Missing extrusion surfaces when mirroring

Have noticed this on a number of models recently, and doing a search in the forum I notice that a similar issue occurs on windows (topic “surfaces disappear after mirroring”)

In a new file, I created a rectangle and then “extrudedcrv” to create extrusion. “Mirror” the extrusion using either the edge of the rectangle, or a different curve results in the resulting object missing it’s outer faces. However, if I click on the object to select, the lines denoting the edge of the extrusion are shown highlighted.

Software information

Software versions
Rhinoceros version: 5.0 Wenatchee 2013-10-28 (486)
OS X version: Version 10.9 (Build 13A603)


Hardware information

Computer hardware
Hardware model: iMac13,2
Processor: Intel Core i5-3470S CPU @ 2.90GHz
Memory: 8 GB
Architecture: Intel 64 bit

Video hardware
Graphics: NVIDIA GeForce GTX 660M OpenGL Engine
Memory: (null)
Screen size: 2560 x 1440
Displays: iMac

USB devices

Bluetooth devices

OpenGL information

OpenGL software
OpenGL version: 2.1 NVIDIA-8.18.22 310.40.05f01
Render version: 2.1
Shading language: 1.20
Maximum texture size: 16384 x 16384
Z-buffer depth: 24 bits
Maximum viewport size: 16384 x 16384

Implementation settings
Use texture compression: No

Appearance settings
Antialiasing: 4x
Mip map filtering: None
Anisotropic filtering: None

This has been reported on the windows side, and Pascal has logged it at http://mcneel.myjetbrains.com/youtrack/issue/RH-21732 (not visible to the public yet)


Bryan, Exploding and rejoining should clean these objects up if it is still a problem.


I thought it may have been the same issue as windows, but wasn’t sure whether it was a platform specific problem. Have tried the work around and will use that.


Had the same problem. exploding and rejoining works most of the time, so does setting the extrusion to be mirrored as a group.

We had this problem in Rhino for Windows and it’s been fixed there. When that is merged into Mac Rhino, then the fix sill show up here too.

Just part of the process. Nothing Marlin can do about it currently.