<div style="line-height:1.7;color:#000000;font-size:14px;font-family:Arial"><div style="line-height:1.7;color:#000000;font-size:14px;font-family:Arial"><div style="line-height:1.7;color:#000000;font-size:14px;font-family:Arial"><div>Hello Everyone,<br>         The error :<br>CMakeFiles/FirstReconstruction.dir/FirstReconstruction.cxx.o: In function `rtk::FDKWeightProjectionFilter<itk::Image<float, 3u>, itk::Image<float, 3u> >::BeforeThreadedGenerateData()':<br>FirstReconstruction.cxx:(.text._ZN3rtk25FDKWeightProjectionFilterIN3itk5ImageIfLj3EEES3_E26BeforeThreadedGenerateDataEv[rtk::FDKWeightProjectionFilter<itk::Image<float, 3u>, itk::Image<float, 3u> >::BeforeThreadedGenerateData()]+0x49): undefined reference to `rtk::ThreeDCircularProjectionGeometry::GetAngularGaps()' "?<br><br>can be solved as following:<br>      In the cmake interface<br>modify the version of ITK and RTK <br>In my experiment I set ITK as :  /usr/local/lib/cmake/ITK-4.7<br>                                    RTK as: /usr/local/lib/cmake/RTK-1.1<br><br>Then configure and make. All done.<br>And the FirstReconstruction ran normally and we can get the result output.mha<br><br><br><br>Thank you very much!<br><br>Houge<br><br><br></div></div></div></div>