# Wrong number of cells in Model Maker model

**URL:** <https://discourse.slicer.org/t/wrong-number-of-cells-in-model-maker-model/29282>\
**Category:** Support\
**Created:** [May 4, 2023, 6:33am UTC](https://discourse.slicer.org/t/wrong-number-of-cells-in-model-maker-model/29282 "2023-05-04T06:33:21Z")\
**Posts on this page:** 1\
**Showing post:** 4

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**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [May 6, 2023, 5:00pm UTC](https://discourse.slicer.org/t/wrong-number-of-cells-in-model-maker-model/29282/4 "2023-05-06T17:00:28Z")

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The triangles and their points are merged or duplicated as needed, so it is normal that their numbers change. For example, when you compute surface normals then you may want to merge some points but to preserve sharp edges you need to duplicate points. STL is a very limited file format, it can only store individual triangles, so when you save into this format then your mesh may need to be converted to an all-triangle mesh.

Recommendations:

- If you want to save data without changes then you need to use a more capable format than STL. VTK and VTP can store a VTK mesh without any modifications and including point and cell arrays, such as surface normals.
- Use Segmentations module for converting between labelmaps and models. It has many advantages over the legacy Model maker module.

Note that you do not need to add a new module for ACVD triangulation. Uniform remeshing by ACVD is already available in Slicer core in Surface Toolbox module:

> [@New feature: Uniform remeshing (ACVD algorithm)](https://discourse.slicer.org/t/new-feature-uniform-remeshing-acvd-algorithm/26196):
>
> Models (surface meshes) exported from image segmentation often have very high point counts, which can make visualization and further editing in external software difficult. Surface Toolbox module’s Decimate feature has been offering mesh simplification using quadric decimation and decimate pro algorithms, but these algorithms generate highly varying triangle sizes and shapes (depending on the curvature of the region), which is not ideal for some applications. We added a new Uniform remesh opti…

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