# vtkOBJImporter load data, and how to get the color of point, and change some of the cells' color by SetScalars?

**URL:** https://discourse.vtk.org/t/vtkobjimporter-load-data-and-how-to-get-the-color-of-point-and-change-some-of-the-cells-color-by-setscalars/12891
**Category:** Support
**Tags:** python, code
**Created:** [December 13, 2023, 7:44am UTC](https://discourse.vtk.org/t/vtkobjimporter-load-data-and-how-to-get-the-color-of-point-and-change-some-of-the-cells-color-by-setscalars/12891 "2023-12-13T07:44:48Z")
**Posts on this page:** 1
**Showing post:** 4

<div class="post-metadata">

### Author: ![yangyang117](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/y/da6949/32.png) [@yangyang117](https://discourse.vtk.org/u/yangyang117)
#### Post date: [January 8, 2024, 9:06am UTC](https://discourse.vtk.org/t/vtkobjimporter-load-data-and-how-to-get-the-color-of-point-and-change-some-of-the-cells-color-by-setscalars/12891/4 "2024-01-08T09:06:37Z")

</div>

Hi, Andras, I’m using vtk to get the threshold segment and translate it to polydata. But here is some problems, Can you see it? Thank you.  
If possible, Can you give me how slicer process this flow?(Get the CT, threshold, translate to polydata?)

here is the link:

> [@Use threshold for the CT Segment and translate the labelmap to polydata](https://discourse.vtk.org/t/use-threshold-for-the-ct-segment-and-translate-the-labelmap-to-polydata/13028):
>
> Hi, I’m using threshold for a CT’s bone surface, and using vtkDiscreteMarchingCubes to get the first polydata,but the data is too large,when I use vtkQuadricDecimation to reduce the number of cells, but there will have some holes and non manifold edges. I have no idea how to solve the problem. ① should I smooth the CT before the threshold? ② how to reduce the number of cells without the holes or non manifold edges appear? ③ Is there parameters that I should set when using the vtkDiscreteMarc…

---

_[View the full topic](https://discourse.vtk.org/t/vtkobjimporter-load-data-and-how-to-get-the-color-of-point-and-change-some-of-the-cells-color-by-setscalars/12891)._