# Intersect and subtract of 2 overlapped ExtrudePolygon
**URL:** https://forum.babylonjs.com/t/intersect-and-subtract-of-2-overlapped-extrudepolygon/13801
**Category:** Questions
**Created:** [August 31, 2020, 6:46am UTC](https://forum.babylonjs.com/t/intersect-and-subtract-of-2-overlapped-extrudepolygon/13801 "2020-08-31T06:46:51Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@neofita](https://forum.babylonjs.com/u/neofita)
#### Post date: [August 31, 2020, 6:46am UTC](https://forum.babylonjs.com/t/intersect-and-subtract-of-2-overlapped-extrudepolygon/13801/1 "2020-08-31T06:46:51Z")
Hello evryone,
i have a problem aboout 2 overlapped ExtrudedPolygon when i interset or subtract with another ExtrudeShapeCustom
I know from another post that in some case for ExtrudedPolygon is necessary to do the inverse of array but i don t know why so i ve tried different solutions
There are these 3 PG for report my problem:
- the first without inverse of the arrays that creates the ExtrudedPolygons
[Babylon.js Playground](https://playground.babylonjs.com/#EUCIKC)
- the second with inverse of both arrays that creates the ExtrudedPolygons
[https://playground.babylonjs.com/#EUCIKC#1](https://playground.babylonjs.com/#EUCIKC#1)
- the thirth with inverse of one array and the other no. This example looks near the solution but not at alla and especially i don’ t know why in some case i have to inverse and in other cases no
[https://playground.babylonjs.com/#EUCIKC#2](https://playground.babylonjs.com/#EUCIKC#2)
Thank you in adcance
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### Author:  [@Evgeni\_Popov](https://forum.babylonjs.com/u/Evgeni_Popov)
#### Post date: [August 31, 2020, 9:49am UTC](https://forum.babylonjs.com/t/intersect-and-subtract-of-2-overlapped-extrudepolygon/13801/2 "2020-08-31T09:49:33Z")
Maybe someone can help you on that matter (I know @JohnK is a master of parametric shapes) but in any case you should really try to show up your problem with smaller PGs because such big PGs could discourage some people.
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### Author:  [@JohnK](https://forum.babylonjs.com/u/JohnK)
#### Post date: [August 31, 2020, 9:58am UTC](https://forum.babylonjs.com/t/intersect-and-subtract-of-2-overlapped-extrudepolygon/13801/3 "2020-08-31T09:58:59Z")
> [@neofita](#):
>
> i don’ t know why in some case i have to inverse and in other cases no
From [https://doc.babylonjs.com/how\_to/parametric\_shapes#extruded-non-regular-polygon](https://doc.babylonjs.com/how_to/parametric_shapes#extruded-non-regular-polygon) see
_All vectors for shape and holes are Vector3 and should be in the XoZ plane, ie of the form BABYLON.Vector3(x, 0, z) and in counter clockwise order._
If your array happens to be in clockwise order reversing it puts it in counter clockwise order.
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### Author:  [@neofita](https://forum.babylonjs.com/u/neofita)
#### Post date: [September 2, 2020, 8:29am UTC](https://forum.babylonjs.com/t/intersect-and-subtract-of-2-overlapped-extrudepolygon/13801/4 "2020-09-02T08:29:46Z")
I’ ve simplified all in this task
> [@Intersect and subtract of 2 overlapped ExtrudePolygon - #2](https://forum.babylonjs.com/t/intersect-and-subtract-of-2-overlapped-extrudepolygon-2/13846):
>
> Hello everyone, i have a problem aboout 2 overlapped ExtrudedPolygon when i interset or subtract with another ExtrudeShapeCustom I dont understand why the wrench is cutted and why it appear deepest than the quare [https://playground.babylonjs.com/#LFWQQK](https://playground.babylonjs.com/#LFWQQK) Thank you in advance
Thank you