# How to pick vtkLODProp3D?

**URL:** https://discourse.vtk.org/t/how-to-pick-vtklodprop3d/9184
**Category:** Support
**Created:** [August 22, 2022, 6:46am UTC](https://discourse.vtk.org/t/how-to-pick-vtklodprop3d/9184 "2022-08-22T06:46:34Z")
**Posts on this page:** 2
**Page:** 1

<div class="post-metadata">

### Author: ![AlexLuya](https://discourse.vtk.org/user_avatar/discourse.vtk.org/alexluya/32/4036_2.png) [@AlexLuya](https://discourse.vtk.org/u/AlexLuya)
#### Post date: [August 22, 2022, 6:46am UTC](https://discourse.vtk.org/t/how-to-pick-vtklodprop3d/9184/1 "2022-08-22T06:46:34Z")

</div>

After changing from vtkActor to vtkLODProp3D,

```auto
vtkNew<vtkPropPicker> picker;
		picker->Pick(upPos[0], upPos[1], 0, this->GetCurrentRenderer());
		if (picker->GetProp3D() == nullptr && picker->GetActor() == nullptr && picker->GetViewProp() == nullptr && picker->GetAssembly() == nullptr) {
			Logger::Info("Neither Prop3D nor assembly clicked!!!");
			return;
		}

```

As above code,all of following methods:

```auto
GetProp3D() 
GetActor() 
GetViewProp()
GetAssembly()

```

will return nullptr.

Question is how to pick up a vtkLODProp3D?

---

<div class="post-metadata">

### Author: ![AlexLuya](https://discourse.vtk.org/user_avatar/discourse.vtk.org/alexluya/32/4036_2.png) [@AlexLuya](https://discourse.vtk.org/u/AlexLuya)
#### Post date: [August 23, 2022, 6:06am UTC](https://discourse.vtk.org/t/how-to-pick-vtklodprop3d/9184/2 "2022-08-23T06:06:03Z")

</div>

It seems like those code:

| | //enable light shadow showing |
| --- | --- |
| | vtkNew shadows; |
| | vtkNew seq; |
| | vtkNew passes; |
| | passes-\>AddItem(shadows-\>GetShadowMapBakerPass()); |
| | passes-\>AddItem(shadows); |
| | seq-\>SetPasses(passes); |
| | vtkNew cameraP; |
| | cameraP-\>SetDelegatePass(seq); |
| | // tell the renderer to use our render pass pipeline |
| | vtkOpenGLRenderer _glrenderer = dynamic\_cast\<vtkOpenGLRenderer_\>(renderer.GetPointer()); |
| | glrenderer-\>SetPass(cameraP); |

Caused this problem