# What is the placement of curve IfcLinearPlacement.PlacementMeasuredAlong

**URL:** <https://forums.buildingsmart.org/t/what-is-the-placement-of-curve-ifclinearplacement-placementmeasuredalong/2822>\
**Category:** Developers\
**Tags:** 4x3alpha\
**Created:** [July 2, 2020, 6:47am UTC](https://forums.buildingsmart.org/t/what-is-the-placement-of-curve-ifclinearplacement-placementmeasuredalong/2822 "2020-07-02T06:47:58Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![igor.sokolov](https://sea2.discourse-cdn.com/flex016/user_avatar/forums.buildingsmart.org/igor.sokolov/32/25_2.png) [@igor.sokolov](https://forums.buildingsmart.org/u/igor.sokolov)\
**Post date:** [July 2, 2020, 6:47am UTC](https://forums.buildingsmart.org/t/what-is-the-placement-of-curve-ifclinearplacement-placementmeasuredalong/2822/1 "2020-07-02T06:47:58Z")

</div>

IfcLinearPlacement.PlacementMeasuredAlong references to curve, but what coordinate system is used for the curve?

I have to search IfcProduct that has the curve in Representations and use ObjectPlacement to have answer.

If this is curve referenced by IfcAlignment.Axis - I possible have to use its ObjectPlacemenyt but see no specification for this at all.

---

<div class="post-metadata">

**Author:** ![Moult](https://sea2.discourse-cdn.com/flex016/user_avatar/forums.buildingsmart.org/moult/32/196_2.png) [@Moult](https://forums.buildingsmart.org/u/Moult)\
**Post date:** [June 8, 2021, 4:01am UTC](https://forums.buildingsmart.org/t/what-is-the-placement-of-curve-ifclinearplacement-placementmeasuredalong/2822/2 "2021-06-08T04:01:38Z")

</div>

This thread is now resolved as per: [What is the placement of curve IfcLinearPlacement.PlacementMeasuredAlong · Issue #2 · buildingSMART/IFC4.3.x-development · GitHub](https://github.com/buildingSMART/IFC4.3.x-development/issues/2)