# cmake-changes in vtk9.0.1 (occt build error)

**URL:** https://discourse.vtk.org/t/cmake-changes-in-vtk9-0-1-occt-build-error/3736
**Category:** Support
**Created:** [July 9, 2020, 8:24am UTC](https://discourse.vtk.org/t/cmake-changes-in-vtk9-0-1-occt-build-error/3736 "2020-07-09T08:24:09Z")
**Posts on this page:** 4
**Page:** 1

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### Author: ![looooo](https://discourse.vtk.org/user_avatar/discourse.vtk.org/looooo/32/2070_2.png) [@looooo](https://discourse.vtk.org/u/looooo)
#### Post date: [July 9, 2020, 8:24am UTC](https://discourse.vtk.org/t/cmake-changes-in-vtk9-0-1-occt-build-error/3736/1 "2020-07-09T08:24:09Z")

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Please somebody involved in vtk-development can give a hint what cmake changes were added in vtk9.  
We are running into:

CMake Error at CMakeLists.txt:730 (message):  
Could not find headers of used third-party products:  
3RDPARTY\_VTK\_INCLUDE\_DIR

with occt7.4 which worked previously with vtk8.

> <https://github.com/conda-forge/occt-feedstock/pull/44>

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### Author: ![ben.boeckel](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/b/ea5d25/32.png) [@ben.boeckel](https://discourse.vtk.org/u/ben.boeckel)
#### Post date: [July 9, 2020, 2:32pm UTC](https://discourse.vtk.org/t/cmake-changes-in-vtk9-0-1-occt-build-error/3736/2 "2020-07-09T14:32:42Z")

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That variable looks like an occt variable, not VTK. Please file an issue against occt (feel free to mention me if they’re on github: `@mathstuf`).

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### Author: ![looooo](https://discourse.vtk.org/user_avatar/discourse.vtk.org/looooo/32/2070_2.png) [@looooo](https://discourse.vtk.org/u/looooo)
#### Post date: [July 13, 2020, 7:28am UTC](https://discourse.vtk.org/t/cmake-changes-in-vtk9-0-1-occt-build-error/3736/3 "2020-07-13T07:28:33Z")

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thanks for the reply.  
sure it is related to occt, but as the vtk-configuration worked previously it would be nice to know which parts of vtk-cmake have changed. A short hint might help to create a patch to fix the vtk configuration.

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### Author: ![ben.boeckel](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/b/ea5d25/32.png) [@ben.boeckel](https://discourse.vtk.org/u/ben.boeckel)
#### Post date: [July 15, 2020, 4:18pm UTC](https://discourse.vtk.org/t/cmake-changes-in-vtk9-0-1-occt-build-error/3736/4 "2020-07-15T16:18:24Z")

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[These docs](https://vtk.org/doc/nightly/html/md__home_kitware_dashboards_buildbot_vtk_nightly-master-ike-linux-shared-release_doc_nightly_osm5be4e3c8a508a13e731d7b85aeec815a.html) should be a good start.