# 3D View Lag when Hundreds of Models Loaded and OpenIGTLinkIF Running

**URL:** <https://discourse.slicer.org/t/3d-view-lag-when-hundreds-of-models-loaded-and-openigtlinkif-running/12792>\
**Category:** Support\
**Created:** [July 30, 2020, 3:48pm UTC](https://discourse.slicer.org/t/3d-view-lag-when-hundreds-of-models-loaded-and-openigtlinkif-running/12792 "2020-07-30T15:48:23Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Ryan\_Morrison](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/ryan_morrison/32/7508_2.png) [@Ryan\_Morrison](https://discourse.slicer.org/u/Ryan_Morrison)\
**Post date:** [July 30, 2020, 3:48pm UTC](https://discourse.slicer.org/t/3d-view-lag-when-hundreds-of-models-loaded-and-openigtlinkif-running/12792/1 "2020-07-30T15:48:23Z")

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Slicer Version: 4.11.0  
PC: Windows 10, AMD 8320, 8Gb RAM, GTX660ti 3Gb

My issue comes in the second I turn on [OpenIGTLinkIF](http://www.slicerigt.org/wp/) to view live [motion tracker data](https://www.ndigital.com/msci/products/drivebay-trakstar/) when ~500 models are loaded into the 3D View. Slicer lags significantly ([video](https://youtu.be/cgYqOi3Z6d0)). If only a few models are loaded, slicer very smoothly displays the motion tracker data ([video](https://youtu.be/LBU31D8MB3A)). My CPU, memory, and GPU usage are **not** near maximum usage.

Is there any remedy to my issue? I know this combined task of having hundreds of models loaded while running OpenIGTLinkIF to import live motion data is demanding for slicer, but I was really hoping I could have both running simultaneously.

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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:** [July 30, 2020, 4:24pm UTC](https://discourse.slicer.org/t/3d-view-lag-when-hundreds-of-models-loaded-and-openigtlinkif-running/12792/2 "2020-07-30T16:24:01Z")

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Thanks for reporting, I don’t think there is a good reason for this to happen. @Sunderlandkyl could you check if there is an easy fix? If the fix is not trivial, then we could think about various workarounds.

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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 2, 2020, 3:18am UTC](https://discourse.slicer.org/t/3d-view-lag-when-hundreds-of-models-loaded-and-openigtlinkif-running/12792/3 "2020-08-02T03:18:58Z")

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@Sunderlandkyl has [fixed the update performance issue](https://github.com/Slicer/Slicer/pull/5075). Refresh speed should be good in Slicer Preview Release downloaded on Monday or later.

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**Author:** ![Ryan\_Morrison](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/ryan_morrison/32/7508_2.png) [@Ryan\_Morrison](https://discourse.slicer.org/u/Ryan_Morrison)\
**Post date:** [August 3, 2020, 7:40pm UTC](https://discourse.slicer.org/t/3d-view-lag-when-hundreds-of-models-loaded-and-openigtlinkif-running/12792/4 "2020-08-03T19:40:16Z")

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Thanks @lassoan and @Sunderlandkyl! I’ll give that a shot and see if it fixes the problem.

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**Author:** ![Ryan\_Morrison](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/ryan_morrison/32/7508_2.png) [@Ryan\_Morrison](https://discourse.slicer.org/u/Ryan_Morrison)\
**Post date:** [August 4, 2020, 2:27am UTC](https://discourse.slicer.org/t/3d-view-lag-when-hundreds-of-models-loaded-and-openigtlinkif-running/12792/5 "2020-08-04T02:27:03Z")

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So it’s still an issue even after updating the preview release version 4.11.0 revision 29250 built 2020-08-03. It may be because the .obj and .stl files have a large file sizes due to the files being modeled after a full sized adult male. Here is the link to the [google drive with all the files](https://drive.google.com/drive/folders/1mjIl521pzQ4rwyhzpkNtsCfRC-wnLe3R?usp=sharing). Even viewing all of the files in the 3D view is shows a lag.