# python 3.8 wheel on Mac OS X
**URL:** https://discourse.vtk.org/t/python-3-8-wheel-on-mac-os-x/2850
**Category:** Support
**Created:** [March 18, 2020, 3:39pm UTC](https://discourse.vtk.org/t/python-3-8-wheel-on-mac-os-x/2850 "2020-03-18T15:39:42Z")
**Posts on this page:** 10
**Page:** 1
### Author:  [@noam.bern](https://discourse.vtk.org/u/noam.bern)
#### Post date: [March 18, 2020, 3:39pm UTC](https://discourse.vtk.org/t/python-3-8-wheel-on-mac-os-x/2850/1 "2020-03-18T15:39:42Z")
Hi - I’ve been trying to figure out how to get vtk to work with python 3.8, and in particular in making a wheel for easy installation. The basic vtk functionality works when compiling from source (using the patch from [https://gitlab.kitware.com/vtk/vtk/uploads/cf7f517b4f647de1997c4e8cddb54de9/0001-Compatibility-for-Python-3.8.patch](https://gitlab.kitware.com/vtk/vtk/uploads/cf7f517b4f647de1997c4e8cddb54de9/0001-Compatibility-for-Python-3.8.patch)), including the python wrapping module which allows my python application to work. I was also able to modify the wheel building infrastructure from [https://github.com/KitwareMedical/VTKPythonPackage](https://github.com/KitwareMedical/VTKPythonPackage) and got it to compile and apparently install. The changes were minimal (and I’d be happy to post the patch if it’s useful), mostly applying the source patch above, changing `venv` to `python3 -m venv`, and changing some paths and version numbers. I also created a dummy `libpython-not-needed-symbols-exported-by-interpreter` that is actually a library, not an empty file, to deal with the problems mentioned in [http://vtk.1045678.n5.nabble.com/vtk-8-2-0-rc2-problem-building-wheels-td5749301.html](http://vtk.1045678.n5.nabble.com/vtk-8-2-0-rc2-problem-building-wheels-td5749301.html).
This process creates a wheel that I can install with pip, but the resulting directory structure is very weird. When I directly install from source I get a bunch of `libvtk*.so` files in `PREFIX/lib`, and `vtk.py` and `vtkmodules` in `PREFIX/lib/python3.8/site-packages`. If I add those to DYLD\_LIBRARY\_PATH and PYTHONPATH things works fine. However, the wheel (which is installing to the Mac OS user directory PREFIX=~/Library/Python/3.8), creates a `vtk/` directory in `PREFIX/lib/python/site-packages`. In that `vtk/` directory it creates an empty stub ` __init__.py`, a bunch of `libvtk*dylib` files, and a `python3.8/site-packages` directory which containts `vtk.py` and `vtkmodules/`. With this setup I can `import vtk`, but `import vtk.util` fails with a ModuleNotFound error. I’m pretty sure that if I manually move the files into the a directory structure identical to that created by the build-from-source process, it works, so the actual library and python files are probably OK. It just looks like the wheel building process appends an extra `vtk/python3.8/site-packages` to the path, or something like that.
Is anyone still interested in creating a wheel file for vtk with python 3.8 (as that old mailing list thread suggested people were at one point)? Does anyone know how the os x wheel-creating-script (`VTKPythonPackage/scripts/macos_build_wheels.py`) decides on the directory structure?
---
### Author:  [@ben.boeckel](https://discourse.vtk.org/u/ben.boeckel)
#### Post date: [March 19, 2020, 11:49am UTC](https://discourse.vtk.org/t/python-3-8-wheel-on-mac-os-x/2850/2 "2020-03-19T11:49:05Z")
VTK now contains wheel-building logic in its own `master` branch now (9.0 will have it too). This is done so that you can build any VTK you want with whichever modules you want. I need to write docs for how to use it, but I sketched the outlines of what is necessary in this post: [https://discourse.vtk.org/t/vtkxdmf3writer-not-in-python-pypi-distribution/2470/2](https://discourse.vtk.org/t/vtkxdmf3writer-not-in-python-pypi-distribution/2470/2).
---
### Author:  [@noam.bern](https://discourse.vtk.org/u/noam.bern)
#### Post date: [March 19, 2020, 12:49pm UTC](https://discourse.vtk.org/t/python-3-8-wheel-on-mac-os-x/2850/3 "2020-03-19T12:49:42Z")
Great, thanks. I hadn’t realized that make it into master. It took me a moment to find the `VTK_WHEEL_BUILD` option, but eventually I discovered advanced mode in the ccmake interface.
---
### Author:  [@ben.boeckel](https://discourse.vtk.org/u/ben.boeckel)
#### Post date: [March 19, 2020, 12:53pm UTC](https://discourse.vtk.org/t/python-3-8-wheel-on-mac-os-x/2850/4 "2020-03-19T12:53:33Z")
No, it’s a CMake option. It’s not in the cache because it’s not really something meant to be turned on and off once the initial configure goes through since it’s effectively a completely separate build mode/structure (i.e., `make install` will not make anything useful).
---
### Author:  [@noam.bern](https://discourse.vtk.org/u/noam.bern)
#### Post date: [March 19, 2020, 12:58pm UTC](https://discourse.vtk.org/t/python-3-8-wheel-on-mac-os-x/2850/5 "2020-03-19T12:58:17Z")
Oops, race condition during the comment edit process. Thanks again.
---
### Author:  [@noam.bern](https://discourse.vtk.org/u/noam.bern)
#### Post date: [March 19, 2020, 5:37pm UTC](https://discourse.vtk.org/t/python-3-8-wheel-on-mac-os-x/2850/6 "2020-03-19T17:37:31Z")
I’ve now tested master, and it _almost_ works. The compilation and installation process appears to work fine, but the resulting installation in ~/Library seems not quite right. If I try to just run python and import vtk, I get
```
>>> import vtk
Traceback (most recent call last):
File "/Users/bernstei/Library/Python/3.8/lib/python/site-packages/vtkmodules/ __init__.py", line 13, in
from . import vtkCommonCore
ImportError: dlopen(/Users/bernstei/Library/Python/3.8/lib/python/site-packages/vtkmodules/vtkCommonCore.cpython-38-darwin.so, 2): Library not loaded: @rpath/libvtkWrappingPythonCore.1.dylib
Referenced from: /Users/bernstei/Library/Python/3.8/lib/python/site-packages/vtkmodules/vtkCommonCore.cpython-38-darwin.so
Reason: image not found
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "", line 1, in
File "/Users/bernstei/Library/Python/3.8/lib/python/site-packages/vtk.py", line 30, in
all_m = importlib.import_module('vtkmodules.all')
File "/opt/local/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/importlib/ __init__.py", line 127, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
File "/Users/bernstei/Library/Python/3.8/lib/python/site-packages/vtkmodules/ __init__.py", line 15, in
import _vtkmodules_static
ModuleNotFoundError: No module named '_vtkmodules_static'
```
If I add `~/Library/Python/3.8/lib/python/site-packages/vtkmodules` to `DYLD_LIBRARY_PATH`, it works well enough to run my application. I get the impression that ths isn’t supposed to be necessary. Should I open a github issue?
---
### Author:  [@ben.boeckel](https://discourse.vtk.org/u/ben.boeckel)
#### Post date: [March 19, 2020, 5:56pm UTC](https://discourse.vtk.org/t/python-3-8-wheel-on-mac-os-x/2850/7 "2020-03-19T17:56:04Z")
A GitLab issue is better. Could you send the output of `otool -l` output on one of the Python modules? I’m interested in the value of the `LC_RPATH` load command. It should have an entry for something like `@loader_path/../some/relative/path` which ends up resolving to where the real libraries live.
---
### Author:  [@noam.bern](https://discourse.vtk.org/u/noam.bern)
#### Post date: [March 19, 2020, 6:06pm UTC](https://discourse.vtk.org/t/python-3-8-wheel-on-mac-os-x/2850/8 "2020-03-19T18:06:27Z")
Here’s the output of `otool -l` (sorry, it won’t let me upload a file). Note that in the python 3.7 vtk 8.1 wheel the libraries were placed in `site-packages/vtk` along side ` __init__.py` and `vtkmodules/`, while now (python 3.8m, vtk master) they’re placed in `site-packages/vtkmodules/`, one directory below `vtk.py`. I’ll also open a gitlab issue.
```
_SOME_HOME_DIR_/Library/Python/3.8/lib/python/site-packages/vtkmodules/libvtkDomainsChemistry.dylib:
Mach header
magic cputype cpusubtype caps filetype ncmds sizeofcmds flags
0xfeedfacf 16777223 3 0x00 6 29 2640 0x00118085
Load command 0
cmd LC_SEGMENT_64
cmdsize 632
segname __TEXT
vmaddr 0x0000000000000000
vmsize 0x000000000003c000
fileoff 0
filesize 245760
maxprot 0x00000005
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Section
sectname __text
segname __TEXT
addr 0x0000000000005e50
size 0x000000000002ccc2
offset 24144
align 2^4 (16)
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reserved2 0
Section
sectname __stubs
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offset 207634
align 2^1 (2)
reloff 0
nreloc 0
flags 0x80000408
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reserved2 6 (size of stubs)
Section
sectname __stub_helper
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addr 0x00000000000331c8
size 0x0000000000000b00
offset 209352
align 2^2 (4)
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Section
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align 2^2 (4)
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Section
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align 2^0 (1)
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Section
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segname __TEXT
addr 0x000000000003b580
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offset 243072
align 2^2 (4)
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flags 0x00000000
reserved1 0
reserved2 0
Load command 1
cmd LC_SEGMENT_64
cmdsize 632
segname __DATA
vmaddr 0x000000000003c000
vmsize 0x0000000000006000
fileoff 245760
filesize 24576
maxprot 0x00000003
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addr 0x000000000003c000
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Section
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sectname __bss
segname __DATA
addr 0x00000000000416a0
size 0x0000000000000040
offset 0
align 2^3 (8)
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sectname __common
segname __DATA
addr 0x00000000000416e0
size 0x0000000000000008
offset 0
align 2^3 (8)
reloff 0
nreloc 0
flags 0x00000001
reserved1 0
reserved2 0
Load command 2
cmd LC_SEGMENT_64
cmdsize 72
segname __LINKEDIT
vmaddr 0x0000000000042000
vmsize 0x000000000001d000
fileoff 270336
filesize 115676
maxprot 0x00000001
initprot 0x00000001
nsects 0
flags 0x0
Load command 3
cmd LC_ID_DYLIB
cmdsize 64
name @rpath/libvtkDomainsChemistry.1.dylib (offset 24)
time stamp 1 Wed Dec 31 19:00:01 1969
current version 9.0.0
compatibility version 1.0.0
Load command 4
cmd LC_DYLD_INFO_ONLY
cmdsize 48
rebase_off 270336
rebase_size 512
bind_off 270848
bind_size 11336
weak_bind_off 282184
weak_bind_size 1008
lazy_bind_off 283192
lazy_bind_size 13544
export_off 296736
export_size 10128
Load command 5
cmd LC_SYMTAB
cmdsize 24
symoff 307672
nsyms 1305
stroff 330940
strsize 55072
Load command 6
cmd LC_DYSYMTAB
cmdsize 80
ilocalsym 0
nlocalsym 602
iextdefsym 602
nextdefsym 271
iundefsym 873
nundefsym 432
tocoff 0
ntoc 0
modtaboff 0
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extrefsymoff 0
nextrefsyms 0
indirectsymoff 328552
nindirectsyms 597
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cmd LC_UUID
cmdsize 24
uuid 45B2B59A-956C-3BF0-B6A5-F64069AC6F07
Load command 8
cmd LC_BUILD_VERSION
cmdsize 32
platform macos
sdk 10.15
minos 10.14
ntools 1
tool ld
version 530.0
Load command 9
cmd LC_SOURCE_VERSION
cmdsize 16
version 0.0
Load command 10
cmd LC_LOAD_DYLIB
cmdsize 56
name @rpath/libvtkIOLegacy.1.dylib (offset 24)
time stamp 2 Wed Dec 31 19:00:02 1969
current version 9.0.0
compatibility version 1.0.0
Load command 11
cmd LC_LOAD_DYLIB
cmdsize 64
name @rpath/libvtkIOXMLParser.1.dylib (offset 24)
time stamp 2 Wed Dec 31 19:00:02 1969
current version 9.0.0
compatibility version 1.0.0
Load command 12
cmd LC_LOAD_DYLIB
cmdsize 64
name @rpath/libvtkRenderingCore.1.dylib (offset 24)
time stamp 2 Wed Dec 31 19:00:02 1969
current version 9.0.0
compatibility version 1.0.0
Load command 13
cmd LC_LOAD_DYLIB
cmdsize 64
name @rpath/libvtkFiltersSources.1.dylib (offset 24)
time stamp 2 Wed Dec 31 19:00:02 1969
current version 9.0.0
compatibility version 1.0.0
Load command 14
cmd LC_LOAD_DYLIB
cmdsize 56
name @rpath/libvtkIOCore.1.dylib (offset 24)
time stamp 2 Wed Dec 31 19:00:02 1969
current version 9.0.0
compatibility version 1.0.0
Load command 15
cmd LC_LOAD_DYLIB
cmdsize 64
name @rpath/libvtkFiltersGeneral.1.dylib (offset 24)
time stamp 2 Wed Dec 31 19:00:02 1969
current version 9.0.0
compatibility version 1.0.0
Load command 16
cmd LC_LOAD_DYLIB
cmdsize 64
name @rpath/libvtkFiltersCore.1.dylib (offset 24)
time stamp 2 Wed Dec 31 19:00:02 1969
current version 9.0.0
compatibility version 1.0.0
Load command 17
cmd LC_LOAD_DYLIB
cmdsize 72
name @rpath/libvtkCommonExecutionModel.1.dylib (offset 24)
time stamp 2 Wed Dec 31 19:00:02 1969
current version 9.0.0
compatibility version 1.0.0
Load command 18
cmd LC_LOAD_DYLIB
cmdsize 64
name @rpath/libvtkCommonDataModel.1.dylib (offset 24)
time stamp 2 Wed Dec 31 19:00:02 1969
current version 9.0.0
compatibility version 1.0.0
Load command 19
cmd LC_LOAD_DYLIB
cmdsize 64
name @rpath/libvtkCommonTransforms.1.dylib (offset 24)
time stamp 2 Wed Dec 31 19:00:02 1969
current version 9.0.0
compatibility version 1.0.0
Load command 20
cmd LC_LOAD_DYLIB
cmdsize 56
name @rpath/libvtkCommonMisc.1.dylib (offset 24)
time stamp 2 Wed Dec 31 19:00:02 1969
current version 9.0.0
compatibility version 1.0.0
Load command 21
cmd LC_LOAD_DYLIB
cmdsize 56
name @rpath/libvtkCommonMath.1.dylib (offset 24)
time stamp 2 Wed Dec 31 19:00:02 1969
current version 9.0.0
compatibility version 1.0.0
Load command 22
cmd LC_LOAD_DYLIB
cmdsize 56
name @rpath/libvtkCommonCore.1.dylib (offset 24)
time stamp 2 Wed Dec 31 19:00:02 1969
current version 9.0.0
compatibility version 1.0.0
Load command 23
cmd LC_LOAD_DYLIB
cmdsize 56
name @rpath/libvtksys.1.dylib (offset 24)
time stamp 2 Wed Dec 31 19:00:02 1969
current version 9.0.0
compatibility version 1.0.0
Load command 24
cmd LC_LOAD_DYLIB
cmdsize 48
name /usr/lib/libc++.1.dylib (offset 24)
time stamp 2 Wed Dec 31 19:00:02 1969
current version 800.7.0
compatibility version 1.0.0
Load command 25
cmd LC_LOAD_DYLIB
cmdsize 56
name /usr/lib/libSystem.B.dylib (offset 24)
time stamp 2 Wed Dec 31 19:00:02 1969
current version 1281.0.0
compatibility version 1.0.0
Load command 26
cmd LC_RPATH
cmdsize 24
path $ORIGIN (offset 12)
Load command 27
cmd LC_FUNCTION_STARTS
cmdsize 16
dataoff 306864
datasize 792
Load command 28
cmd LC_DATA_IN_CODE
cmdsize 16
dataoff 307656
datasize 16
```
---
### Author:  [@ben.boeckel](https://discourse.vtk.org/u/ben.boeckel)
#### Post date: [March 19, 2020, 6:15pm UTC](https://discourse.vtk.org/t/python-3-8-wheel-on-mac-os-x/2850/9 "2020-03-19T18:15:27Z")
> [@noam.bern](#):
>
> cmd LC\_RPATH
> cmdsize 24
> path $ORIGIN (offset 12)
Well, this indicates that something is doing rpath logic, but not special casing macOS rpath logic and instead using typical ELF rpath placeholders instead.
---
### Author:  [@noam.bern](https://discourse.vtk.org/u/noam.bern)
#### Post date: [March 19, 2020, 6:18pm UTC](https://discourse.vtk.org/t/python-3-8-wheel-on-mac-os-x/2850/10 "2020-03-19T18:18:04Z")
[gitlab issue](https://gitlab.kitware.com/vtk/vtk/issues/17810). I’m happy to test any possible fixes. I’ll try to keep an eye on both the issue and this discourse topic.