# ParaView plugin project structure
**URL:** https://discourse.paraview.org/t/paraview-plugin-project-structure/6398
**Category:** Development
**Created:** [February 5, 2021, 10:18am UTC](https://discourse.paraview.org/t/paraview-plugin-project-structure/6398 "2021-02-05T10:18:19Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@PetiteViking](https://discourse.paraview.org/u/PetiteViking)
#### Post date: [February 5, 2021, 10:18am UTC](https://discourse.paraview.org/t/paraview-plugin-project-structure/6398/1 "2021-02-05T10:18:20Z")
Hi,
I am currently trying to make the switch from Inviwo to Paraview but the Plugin/module structure seems to elude me.
The project structure I have so far looks like as shown below. I have more filters but for the sake of simplicity I’ll only go through one here. The code is available at [OpenTensorVis](https://github.com/JochenJankowai/OpenTensorVis/tree/master/paraview/OpenTensorVis).
```auto
├── CMakeLists.txt
├── OpenTensorVis
│ ├── CMakeLists.txt
| |── opentensorvis.plugin
│ ├── TensorFieldCriticalCellsFilter
│ │ ├── CMakeLists.txt
│ │ ├── tensorfieldcriticalcells.module
│ │ ├── TensirFieldCriticalCellsFilter.xml
│ │ ├── vtkTensorFieldCriticalCells.cxx
│ │ └── vtkTensorFieldCriticalCells.h
```
The top level `CMakeLists.txt` contains
```auto
cmake_minimum_required(VERSION 3.8)
project(OpenTensorVis-ParaView-Plugins)
find_package(ParaView REQUIRED)
set(CMAKE_CXX_STANDARD 20)
option(BUILD_SHARED_LIBS "Build shared libraries" ON)
include(GNUInstallDirs)
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/${CMAKE_INSTALL_BINDIR}")
set(CMAKE_LIBRARY_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/${CMAKE_INSTALL_LIBDIR}")
set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/${CMAKE_INSTALL_LIBDIR}")
set("_paraview_plugin_default_${CMAKE_PROJECT_NAME}" ON)
paraview_plugin_scan(
PLUGIN_FILES "${CMAKE_CURRENT_SOURCE_DIR}/OpenTensorVis/opentensorvis.plugin"
PROVIDES_PLUGINS opentensorvis
REQUIRES_MODULES required_modules)
foreach (module IN LISTS required_modules)
if (NOT TARGET "${module}")
message(#FATAL_ERROR
"Skipping example ${CMAKE_PROJECT_NAME}: Missing required module: "
"${module}")
return ()
endif ()
endforeach ()
paraview_plugin_build(
RUNTIME_DESTINATION "${CMAKE_INSTALL_BINDIR}"
LIBRARY_DESTINATION "${CMAKE_INSTALL_LIBDIR}"
LIBRARY_SUBDIRECTORY "${PARAVIEW_PLUGIN_SUBDIR}"
PLUGINS ${opentensorvis})
```
The `opentensorvis.plugin` file:
```auto
NAME
OpenTensorVis
DESCRIPTION
Implementations of the algorithms and methods developed in the OpenTensorVis project.
REQUIRES_MODULES
VTK::CommonCore
VTK::FiltersCore
```
The `CMakeLists.txt` for the plugin simply contains
```auto
paraview_add_plugin(OpenTensorVis
VERSION "1.0"
MODULES
OpenTensorVis::TensorFieldCriticalCellsFilter
MODULE_FILES
"${CMAKE_CURRENT_SOURCE_DIR}/TensorFieldCriticalCellsFilter/tensorfieldcriticalcells.module"
)
```
Last but not least, the `tensorfieldcriticalcells.module` file defines a simple module:
```auto
NAME
OpenTensorVis::TensorFieldCriticalCellsFilter
LIBRARY_NAME
vtkTensorFieldCriticalCellsFilter
DEPENDS
VTK::FiltersCore
PRIVATE_DEPENDS
VTK::CommonCore
```
with a corresponding `CMakeLists.txt`:
```auto
set(vtkTensorFieldCriticalCellsClasses
vtkTensorFieldCriticalCells)
vtk_module_add_module(OpenTensorVis::TensorFieldCriticalCellsFilter
CLASSES ${vtkTensorFieldCriticalCellsClasses})
paraview_add_server_manager_xmls(
XMLS TensorFieldCriticalCellsFilter.xml
)
```
CMake runs fine and everything compiles but when trying to load the plugin, ParaView throws the error
```auto
ERROR: In C:\bbd\6c27b535\build\superbuild\paraview\src\Remoting\Core\vtkPVPluginLoader.cxx, line 519
vtkPVPluginLoader (000001D855F1F2F0): The specified module could not be found.
```
I suppose I am mixing things up somewhere and I’d be happy about pointers as to where to look. Thanks!
---
### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [February 5, 2021, 10:20am UTC](https://discourse.paraview.org/t/paraview-plugin-project-structure/6398/2 "2021-02-05T10:20:40Z")
You are not loading the right .so file, it is deeper in the build.
Modify your `CMakeLists.txt` like this to avoid this issue and generate a single .so file.
```auto
set(vtkTensorFieldCriticalCellsClasses
vtkTensorFieldCriticalCells)
vtk_module_add_module(OpenTensorVis::TensorFieldCriticalCellsFilter
FORCE_STATIC
CLASSES ${vtkTensorFieldCriticalCellsClasses})
paraview_add_server_manager_xmls(
XMLS TensorFieldCriticalCellsFilter.xml
)
```
---
### Author:  [@PetiteViking](https://discourse.paraview.org/u/PetiteViking)
#### Post date: [February 5, 2021, 11:49am UTC](https://discourse.paraview.org/t/paraview-plugin-project-structure/6398/3 "2021-02-05T11:49:19Z")
Hi,
thanks for the quick reply. I tried it out but ParaView throws the same error.
I’m just groping in the dark here but could the namespace in `OpenTensorVis::TensorFieldCriticalCellsFilter` cause trouble? Or the fact that the plugin is called OpenTensorVis and the namespace as well?
---
### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [February 5, 2021, 11:50am UTC](https://discourse.paraview.org/t/paraview-plugin-project-structure/6398/4 "2021-02-05T11:50:09Z")
maybe, it is hard to say. I’d suggest trying with one the example that has a similar architecture and expand from there.
---
### Author:  [@ben.boeckel](https://discourse.paraview.org/u/ben.boeckel)
#### Post date: [February 5, 2021, 2:38pm UTC](https://discourse.paraview.org/t/paraview-plugin-project-structure/6398/5 "2021-02-05T14:38:25Z")
Does `ldd` have all libraries satisfied when you run it on the plugin that you’re trying to load? If not, you may be missing RPATH information somewhere. The output of `readelf -d` on the file may help there too.