# Calculate the porosity and surface roughness of the powder layer
**URL:** https://discourse.paraview.org/t/calculate-the-porosity-and-surface-roughness-of-the-powder-layer/13362
**Category:** ParaView Support
**Created:** [November 28, 2023, 8:43am UTC](https://discourse.paraview.org/t/calculate-the-porosity-and-surface-roughness-of-the-powder-layer/13362 "2023-11-28T08:43:33Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@MuWeihao](https://discourse.paraview.org/u/MuWeihao)
#### Post date: [November 28, 2023, 8:43am UTC](https://discourse.paraview.org/t/calculate-the-porosity-and-surface-roughness-of-the-powder-layer/13362/1 "2023-11-28T08:43:33Z")
Hello!
I want to analyze the porosity and the surface roughness of the powder layer.
The critical step is to **calculate the volume of powders in the extract region** and **export the powder information (including the location of each powder and the radius of each powder)**, but I have no idea how to implement it. Can anyone give me some advice?
Moreover, the version of Paraview is 5.12.0-RC1-Windows, and the DEM simulation result is calculated by Yade. The vtk files are uploaded in depo.zip.
Thank you!
[depo.zip](https://discourse.paraview.org/uploads/short-url/juI474GFX5L2k5sZrLnfV4cgt6m.zip) (54.0 KB)
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### Author:  [@MuWeihao](https://discourse.paraview.org/u/MuWeihao)
#### Post date: [November 28, 2023, 1:46pm UTC](https://discourse.paraview.org/t/calculate-the-porosity-and-surface-roughness-of-the-powder-layer/13362/2 "2023-11-28T13:46:26Z")
Hello everyone. I can obtain the data of the particles (including position and radius) by opening the depo-sphere.vtk file in the Notepad but calculating the volume of the particles in the extract region by this method is relatively complicated, I would like to ask you if there is a convenient method that can address this problem in Paraview.
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### Author:  [@spyridon97](https://discourse.paraview.org/u/spyridon97)
#### Post date: [November 28, 2023, 4:18pm UTC](https://discourse.paraview.org/t/calculate-the-porosity-and-surface-roughness-of-the-powder-layer/13362/3 "2023-11-28T16:18:44Z")
Maybe you should check if `Compute Connected Surface Properties` filter.
Its description is:
```auto
Given a PolyData, computed the volume, area and centroid of one or more polygonal objects.
An optional object IDs cell data array that maps a polygon to a specific object may be provided,
or the objects will be identified as connected components in the input data.
```
But since you probably have a volume mesh, use `Extract Surface` and then `Compute Connected Surface Properties`.
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### Author:  [@MuWeihao](https://discourse.paraview.org/u/MuWeihao)
#### Post date: [November 30, 2023, 3:04am UTC](https://discourse.paraview.org/t/calculate-the-porosity-and-surface-roughness-of-the-powder-layer/13362/4 "2023-11-30T03:04:35Z")
Thank you for your advice, that really helped me.
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### Author:  [@spyridon97](https://discourse.paraview.org/u/spyridon97)
#### Post date: [November 30, 2023, 4:55am UTC](https://discourse.paraview.org/t/calculate-the-porosity-and-surface-roughness-of-the-powder-layer/13362/5 "2023-11-30T04:55:42Z")
I am glad i could be of help!