TestZBiasFactor No Longer Working

Hi Everyone,

It feels like every 2 years I look for a solution for edges of objects being seen through other objects/surfaces. TestZBiasFactor used to be the band-aid for this problem, but I’m finding that it’s not working in the later releases of Rhino6. If it was just an issue in the viewport I could live with it, but it shows up in my prints as well. I attached example images and system info. It starts happening at mid to long distances from objects.

I’m wondering if the issue is happening because my graphics card doesn’t support a higher resolution depth buffer that Rhino has added in its later releases. (I have a Maxwell TitanX).

Thanks for any help/ solutions for this issue.

Rhino 6 SR21 2019-12-17 (Rhino 6, 6.21.19351.09141, Git hash:master @ 4d373f64ffb55e3a8d607d9618590728d86fb1e9)
License type: Commercial, build 2019-12-17
License details: Cloud Zoo. In use by: JRT ()

Windows 10.0 SR0.0 or greater (Physical RAM: 64Gb)
Machine name: JRT

Non-hybrid graphics.
Primary display and OpenGL: NVIDIA GeForce GTX TITAN X (NVidia) Memory: 12GB, Driver date: 9-5-2019 (M-D-Y). OpenGL Ver: 4.6.0 NVIDIA 436.30

Secondary graphics devices.
NVIDIA GeForce GTX TITAN X (NVidia) Memory: 12GB, Driver date: 9-5-2019 (M-D-Y).

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

Anti-alias mode: 8x
Mip Map Filtering: Linear
Anisotropic Filtering Mode: Height

Vendor Name: NVIDIA Corporation
Render version: 4.6
Shading Language: 4.60 NVIDIA
Driver Date: 9-5-2019
Driver Version:
Maximum Texture size: 16384 x 16384
Z-Buffer depth: 24 bits
Maximum Viewport size: 16384 x 16384
Total Video Memory: 12 GB

Rhino plugins
C:\Program Files\Geometry Gym\Rhino3d\ggRhinoIFC.rhp “ggRhinoIFC”
C:\Program Files\Rhino 6\Plug-ins\Commands.rhp “Commands” 6.21.19351.9141
C:\Program Files\Geometry Gym\Rhino3d\BullAnt.rhp “bullant”
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\RPC.rhp “RPC”
C:\Program Files\Rhino 6\Plug-ins\AnimationTools.rhp “AnimationTools”
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” 6.21.19351.9141
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\RhinoCycles.rhp “RhinoCycles” 6.21.19351.9141
C:\Program Files\Rhino 6\Plug-ins\Toolbars\Toolbars.rhp “Toolbars” 6.21.19351.9141
C:\Program Files\Rhino 6\Plug-ins\3dxrhino.rhp “3Dconnexion 3D Mouse”
C:\Program Files\Rhino 6\Plug-ins\Displacement.rhp “Displacement”

maybe this thread helps a bit:

Hello - it does depend on the overall size of the scene - are these scenes large in extent?


Thanks for your responses

@Gijs, Yeah, that’s about where I ended up last time I looked into this. I didn’t know if the depth buffer precision was improved but doesn’t agree with my GPU.

@ Pascal, it’s pretty big, the perimeter of all objects is 380’x400’.


@pascal, do you know if Mcneel intends to improve the resolution of the depth buffer any time soon (assuming it hasn’t been addressed)?

Hello - I have no idea whether that is up to us, or OpenGL, or what… @jeff will know…


Is there a work-around for this or an underlying issue causing the problem that I’m missing?. I can’t even print from Rhino anymore because the artifacts are so prevalent. (see below)

Hello - I would at least try hiding stuff that makes the scene large in extents, outside the are you are printing and see if that even makes a difference. I could be wrong but my suspicion is it (problem) has to do with the size.


The last image I attached was from a scene with only 1 object in it and I’m working off the world center. The extents are now pretty average in size and similar to what I use when I don’t experience this issue. It was also exported into a fresh scene. I’ve tried several different GPU drivers as well.

Is this a standard Perspective view projection, or a Parallel, or Two Point Perspective?

Hello - can you please post or send us that smaller file (tech@mcneel.com) with a link back here in your comments.



@pascal, sure thing, the file has been sent to the requested email address with a link back to this discussion. Thank you for looking into this.

@John_Brock. sorry I didn’t see your comment. This happens all the projections you mentioned. It doesn’t occur in standard orthographic views.