# How to pick the prop in vtkAssembly

**URL:** https://discourse.vtk.org/t/how-to-pick-the-prop-in-vtkassembly/7400
**Category:** Support
**Created:** [December 14, 2021, 9:55am UTC](https://discourse.vtk.org/t/how-to-pick-the-prop-in-vtkassembly/7400 "2021-12-14T09:55:55Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![zhang-qiang-github](https://discourse.vtk.org/user_avatar/discourse.vtk.org/zhang-qiang-github/32/2519_2.png) [@zhang-qiang-github](https://discourse.vtk.org/u/zhang-qiang-github)
#### Post date: [December 14, 2021, 9:55am UTC](https://discourse.vtk.org/t/how-to-pick-the-prop-in-vtkassembly/7400/1 "2021-12-14T09:55:55Z")

</div>

I use `vtkAssembly` to collect some prop, but I meet problem when using `vtkPropPicker`.

For example, I use `vtkAssembly` to group two line (line1/line2), and the `vtkPropPicker` also correctly pick this `vtkAssembly`. Is there any method to know which line is picked?