# Create and save mesh inside of another mesh in .ply format

**URL:** https://discourse.itk.org/t/create-and-save-mesh-inside-of-another-mesh-in-ply-format/3381
**Category:** Uncategorized
**Created:** [August 11, 2020, 11:37am UTC](https://discourse.itk.org/t/create-and-save-mesh-inside-of-another-mesh-in-ply-format/3381 "2020-08-11T11:37:04Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![isuruwi](https://discourse.itk.org/letter_avatar_proxy/v4/letter/i/c0e974/32.png) [@isuruwi](https://discourse.itk.org/u/isuruwi)
#### Post date: [August 11, 2020, 11:37am UTC](https://discourse.itk.org/t/create-and-save-mesh-inside-of-another-mesh-in-ply-format/3381/1 "2020-08-11T11:37:04Z")

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I want to create and save a mesh inside of another mesh. I just create and render it as below using VTK, but how I can save this as to a single .ply file? If so how can I do that? On the other hand, I can give opacity to the cylinder through the vtkActor object. Is this possible to save it with the same configuration as including the opacity to .ply file ?  
One more thing, is that possible to add Hounsfield Unit values to each of these meshes? For example, if I assume that the sphere which is inside the cylinder as a liver and the cylinder as the air or something, how can I assign Hounsfield values to each of vertex? Is this possible ?

![combined_mesh_img](https://discourse.itk.org/uploads/default/original/2X/6/690c46f44fa9cb776f48d24ad0d2496b7a0b681a.png)

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### Author: ![dzenanz](https://discourse.itk.org/user_avatar/discourse.itk.org/dzenanz/32/1093_2.png) [@dzenanz](https://discourse.itk.org/u/dzenanz)
#### Post date: [August 17, 2020, 11:07pm UTC](https://discourse.itk.org/t/create-and-save-mesh-inside-of-another-mesh-in-ply-format/3381/2 "2020-08-17T23:07:10Z")

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This is more of a VTK question, fit for the [VTK forum](https://discourse.vtk.org/).