## Collisions leads to model "exploding"

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mthor13
Posts: 44
Joined: 03 Jul 2017, 08:32
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### Collisions leads to model "exploding"

Hi everyone,

As shown in the video below, I have had a problem for some time with a set of collisions leading the model blowing up.
I am using the Vortex Dynamic Engine and CoppeliaSim v. 4.0.0 (rev. 1).

Does anyone know if this is fixable?

Best Regards,
Mathias Thor

mthor13
Posts: 44
Joined: 03 Jul 2017, 08:32
Contact:

### Re: Collisions leads to model "exploding"

So apparently all I needed to do was to post the question in here :)

In other words, I found the answer to the problem my self. If anyone else faces this issue, then try to adjust/reduce Vortex's "Contact tolerance [m]". I changed mine to 1.0000e-10 from 1.0000e-03.

Maybe this should be changed so that it per default is smaller in future CoppeliaSim versions?

Best Regards,
Mathias Thor

Never mind - the above solution only made the problem appear less frequently (so not fixed).
Last edited by mthor13 on 28 Jan 2020, 15:57, edited 1 time in total.

coppelia
Posts: 7597
Joined: 14 Dec 2012, 00:25

### Re: Collisions leads to model "exploding"

Hello Mathias,

that is strange. It seems that, for some reason, one leg is landing under the floor, and this situation can't be salvaged. What happens if you simply use a floor with a much larger thickness?

Cheers

mthor13
Posts: 44
Joined: 03 Jul 2017, 08:32
Contact:

### Re: Collisions leads to model "exploding"

Hi Coppelia,
Making the floor thicker helped and it doesn't happen as frequently any more - but it still happens.

It never happens when the hexapod is not colliding with anything else. It almost seems like it cannot handle all of the collisions.

coppelia
Posts: 7597
Joined: 14 Dec 2012, 00:25

### Re: Collisions leads to model "exploding"

From what I can see you modelled the feet with a primitive sphere (i.e. pure sphere) and the floor/obstacles are primitive cuboids? If not, make at least sure that those shapes are convex.
Also, you could try to explore the many material properties available with the Vortex engine (e.g. skin thickness?)

Cheers

mthor13
Posts: 44
Joined: 03 Jul 2017, 08:32
Contact:

### Re: Collisions leads to model "exploding"

I played a bit with the vortex engine material properties and found that my problem could be fixed by increasing the compliance of the materials :)

Best Regards,
Mathias Thor

coppelia