# ALPACA open3d error

**URL:** <https://discourse.slicer.org/t/alpaca-open3d-error/29483>\
**Category:** Support\
**Created:** [May 15, 2023, 11:57pm UTC](https://discourse.slicer.org/t/alpaca-open3d-error/29483 "2023-05-15T23:57:34Z")\
**Posts on this page:** 1\
**Showing post:** 2

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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:** [May 16, 2023, 12:33am UTC](https://discourse.slicer.org/t/alpaca-open3d-error/29483/2 "2023-05-16T00:33:02Z")

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Unfortunately open3d never worked consistently well for us, causing many different problems especially in cross-platform. We have reimplemented the functionality in open3d as part of the ITK, and a new alpaca module called alpaca\_preview is available in latest SlicerMorph. See this thread on how to enable it.

> [@Increasing ALPACA Non-Rigid Alignment](https://discourse.slicer.org/t/increasing-alpaca-non-rigid-alignment/28906/3):
>
> How many points are you left with during the pointcloud conversion? (ALPACA should report the number of points). If it is too few, that might be the problem. Try changing both alpha and beta values together. Increasing CPD iterations will probably be useful as well. Finally, the current ALPACA module will be deprecated soon, and we will switch to an ITK based implementation (instead of open3d we are currently using). Make sure you start using, it is already available with SlicerMorph (it is …

Going forward, this ITK based ALPACA will be default and we will stop using open3d. Our test how shown that ITK based implementation is in fact gives us slightly better results.

I suggest you start using the ITK-ALPACA (alpaca\_preview) as well.

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_[View the full topic](https://discourse.slicer.org/t/alpaca-open3d-error/29483)._