# SlicerRT built from source cannot start

**URL:** <https://discourse.slicer.org/t/slicerrt-built-from-source-cannot-start/43792>\
**Category:** Support\
**Tags:** build\
**Created:** [July 21, 2025, 8:52am UTC](https://discourse.slicer.org/t/slicerrt-built-from-source-cannot-start/43792 "2025-07-21T08:52:11Z")\
**Posts on this page:** 1\
**Showing post:** 6

<div class="post-metadata">

**Author:** ![chir.set](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/chir.set/32/66982_2.png) [@chir.set](https://discourse.slicer.org/u/chir.set)\
**Post date:** [July 21, 2025, 4:51pm UTC](https://discourse.slicer.org/t/slicerrt-built-from-source-cannot-start/43792/6 "2025-07-21T16:51:40Z")

</div>

> [@ferhue](#):
>
> ` 1594 | polygon->Triangulate(polygonIds);`

You could try:

> polygon-\>NonDegenerateTriangulate(polygonIds);

It seems VTK 9.5 has made this incompatible change.

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