# Step-by-Step Tutorial Session 3 - Yaw Angle Study (Part 2)
**URL:** https://www.simscale.com/forum/t/step-by-step-tutorial-session-3-yaw-angle-study-part-2/79720
**Category:** Formula Student/SAE Workshop - 2017
**Created:** [September 12, 2017, 6:47am UTC](https://www.simscale.com/forum/t/step-by-step-tutorial-session-3-yaw-angle-study-part-2/79720 "2017-09-12T06:47:30Z")
**Posts on this page:** 5
**Page:** 4
### Author:  [@ricardo\_3282](https://www.simscale.com/forum/u/ricardo_3282)
#### Post date: [June 24, 2018, 7:58pm UTC](https://www.simscale.com/forum/t/step-by-step-tutorial-session-3-yaw-angle-study-part-2/79720/65 "2018-06-24T19:58:06Z")
Hi @vgon_alves, sorry about that.
I fixed and ran the simulation again, but it still fails after 31 minutes.
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### Author:  [@Get\_Barried](https://www.simscale.com/forum/u/Get_Barried)
#### Post date: [June 25, 2018, 6:39am UTC](https://www.simscale.com/forum/t/step-by-step-tutorial-session-3-yaw-angle-study-part-2/79720/66 "2018-06-25T06:39:09Z")
Hi everyone,
@jousefm Same issue indeed with the other user. Issue with the CAD model? The meshing isn’t being very cooperative.
@ricardo_3282 the issue lies with the illegal cell count as you can see below. Anything over around a 100 or so illegal cells is sure to at the very least make your simulation unstable. As I’ve mentioned earlier, another user had the same issue but it has proven rather tricky to get the count down low enough. Will get back to you when a solution is found.
Cheers.
Regards,
Barry
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### Author:  [@jousefm](https://www.simscale.com/forum/u/jousefm)
#### Post date: [June 25, 2018, 8:08am UTC](https://www.simscale.com/forum/t/step-by-step-tutorial-session-3-yaw-angle-study-part-2/79720/67 "2018-06-25T08:08:01Z")
Hi @Get_Barried!
I do not think that this is necessarily related to the CAD but rather to the mesher - but that’s something I would have to confirm first and really make sure it is not the CAD.
Keeping you guys up-to-date!
Jousef
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### Author:  [@yosukegb4](https://www.simscale.com/forum/u/yosukegb4)
#### Post date: [June 27, 2018, 7:00am UTC](https://www.simscale.com/forum/t/step-by-step-tutorial-session-3-yaw-angle-study-part-2/79720/68 "2018-06-27T07:00:46Z")
Hi everyone!
In my experience, this kind of error occured when some much different boundary conditions touched each other.
The cause of those wrong conditions often existed between a wheel and a hub/upright system.
In @ricardo_3282 's simulation, I found some much different boundary conditions seem to touch each other as shown below.
- between the front and rear hubs and wheels
- between the front and rear wheels and the floor
So I make 2 proposals as below for now.
1. Correct the boundary conditions of the faces between the wheels and the floor
2. Make spaces around 20mm between the hubs and the wheels
How about trying them? @ricardo_3282
Best,
Yosuke
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### Author:  [@ricardo\_3282](https://www.simscale.com/forum/u/ricardo_3282)
#### Post date: [June 29, 2018, 4:40am UTC](https://www.simscale.com/forum/t/step-by-step-tutorial-session-3-yaw-angle-study-part-2/79720/69 "2018-06-29T04:40:54Z")
Hi @yosukegb4, I’ll try them, thank you very much.
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