# Moving polydata (opened .stl files) around using transforms

**URL:** <https://discourse.slicer.org/t/moving-polydata-opened-stl-files-around-using-transforms/7887>\
**Category:** Support\
**Tags:** dicom, transforms, openigtlink\
**Created:** [August 5, 2019, 8:02pm UTC](https://discourse.slicer.org/t/moving-polydata-opened-stl-files-around-using-transforms/7887 "2019-08-05T20:02:23Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Renjie\_Zhu](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/renjie_zhu/32/4333_2.png) [@Renjie\_Zhu](https://discourse.slicer.org/u/Renjie_Zhu)\
**Post date:** [August 5, 2019, 8:02pm UTC](https://discourse.slicer.org/t/moving-polydata-opened-stl-files-around-using-transforms/7887/1 "2019-08-05T20:02:23Z")

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Operating system: Ubuntu 18.04  
Slicer version: 4.8.1  
Expected behavior: Move an .stl polydata around in the 3d view  
Actual behavior:

Hi, I want to create an overlay of a needle both on the 3d view and the 2d slices. I have tried to use fiducials by sending a pointcloud over OpenIGTLink but when the number of fiducials goes up the app becomes significantly laggy. I figured that by using a polydata overlay, I can both see the shape in the 3d view and see an intersection with actual dicom slices in the 2d slices viewer.

The problem I am facing is that I want to move this polydata thing around (changing its position and orientation), preferrably with transforms as I can easily send transforms over from ROS using OpenIGTLink.

Any help will be very much appreciated!

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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:** [August 5, 2019, 8:13pm UTC](https://discourse.slicer.org/t/moving-polydata-opened-stl-files-around-using-transforms/7887/2 "2019-08-05T20:13:00Z")

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You can receive transforms via OpenIGTLink and apply it to any node (in Transforms module). Use at least the latest Stable Release of Slicer. See tutorials at [www.slicerigt.org](http://www.slicerigt.org).

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**Author:** ![Renjie\_Zhu](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/renjie_zhu/32/4333_2.png) [@Renjie\_Zhu](https://discourse.slicer.org/u/Renjie_Zhu)\
**Post date:** [August 5, 2019, 8:58pm UTC](https://discourse.slicer.org/t/moving-polydata-opened-stl-files-around-using-transforms/7887/3 "2019-08-05T20:58:37Z")

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Thank you for your help! So I just add the model as a transformable, is that correct?

I use 4.8.1 as the OpenIGTLink bridge with ROS has problems communicating correctly. So I was suggested by the author of that module to use an older version. I will test if this works in 4.10.2.

Thank you again.