# Measuring two specific points on the both STL models

**URL:** <https://discourse.slicer.org/t/measuring-two-specific-points-on-the-both-stl-models/29621>\
**Category:** Support\
**Created:** [May 24, 2023, 6:04am UTC](https://discourse.slicer.org/t/measuring-two-specific-points-on-the-both-stl-models/29621 "2023-05-24T06:04:11Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![wael\_telha](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/wael_telha/32/16914_2.png) [@wael\_telha](https://discourse.slicer.org/u/wael_telha)\
**Post date:** [May 24, 2023, 6:04am UTC](https://discourse.slicer.org/t/measuring-two-specific-points-on-the-both-stl-models/29621/1 "2023-05-24T06:04:11Z")

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I need a help Regarding measuring two specific points on the both STL models : the aim of the work is to measure the accuracy between virtual planning and actual surgery output. i ahve tried some steps and i need you to confirm if thecorrect or not

I started with a model registration between the pre-operative planning and post-operative model (stl)

 ![image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/d/8/d8a032da61a6f947a8f47056bd24263240ed256b.jpeg)

1. following the registration of the two models I used pick’n Point I choose the reference point ( edge of tooth) in the post-operative model T2 (REFERENCE MODEL) I made a point on the reference model at the area of interest to measure the distance between the same points between the two models and BEFORE running I chose the propagate the non- corresponding mesh.  

2. then through Model to Model Distance : the source model is the post-operative Model and the target model is the pre-operative model and the calculation was done  

3. the fourth and last step was to get the measured value through Mesh Statistics I chose the absolute value and X AXIS, Y, AND Z AXIS