Bug: Erasing midpoint

After creating the symmetry or rotating the curve, it is disordered after deleting the common node “the midpoint”

bug_wip-8.3dm (29.2 KB) bug_rhino7.3dm (42.9 KB)

Hello - I cannot reproduce that here so far.


very strange, I just downloaded the files that I have uploaded and they keep presenting the same error; It only remains for someone else to confirm it

Hello - can you run SystemInfo in Rhino and copy/paste the results?


Rhino 8 SR0 2020-12-8 (Rhino WIP, 8.0.20343.12315, Git hash:master @ e5f295e90ffababae1697e2ed03dbadd3390069e)
License type: Commercial, revisión 2020-12-08
License details: Stand-Alone
Expires on: 2021-01-22

Windows 10.0.18363 SR0.0 or greater (Physical RAM: 16Gb)

Computer platform: DESKTOP

Standard graphics configuration.
Primary display and OpenGL: NVIDIA GeForce GT 710 (NVidia) Memory: 2GB, Driver date: 5-15-2020 (M-D-Y). OpenGL Ver: 4.6.0 NVIDIA 446.14
> Accelerated graphics device with 3 adapter port(s)
- Windows Main Display attached to adapter port #0

OpenGL Settings
Safe mode: Off
Use accelerated hardware modes: On
Redraw scene when viewports are exposed: On

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: 5-15-2020
Driver Version:
Maximum Texture size: 16384 x 16384
Z-Buffer depth: 24 bits
Maximum Viewport size: 16384 x 16384
Total Video Memory: 2 GB

Rhino plugins that do not ship with Rhino
C:\Program Files\XirusCAD\\v6\Xirus.rhp “XirusCAD”
C:\Program Files\Bongo 2.0 (64-bit)\Rhino6\Bongo.20.rhp “Bongo 2.0”
C:\Users\W10\AppData\Roaming\Proving Ground\Conveyor\ProvingGround.ConveyorRhino\ProvingGround.ConveyorRhino.rhp “Conveyor Rhino Setup” 2020.3.8.0
C:\Program Files\ADA 3D\Mesh2Surface for Rhino 6\m2s_for_Rhino.rhp “MESH2SURFACE”
C:\Users\W10\AppData\Roaming\McNeel\Rhinoceros\7.0\Plug-ins\KeyShot9RhinoPlugin (ecfe8d1f-876a-460f-aa5e-3dd816936811)\\KeyShot9RhinoPlugin\Rhino 5.0\KeyShot9RhinoPlugin.rhp “KeyShot9RhinoPlugin”

Rhino plugins that ship with Rhino
C:\Program Files\Rhino 8 WIP\Plug-ins\Commands.rhp “Commands” 8.0.20343.12315
C:\Program Files\Rhino 8 WIP\Plug-ins\rdk.rhp “Renderer Development Kit”
C:\Program Files\Rhino 8 WIP\Plug-ins\RhinoRenderCycles.rhp “Rhino Render” 8.0.20343.12315
C:\Program Files\Rhino 8 WIP\Plug-ins\rdk_etoui.rhp “RDK_EtoUI” 8.0.20343.12315
C:\Program Files\Rhino 8 WIP\Plug-ins\rdk_ui.rhp “Renderer Development Kit UI”
C:\Program Files\Rhino 8 WIP\Plug-ins\NamedSnapshots.rhp “Snapshots”
C:\Program Files\Rhino 8 WIP\Plug-ins\RhinoCycles.rhp “RhinoCycles” 8.0.20343.12315
C:\Program Files\Rhino 8 WIP\Plug-ins\Toolbars\Toolbars.rhp “Toolbars” 8.0.20343.12315
C:\Program Files\Rhino 8 WIP\Plug-ins\3dxrhino.rhp “3Dconnexion 3D Mouse”
C:\Program Files\Rhino 8 WIP\Plug-ins\Displacement.rhp “Displacement”

Hello - I would block all of the ‘plug-ins that do not ship with Rhino’ in Options > Plug-ins page and then close and re-open Rhino - if things behave better, re-enable the plug-ins one at a time and restart Rhino,. test again, until you find the bad boy.

All of this running only a single instance of Rhino.


Hi @vikthor, @pascal - I can reproduce this with my own curves (degree 2 and higher) here - on deleting the central control point, the one at the right end gets deleted too. If you mirror the curves like this instead:

then it is the left end that shortens.

Unaffected by the viewport being used, curve complexity or the orientation of the mirrored curve.

(Rhino 7.2.21005.13001, 05/01/2021)


Hi Jeremy - thanks… you are running 7.2, is that correct?


Yes I am

Yep, I see this now, thanks, all - I am fairly certain it is related to the V7 changes making it possible to maintain sub-curve point structures in joined curves - this appears to be fixed in 7.3, which should be available tomorrow as a release candidate.