# Scale Mesh in Surface Toolbox Module trouble with centers

**URL:** <https://discourse.slicer.org/t/scale-mesh-in-surface-toolbox-module-trouble-with-centers/19016>\
**Category:** Support\
**Created:** [August 1, 2021, 8:03pm UTC](https://discourse.slicer.org/t/scale-mesh-in-surface-toolbox-module-trouble-with-centers/19016 "2021-08-01T20:03:36Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![apparrilla](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/apparrilla/32/9230_2.png) [@apparrilla](https://discourse.slicer.org/u/apparrilla)\
**Post date:** [August 1, 2021, 8:03pm UTC](https://discourse.slicer.org/t/scale-mesh-in-surface-toolbox-module-trouble-with-centers/19016/1 "2021-08-01T20:03:36Z")

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Hi everyone,

I´m trying to scale a model with Scale Mesh Tool of Surface Toolbox Module and I have some problem with the way it works with centers.

An example:

 ![Scale_1.PNG](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/3/0/300769bfceaa13ef486a58e153ab36e3f1411caf.jpeg)  
Red model is the result of a 2x scale operation of the yellow model.

 ![Scale_2](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/6/9/69416551b15e5368f9079802496200a438d3bc7d.png)

If I do a “Translate center to origin” operation li ke this (red is traslated model),

 ![Scale_3](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/3/0/3069d5b69e0c91a784148ae0976cdff7682f8b43.png)

Big red model is right what I need from smal red model…

Is there any way to add an options to the tool? Something like “from origin” and “from model center”. Or just fix it…

PD: Why result models form operations are all red? What does it mean?

 ![Scale_4](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/3/c/3c234716f805db8ef5583946e86c2a123e401d8d.png)

Thanks on advance!!!

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<div class="post-metadata">

**Author:** ![apparrilla](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/apparrilla/32/9230_2.png) [@apparrilla](https://discourse.slicer.org/u/apparrilla)\
**Post date:** [August 2, 2021, 9:01pm UTC](https://discourse.slicer.org/t/scale-mesh-in-surface-toolbox-module-trouble-with-centers/19016/2 "2021-08-02T21:01:57Z")

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I´ve been looking for in Slicer Github how to access this souce code but I just have found the dll of scale mesh module? Any idea how to fix it?  
Thanks on advance

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<div class="post-metadata">

**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:** [August 3, 2021, 5:39pm UTC](https://discourse.slicer.org/t/scale-mesh-in-surface-toolbox-module-trouble-with-centers/19016/3 "2021-08-03T17:39:30Z")

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The reason why scaling does not happen using some arbitrary centerpoint, such as center of gravity of a model because you would end up with intersecting models when you scale multiple models. The translation provides space for the enlarged models.

If you want to make your model centered after scaling then you can enable the Translate / Center option:

 ![image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/7/a/7a03877c7e403f378712f760e8ea73b36d08c0e3.png)

If you want to scale the model by keeping a certain point at a fixed position then you can apply a translation transform that moves the model’s coordinate system to that point, concatenate it with a scaling transform, and concatenate it with a transform that reverses the first translation.