# Cannot extrude a projected sketch
**URL:** https://discourse.shapr3d.com/t/cannot-extrude-a-projected-sketch/35747
**Category:** Modeling Questions
**Created:** [December 24, 2024, 11:04pm UTC](https://discourse.shapr3d.com/t/cannot-extrude-a-projected-sketch/35747 "2024-12-24T23:04:35Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@pali](https://discourse.shapr3d.com/u/pali)
#### Post date: [December 24, 2024, 11:04pm UTC](https://discourse.shapr3d.com/t/cannot-extrude-a-projected-sketch/35747/1 "2024-12-24T23:04:35Z")
Hey guys,
I am facing an issue - it seems it has been raised already, but I couldn’t find a proper answer for me: [Can’t extrude a sketch that was projected - History-Based Parametric Modeling Beta - Shapr3D Community](https://discourse.shapr3d.com/t/can-t-extrude-a-sketch-that-was-projected/28094)
So the thing is: I have a ball (which should be a nose) and projected two sketches on it (which shall be nostrils). I now want to extrude these projections to get a projection equally deep on the curved surface. I already did this a few times and it worked great, but this time the error “Operation failed because the resulting body wouldn’t be valid”. The preview of the action looks great though… Any thoughts?
Thanks and best regards,
Patrick
---
### Author:  [@SCALEMODEL](https://discourse.shapr3d.com/u/SCALEMODEL)
#### Post date: [December 24, 2024, 11:45pm UTC](https://discourse.shapr3d.com/t/cannot-extrude-a-projected-sketch/35747/2 "2024-12-24T23:45:19Z")
You might be coming to the limitations of doing it the CAD WAY!
---
### Author:  [@Oregonerd](https://discourse.shapr3d.com/u/Oregonerd)
#### Post date: [December 25, 2024, 12:45am UTC](https://discourse.shapr3d.com/t/cannot-extrude-a-projected-sketch/35747/3 "2024-12-25T00:45:33Z")
Potential workaround: Place a construction plane in front of it and project the oval to the plane. Extrude it and then use “Replace face” to meld it back to the main body.
---
### Author:  [@pali](https://discourse.shapr3d.com/u/pali)
#### Post date: [December 25, 2024, 7:24pm UTC](https://discourse.shapr3d.com/t/cannot-extrude-a-projected-sketch/35747/4 "2024-12-25T19:24:50Z")
Thanks for your reply! But that would add material wouldn‘t it? I want to remove material instead.
It is weird that it works sometimes and sometimes it does not 😕
---
### Author:  [@Oregonerd](https://discourse.shapr3d.com/u/Oregonerd)
#### Post date: [December 26, 2024, 2:12am UTC](https://discourse.shapr3d.com/t/cannot-extrude-a-projected-sketch/35747/5 "2024-12-26T02:12:24Z")
My bad didn’t read thoroughly. But still same same workaround except select make new body, replace face then subtract?
Not sure why the intermittent trouble.
---
### Author:  [@pali](https://discourse.shapr3d.com/u/pali)
#### Post date: [December 26, 2024, 7:41pm UTC](https://discourse.shapr3d.com/t/cannot-extrude-a-projected-sketch/35747/6 "2024-12-26T19:41:59Z")
Great idea, but I cannot select new body upon using the face replacement. Therefore the hole is just filled again and I cannot adjusted the heigth of it