# Building errors

**URL:** https://discourse.vtk.org/t/building-errors/2746
**Category:** Development
**Created:** [March 3, 2020, 2:35pm UTC](https://discourse.vtk.org/t/building-errors/2746 "2020-03-03T14:35:50Z")
**Posts on this page:** 4
**Page:** 1

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### Author: ![Nina](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/n/e68b1a/32.png) [@Nina](https://discourse.vtk.org/u/Nina)
#### Post date: [March 3, 2020, 2:35pm UTC](https://discourse.vtk.org/t/building-errors/2746/1 "2020-03-03T14:35:51Z")

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Hi,

I tried to re-implement the vtkMPUReconstruction using the slicer3D. The 3D Slicer is compiled without errors. but when I compile the method I get errors like this:

LNK2001 unresolved external symbol “public: virtual void \_\_cdeclImplicitFunction::asignValueToVoxels (float \* \* \* &,bool \* \* \* &,float \* const,float \* const,int \* const)” ( asignValueToVoxels@ImplicitFunction@@UEAAXAEAPEAPEAPEAMAEAPEAPEAPEA\_NQEAM2QEAH@Z)vtkSlicerReconstructionModuleLogic C:\visumedicalB\Reconstruction\Logic\vtkContoursImplicit.obj

and other errors which are similar.

I used visual studio 2015 to compile the 3d slicer and implement the medthod . are there any lib or include directory that i must add to the project?

Thank’s in advance for your help

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### Author: ![pieper](https://discourse.vtk.org/user_avatar/discourse.vtk.org/pieper/32/17_2.png) [@pieper](https://discourse.vtk.org/u/pieper)
#### Post date: [March 3, 2020, 3:02pm UTC](https://discourse.vtk.org/t/building-errors/2746/2 "2020-03-03T15:02:27Z")

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Probably the best place to start is to generate a [Slicer Extension](https://www.slicer.org/wiki/Documentation/Nightly/Developers/ExtensionWizard) to get the cmake structure you need.

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### Author: ![Nina](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/n/e68b1a/32.png) [@Nina](https://discourse.vtk.org/u/Nina)
#### Post date: [March 3, 2020, 3:06pm UTC](https://discourse.vtk.org/t/building-errors/2746/3 "2020-03-03T15:06:15Z")

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that is exactly what I did. i tried to implement a non optimized marching cube but I get a good results.

I do not understand where is the probleme ? Are there any slicer 3D libs or includes that i must add in my project ? because in generally The error of "unresolved external symbol " usually cause by complier can not find the lib files

 ![capture](https://discourse.vtk.org/uploads/default/original/2X/2/205e43cf83c9839702b3f36cff44750680317f28.png)

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### Author: ![efahl](https://discourse.vtk.org/user_avatar/discourse.vtk.org/efahl/32/1087_2.png) [@efahl](https://discourse.vtk.org/u/efahl)
#### Post date: [March 3, 2020, 3:45pm UTC](https://discourse.vtk.org/t/building-errors/2746/4 "2020-03-03T15:45:40Z")

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> [@Nina](#):
>
> asignValueToVoxels

Could it be as simple as the typo in the method name? Should have two 's’s: assignValueToVoxels