# Dealing with segmentation file (converting .vtk to .step)
**URL:** https://discourse.paraview.org/t/dealing-with-segmentation-file-converting-vtk-to-step/8108
**Category:** ParaView Support
**Created:** [October 1, 2021, 9:36am UTC](https://discourse.paraview.org/t/dealing-with-segmentation-file-converting-vtk-to-step/8108 "2021-10-01T09:36:24Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@1113](https://discourse.paraview.org/u/1113)
#### Post date: [October 1, 2021, 9:36am UTC](https://discourse.paraview.org/t/dealing-with-segmentation-file-converting-vtk-to-step/8108/1 "2021-10-01T09:36:24Z")
Hello,
I have imported .vtk file as a segmentation of skull model using ITK-SNAP program.
I want it to be saved as .step file format so as to use it for my 3d simulation program.
Is there any way to save .vtk file(it shows as volume) to .step file?
or,
is there any way to save the model filled as a volume?
I already used ‘contour’ filter but the inner side of a model was hollow - since it only captures the surface.
Any suggestions will be more than welcome!
Thanks in advance. My model is as attatched:
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [October 4, 2021, 8:31am UTC](https://discourse.paraview.org/t/dealing-with-segmentation-file-converting-vtk-to-step/8108/2 "2021-10-04T08:31:58Z")
> [@1113](#):
>
> Is there any way to save .vtk file(it shows as volume) to .step file?
No
> is there any way to save the model filled as a volume?
Your .vtk file is already a volume, what you are showing is a volume _reprensentation_ which can’t be saved in itself.
> Any suggestions will be more than welcome!
What are you trying to achieve exactly ?
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### Author:  [@1113](https://discourse.paraview.org/u/1113)
#### Post date: [October 4, 2021, 12:02pm UTC](https://discourse.paraview.org/t/dealing-with-segmentation-file-converting-vtk-to-step/8108/3 "2021-10-04T12:02:30Z")
I want to make a model for 3d simulation: this model should be importable in CAD program.
This model need to be represented just as it looks in volume representation of vtk file.
Also it needs not to be a surface mesh since the inside of the model would be hollow.
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [October 4, 2021, 12:59pm UTC](https://discourse.paraview.org/t/dealing-with-segmentation-file-converting-vtk-to-step/8108/4 "2021-10-04T12:59:07Z")
This does not make sense, you should read about volume rendering and what it is.
> **[Volume rendering](https://en.wikipedia.org/wiki/Volume_rendering)**
>
> In scientific visualization and computer graphics, volume rendering is a set of techniques used to display a 2D projection of a 3D discretely sampled data set, typically a 3D scalar field.
> A typical 3D data set is a group of 2D slice images acquired by a CT, MRI, or MicroCT scanner.
> Usually these are acquired in a regular pattern (e.g., one slice for each millimeter of depth) and usually have a regular number of image pixels in a regular pattern.
> This is an example of a regular volumetric grid,...
Your best bet would be to generate multiple isosurfaces.
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### Author:  [@1113](https://discourse.paraview.org/u/1113)
#### Post date: [October 5, 2021, 5:46am UTC](https://discourse.paraview.org/t/dealing-with-segmentation-file-converting-vtk-to-step/8108/5 "2021-10-05T05:46:05Z")
i’ll try,
thanks.
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### Author:  [@Fabricio\_Gatti](https://discourse.paraview.org/u/Fabricio_Gatti)
#### Post date: [April 28, 2022, 12:15am UTC](https://discourse.paraview.org/t/dealing-with-segmentation-file-converting-vtk-to-step/8108/6 "2022-04-28T00:15:54Z")
Hi! I’m dealing with the same problem, did you solve it?
Thanks!
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### Author:  [@1113](https://discourse.paraview.org/u/1113)
#### Post date: [April 29, 2022, 1:19pm UTC](https://discourse.paraview.org/t/dealing-with-segmentation-file-converting-vtk-to-step/8108/7 "2022-04-29T13:19:06Z")
I gave up using Paraview, i converted into stl model and just filled inside the surface using Fusion 360.