Boolean Fail on MeshToNURB

Hi All,

I imported an stl file and ran MeshToNURB on the object. I have been trying to replace one section of the design but can’t seem to get a boolean difference to work. The boolean difference works on one section of the part but not on the other. I have included the sample file to show the issue.

BooleanFail.3dm (8.6 MB)

To replicate,

On the Top view select the large object and boolean difference with the cylinder on the left, result Boolean Failed.
Try again with the cylinder on the right in the top view and the boolean difference works. It would be great to get some information as to why a boolean operation would fail…

Any advice would be greatly appreciated.


Software information

Software versions
Rhinoceros version: 5.1 (5B161)
IronPython version: 5.1.2015.131
Language: en (MacOS default)
OS X version: Version 10.11.4 (Build 15E65)


Third party kernel extensions
com.3dconnexion.driver (10.2.5) 403007CA-7295-332E-9F17-DC3EA5DFD88D
org.virtualbox.kext.VBoxDrv (5.0.16) 35F02C29-8027-3636-ACD2-6F171A50C1D8
org.virtualbox.kext.VBoxUSB (5.0.16) BD2570CD-7993-3635-BE1E-FAB977FFBD5C
org.virtualbox.kext.VBoxNetFlt (5.0.16) 2C1775A7-B7A3-32A2-9E8B-951C1B499870
org.virtualbox.kext.VBoxNetAdp (5.0.16) B108642D-2C95-3CB4-8D0B-01F867E60FBF
com.paloaltonetworks.kext.pangpd (1.0.0) 92FE85C3-C89E-3FBF-A832-6D1A76B7ACA7

Hardware information

Computer hardware
Hardware model: MacBookPro11,3
Processor: Intel Core i7-4960HQ CPU @ 2.60GHz
Memory: 16 GB
Architecture: Intel 64 bit

Video hardware
Graphics: NVIDIA GeForce GT 750M 2048 MB
Memory: 2048 MB
Screen size: 1440 x 900
Displays: Color LCD (221dpi 2x)

USB devices
Apple: Card Reader
Apple Inc.: Apple Internal Keyboard / Trackpad
Apple Inc.: Bluetooth USB Host Controller

Bluetooth devices

OpenGL information

OpenGL software
OpenGL version: 2.1 NVIDIA- 310.42.25f01
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: 0x
Mip map filtering: None
Anisotropic filtering: None

Here’s some
And more

Run intersect on the two objects - you get 45 intersections. This is why MeshToNurb is not suitable to be used as a substitute for basic NURBS modeling as the first article states.


Thanks Mitch for the advice and information. I read the first article previously, but thanks for the second one, it seems to have a lot of information that I’m missing.