# Plus and negative side of an internal facet

**URL:** <https://fenicsproject.discourse.group/t/plus-and-negative-side-of-an-internal-facet/14663>\
**Category:** variational formulation\
**Created:** [May 15, 2024, 1:05am UTC](https://fenicsproject.discourse.group/t/plus-and-negative-side-of-an-internal-facet/14663 "2024-05-15T01:05:23Z")\
**Posts on this page:** 1\
**Showing post:** 2

<div class="post-metadata">

**Author:** ![leshinka](https://yyz2.discourse-cdn.com/free1/user_avatar/fenicsproject.discourse.group/leshinka/32/5789_2.png) [@leshinka](https://fenicsproject.discourse.group/u/leshinka)\
**Post date:** [May 15, 2024, 2:43am UTC](https://fenicsproject.discourse.group/t/plus-and-negative-side-of-an-internal-facet/14663/2 "2024-05-15T02:43:42Z")

</div>

Further investigation shows that it is related to [Facets orientation in inner surface with fenicsX - #3 by RaphaelC](https://fenicsproject.discourse.group/t/facets-orientation-in-inner-surface-with-fenicsx/8034/3), but I cannot figure out what the solution is. At the interface between the subdomains, the orientation needs to be definite. For example, I may want the turquoise domain to be “+” and the pink domain to be “-”.

---

_[View the full topic](https://fenicsproject.discourse.group/t/plus-and-negative-side-of-an-internal-facet/14663)._