Noob - cannot draw complete circles

I try to follow directions in videos to make a simple circle, but I only get 270 degree arcs, every time.
What’s the secret control that gets a 360 degree circle?
Sorry for such a noob question!

Well how are you trying to draw them? Just use the Circle command or in the menus Curve->Circle

I’ve tried a variety of commands, simplest being the center + radius. Others are 2point, 3point, Tangent:Vertical:Radius.

If you select the circle\arc, the object property panel (shown in the following screenshot) will tell you what type of object it is - it will be either closed curve, or open curve. If it is closed curve, it means that it is a circle and that part of the circle is not displayed. If it is open curve, it means that it is an arc and that you used Arc command, not Circle command.

Thankyou Andrew. It is a closed curve. I found an odd behavior. The undrawn quadrant shifts if I select the circle.

Hello - can you check Options > View > OpenGL page and un-check ‘GPU tessellation’ there… does that help? Can you also please run the command SystemInfo in Rhino and paste the results here?


Thankyou Pascal! That fixed it. What the heck?


Rhino 6 SR10 2018-11-7 (Rhino 6, 6.10.18311.20531, Git hash:master @ 0f9089a0035dcc6955732d57071445ecc29390f0)
Licence type: Evaluation, build 2018-11-07
License details: Cloud Zoo. In use by: John ()
Expires on: 2019-02-13

Windows 10.0 SR0.0 or greater (Physical RAM: 12Gb)
Machine name: PROCEON

AMD Radeon HD 6900 Series (OpenGL ver:4.5.13399 Compatibility Profile Context 15.201.1151.1008)

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: Height

Vendor Name: ATI Technologies Inc.
Render version: 4.5
Shading Language: 4.40
Driver Date: 11-4-2015
Driver Version: 15.201.1151.1008
Maximum Texture size: 16384 x 16384
Z-Buffer depth: 24 bits
Maximum Viewport size: 16384 x 16384
Total Video Memory: 1 GB

C:\Program Files\Rhino 6\Plug-ins\Commands.rhp “Commands” 6.10.18311.20531
C:\Program Files\Rhino 6\Plug-ins\WebBrowser.rhp “WebBrowser”
C:\Program Files\Rhino 6\Plug-ins\rdk.rhp “Renderer Development Kit”
C:\Program Files\Rhino 6\Plug-ins\RhinoScript.rhp “RhinoScript”
C:\Program Files\Rhino 6\Plug-ins\IdleProcessor.rhp “IdleProcessor”
C:\Program Files\Rhino 6\Plug-ins\RhinoRender.rhp “Rhino Render”
C:\Program Files\Rhino 6\Plug-ins\rdk_etoui.rhp “RDK_EtoUI” 6.10.18311.20531
C:\Program Files\Rhino 6\Plug-ins\rdk_ui.rhp “Renderer Development Kit UI”
C:\Program Files\Rhino 6\Plug-ins\NamedSnapshots.rhp “Snapshots”
C:\Program Files\Rhino 6\Plug-ins\Alerter.rhp “Alerter”
C:\Program Files\Rhino 6\Plug-ins\IronPython\RhinoDLR_Python.rhp “IronPython” 6.10.18311.20531
C:\Program Files\Rhino 6\Plug-ins\RhinoCycles.rhp “RhinoCycles” 6.10.18311.20531
C:\Program Files\Rhino 6\Plug-ins\Grasshopper\GrasshopperPlugin.rhp “Grasshopper” 6.10.18311.20531
C:\Program Files\Rhino 6\Plug-ins\Toolbars\Toolbars.rhp “Toolbars” 6.10.18311.20531
C:\Program Files\Rhino 6\Plug-ins\3dxrhino.rhp “3Dconnexion 3D Mouse”
C:\Program Files\Rhino 6\Plug-ins\Displacement.rhp “Displacement”
C:\Program Files\Rhino 6\Plug-ins\Calc.rhp “Calc”

Hi John - GPU Tessellation provides a performance boost when drawing (lots of) curves but it apparently is not compatible with all video card/driver combinations, Your driver is pretty old though, so getting the latest for your card from the AMD website (don’t trust Windows report on whether you have the latest) may fix it up so that you can use gpu tessellation.