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 Post subject: how to prevent the tunnel effect?
 Post Posted: Tue May 21, 2019 8:48 am 
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Joined: Sun Dec 30, 2018 8:17 am
Posts: 68
Location: France
when a ball has too much energy, it goes through the polygons.
how to prevent the tunnel effect?


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 Post subject: Re: how to prevent the tunnel effect?
 Post Posted: Tue May 21, 2019 11:51 am 
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Joined: Thu Aug 16, 2012 11:12 pm
Posts: 2161
Location: Arkansas, USA
I think you are saying that you are having problems with the ball going through your models. It is usually a physics problem unless of course your models are not collidable. Try reducing ball mass and/or ball gravity in the XML.

George


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 Post subject: Re: how to prevent the tunnel effect?
 Post Posted: Tue May 21, 2019 12:36 pm 
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Joined: Sun Dec 30, 2018 8:17 am
Posts: 68
Location: France
no George

where this happens (very rarely), there are no toys. only a guide, a rubber and lane guide but next to a bumper (à coté d'un bumper) !!!!! and a surface (pf) above....
I have explored the table, I do not see any passage or the ball could possibly passed.... :?: :!:

can the thickness of the guide affect? it is in my case at 1 mm
est-ce que l'épaisseur du guide peut influer ? il est dans mon cas à 1 mm


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 Post subject: Re: how to prevent the tunnel effect?
 Post Posted: Tue May 21, 2019 12:39 pm 
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Joined: Mon Jan 27, 2014 12:36 pm
Posts: 2612
Location: Ontario, Canada
Rav explained this somewhere...has to do with speed settings I think...


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 Post subject: Re: how to prevent the tunnel effect?
 Post Posted: Tue May 21, 2019 12:50 pm 
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Joined: Mon Jan 27, 2014 12:36 pm
Posts: 2612
Location: Ontario, Canada
Rav wrote:
What that values means?
Ball can traver up to 2700 mm in 1 second. So, if i split it by physics sim FPS i get: 2700 / 256 = ~10.5 mm between 2 physics frames.
For normal play it will be: 1800 / 256 = ~7 mm
Ball diameter is 27 mm.
Do you see where may you have problems? Gate is "thin" object. In one frame ball may not touch gate (no collision) in next frame gate may be 10 mm "inside" ball and physics engine will have to solve what to do.
You can guess, that on some tables ball may be faster.
How it looks at current "Moster bash" beta table?
- ~2200 after hit by plunger
- ~4850 after flipper hit fast moving ball (i guess ball may go faster)
And FPS in XML? Well FPS = 295
So, we have: 4850 / 295 = 16.4 mm. Over half of ball can sink into wall before collison will be detected. I guess if you have gate with metal part 17? 18? 19? mm above playfield sometimes ball can fly under gate without hit detection.
Evene if gate will be hit, ball center may be already at other side of gate and physics engine may decide to spin gate in oposite direction.

This is realy fast ball... almost 5 m/s .... or ... 18 km/h .... or ... 11 mph ... well maybe not that fast :)
Any way.... my advise: limit ball speed hited by flippers or increase FPS.


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 Post subject: Re: how to prevent the tunnel effect?
 Post Posted: Tue May 21, 2019 1:25 pm 
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Joined: Thu Aug 16, 2012 11:12 pm
Posts: 2161
Location: Arkansas, USA
I remember reading that although I never really understood it. ...But Rav's fix is to either lower flipper omega or raise FPS. I don't recommend raising FPS above 296 because the guys with lower end PCs will complain about low frame rate (or stuttering). Lowering flipper omega is a possible fix. Lowering ball speed can also be accomplished by reducing ball mass and/or ball gravity so it might help. You might try Malifica's XML file that is available here:

viewtopic.php?f=86&t=6173

If you are using dynamic flippers, you should try using the values for omega that I suggest in the comments in the script of one of the tables I have posted.

George


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 Post subject: Re: how to prevent the tunnel effect?
 Post Posted: Tue May 21, 2019 1:39 pm 
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Joined: Sun Dec 30, 2018 8:17 am
Posts: 68
Location: France
my problem is not a flipper, but a bumper.
I have however reduced its strength to 3, below it is unimaginable (on a real pinball, the force is very important), so will increase the thickness of the guide (at 3 mm).
will inform you of the result.

lit would be interesting to have a conversion table between the values of a real pinball and the value of FP.


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 Post subject: Re: how to prevent the tunnel effect?
 Post Posted: Tue May 21, 2019 4:15 pm 
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Joined: Thu Aug 16, 2012 11:12 pm
Posts: 2161
Location: Arkansas, USA
I think you have the idea. You basically need to reduce strengths of things.

George


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