# Modul GPA, Interactive 3D Visualization, PCA Visualization Parameters slider

**URL:** <https://discourse.slicer.org/t/modul-gpa-interactive-3d-visualization-pca-visualization-parameters-slider/46149>\
**Category:** Support\
**Created:** [February 13, 2026, 1:05pm UTC](https://discourse.slicer.org/t/modul-gpa-interactive-3d-visualization-pca-visualization-parameters-slider/46149 "2026-02-13T13:05:28Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![juliangallaun](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/juliangallaun/32/9545_2.png) [@juliangallaun](https://discourse.slicer.org/u/juliangallaun)\
**Post date:** [February 13, 2026, 1:05pm UTC](https://discourse.slicer.org/t/modul-gpa-interactive-3d-visualization-pca-visualization-parameters-slider/46149/1 "2026-02-13T13:05:28Z")

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Hello all,

I have a logical question regarding the slider increments and their relation to let’s say my PC1 axis.

I did 2D morphometric analysis in other programs (Thin plate spline) and let’s say my sample with highest PC1 score is 0.3, I can extrapolate the deformation 2x or more times (called extrapolation coefficient, if I am not mistaken), which would result in the PC1 score 0.6 for my extrapolated shape. Is it possible to get an extrapolation coefficient from the slider value?

I understand that when selecting PC1 and starting on the position 0 on the slider that this is the mean shape. But when I increase the slider to 100 in the positive direction along the PC1 where would be the data point on my PC1 axis?

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**Author:** ![muratmaga](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/muratmaga/32/3622_2.png) [@muratmaga](https://discourse.slicer.org/u/muratmaga)\
**Post date:** [February 13, 2026, 6:44pm UTC](https://discourse.slicer.org/t/modul-gpa-interactive-3d-visualization-pca-visualization-parameters-slider/46149/2 "2026-02-13T18:44:00Z")

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Magnification factor is now implemented in the GPA module. Make sure you are using the latest stable (v5.10).

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**Author:** ![juliangallaun](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/juliangallaun/32/9545_2.png) [@juliangallaun](https://discourse.slicer.org/u/juliangallaun)\
**Post date:** [February 15, 2026, 2:27pm UTC](https://discourse.slicer.org/t/modul-gpa-interactive-3d-visualization-pca-visualization-parameters-slider/46149/3 "2026-02-15T14:27:08Z")

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Thank you very much. This feature is a huge help for interpreting data.