# Can Shapework calculate PCA Component Scores in new cases without rebuilding a new model？

**URL:** <https://shapeworks.discourse.group/t/can-shapework-calculate-pca-component-scores-in-new-cases-without-rebuilding-a-new-model/147>\
**Category:** Uncategorized\
**Created:** [May 12, 2023, 3:20pm UTC](https://shapeworks.discourse.group/t/can-shapework-calculate-pca-component-scores-in-new-cases-without-rebuilding-a-new-model/147 "2023-05-12T15:20:39Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![xbyzju](https://avatars.discourse-cdn.com/v4/letter/x/a5b964/32.png) [@xbyzju](https://shapeworks.discourse.group/u/xbyzju)\
**Post date:** [May 12, 2023, 3:20pm UTC](https://shapeworks.discourse.group/t/can-shapework-calculate-pca-component-scores-in-new-cases-without-rebuilding-a-new-model/147/1 "2023-05-12T15:20:39Z")

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Hello everyone,

I have a question regarding the Shapework application. If I have already applied N shapes to build a shape statistical model (SSM) with Shapeworks and have created a clinical predictive model based on the PCA component scores. Now, I want to test the accuracy of clinical predictive model in new cases. Therefore, i need to calculate the PCA component scores based on the shape statistical model built before in the new cases. How should I do it? Can Shapeworks calculate PCA component scores with new cases without rebuilt a new SSM? Thank you！

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**Author:** ![amorris](https://avatars.discourse-cdn.com/v4/letter/a/73ab20/32.png) [@amorris](https://shapeworks.discourse.group/u/amorris)\
**Post date:** [May 15, 2023, 5:27pm UTC](https://shapeworks.discourse.group/t/can-shapework-calculate-pca-component-scores-in-new-cases-without-rebuilding-a-new-model/147/3 "2023-05-15T17:27:37Z")

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Yes, this can be accomplished by using the “fixed\_domans” feature. An example is provided here:

> **[Fixed Domains Ellipsoid: Shape Model on New Shapes - ShapeWorks](http://sciinstitute.github.io/ShapeWorks/latest/use-cases/multistep/fixed-domain-ellipsoid.html)**
>
> The official documentation of ShapeWorks

Essentially, you do re-run the optimization, but your original shapes are held constant (fixed), allowing the new shapes to conform to the existing shape model.

See also discussion here:

> [@Easiest way to enable fixed column within shapeworks studio?](https://shapeworks.discourse.group/t/easiest-way-to-enable-fixed-column-within-shapeworks-studio/141/2):
>
> The option is not exposed in Studio since it is a fairly advanced feature. We will add it though. It should still work as long as it’s in the spreadsheet. You may be missing the “use\_fixed\_subjects” option though. Try this: "use\_fixed\_subjects": "1", "fixed\_subjects\_column": "fixed", "fixed\_subjects\_choice": "yes"