# Need Help Making Ambiguous Shapes Illusion

**URL:** <https://discourse.shapr3d.com/t/need-help-making-ambiguous-shapes-illusion/26402>\
**Category:** Modeling Questions\
**Created:** [June 21, 2023, 6:55am UTC](https://discourse.shapr3d.com/t/need-help-making-ambiguous-shapes-illusion/26402 "2023-06-21T06:55:57Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![xtagon](https://avatars.discourse-cdn.com/v4/letter/x/c37758/32.png) [@xtagon](https://discourse.shapr3d.com/u/xtagon)\
**Post date:** [June 21, 2023, 6:55am UTC](https://discourse.shapr3d.com/t/need-help-making-ambiguous-shapes-illusion/26402/1 "2023-06-21T06:55:57Z")

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I’m attempting to learn how to use Shapr3D to design custom “ambiguous shape” illusions in the style of Kokichi Sugihara.

Before I do any custom ones, I just want to make sure I know what tools to use to do a basic one, so I’m following this tutorial which is meant for Fusion360 and my hope is to translate the technique to Shapr3D’s capabilities.

[![](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/5/0/50ace40449babf79ad9714b72a8dbc473c8496c3.jpeg "How to Make Ambiguous Shapes // Fusion 360 Tutorial") ](https://www.youtube.com/watch?v=WSlk5kbdFME)

Using Shapr3D instead of Fusion360, I was able to follow along up until about the 8:30 mark here: [How to Make Ambiguous Shapes // Fusion 360 Tutorial - YouTube](https://youtu.be/WSlk5kbdFME?t=516)

Sketching the circle and triangle outlines was no problem, sketching the lines coming down at an angle was no problem, and the sweep tool worked, but what tool should I use to get that curve?

I tried performing an intersection, and that produced a body with which the curve I want could be selected, but there doesn’t seem to be any way that I know of to remove the solid body and extract/project just the curve so that it could be joined with the inner part and extruded downward. If I select the curve and project it, it projects onto a flat sketch, but this is not what I want–the curve has 3 dimensions to it, and the height is really what makes the illusion work.

Any help would be appreciated! I’m starting to think it’s not possible 😮