rhp “Toolbars” 8.33.26188.13001
C:\Program Files\Rhino 8\Plug-ins\3dxrhino.rhp “3Dconnexion 3D Mouse”
C:\Program Files\Rhino 8\Plug-ins\Displacement.rhp “Displacement”
C:\Program Files\Rhino 8\Plug-ins\Calc.rhp “Calc”
C:\Program Files\Rhino 8\Plug-ins\SectionTools.rhp “SectionTools”

2

This is your meshing settings for surfaces - the curves appear to be drawn correctly.

This page is rather old and needs revising but may still be useful: Rhino Mesh Settings [McNeel Wiki]

It looks better if you use some custom meshing settings like these:

image
image838×607 16.9 KB

Setting the max dist edge to surface settings finer and the display mesh will also get progressively closer to the curve - at the expense of perhaps slowing down your display a bit.

3

Thank you.