# Extracted Surface Region (VTK) – Need Guidance on Smoothing & Cutting (VTK)

**URL:** https://discourse.vtk.org/t/extracted-surface-region-vtk-need-guidance-on-smoothing-cutting-vtk/15306
**Category:** Support
**Tags:** code
**Created:** [February 24, 2025, 10:45am UTC](https://discourse.vtk.org/t/extracted-surface-region-vtk-need-guidance-on-smoothing-cutting-vtk/15306 "2025-02-24T10:45:27Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![christeen](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/c/e8c25b/32.png) [@christeen](https://discourse.vtk.org/u/christeen)
#### Post date: [February 24, 2025, 10:45am UTC](https://discourse.vtk.org/t/extracted-surface-region-vtk-need-guidance-on-smoothing-cutting-vtk/15306/1 "2025-02-24T10:45:27Z")

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Hi Everyone,

I’m new to **VTK** , and I’m currently working on a project that involves surface region extraction, smoothing, and precise cutting.

### **Current Progress:**

- I have extracted the surface region from an **STL file** using **VTK** by drawing contours.
- The extracted region is saved as **vtkPolyData**.

### **Next Steps & Challenges:**

- I want to **generate a new smooth region** just above the extracted surface (with a specific thickness).
- The new region needs **smoothing** and **mesh optimization** (removing noise or irregularities).
- Finally, I need to **accurately cut portions** of this newly generated region.

### **Reference Video:**

To clarify my requirement, I’ve attached a YouTube embed link showing a similar process:

👉 [Watch from timestamp 19:14 to 21:27](https://www.youtube.com/embed/LPpRCM7dRAA?start=1154&end=1287)

### **Looking for Suggestions On:**

1. **Smoothing & Refinement:** What are the best techniques (in VTK or CGAL) to smooth the newly created layer?
2. **Region Generation:** How can I generate a new layer above the existing **vtkPolyData** with a uniform thickness (e.g., 3mm)?
3. **Cutting & Trimming:** What tools/methods in **VTK/CGAL** would be best for cutting the portion accurately?

I would greatly appreciate any insights, suggestions, or code snippets that can help me move forward.

Thanks in advance for your support!

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### Author: ![christeen](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/c/e8c25b/32.png) [@christeen](https://discourse.vtk.org/u/christeen)
#### Post date: [February 25, 2025, 11:25am UTC](https://discourse.vtk.org/t/extracted-surface-region-vtk-need-guidance-on-smoothing-cutting-vtk/15306/2 "2025-02-25T11:25:33Z")

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@lassoan @dgobbi @LucasGandel @mwestphal @ben.boeckel

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### Author: ![LucasGandel](https://discourse.vtk.org/user_avatar/discourse.vtk.org/lucasgandel/32/1831_2.png) [@LucasGandel](https://discourse.vtk.org/u/LucasGandel)
#### Post date: [March 11, 2025, 9:26am UTC](https://discourse.vtk.org/t/extracted-surface-region-vtk-need-guidance-on-smoothing-cutting-vtk/15306/3 "2025-03-11T09:26:20Z")

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Hi,

Here is a list of filters we use in similar use cases:

1. Smoothing & Refinement: vtkWindowedSincPolyDataFilter
2. Region Generation: CGAL alpha wrapping
3. Cutting & Trimming: vtkClipPolydata