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 Post subject: Re: Future Pinball - Physic Overhaul
 Post Posted: Tue May 21, 2019 5:49 am 
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This is a nice experiment and for sure it will be useful to create some special fx in a table.
Thinking about using this for the ball physic is too complicated for everyone (even if automated) and not the real problem.

Let's say one important thing:

A skidding ball that falls in the slingshot lane touching the rubber of the slingshot will bounce in a random vector, normally to the side of the table.
A rolling ball that falls in the same lane touching the same point of the rubber will not bounce so far but would have a side bouncing creating a lot of micro fast bouncing between the 2 rubbers of the lane and loosing almost the entire speed and forces, so the ball should enter the lane almost stopped , the gravity will do the rest.


OK that's was only an example, but this shows why I don't think that is a visual problem, we should not cover the problem cause the problem remains under that cover.


Last edited by monnezzas on Tue May 21, 2019 8:24 am, edited 1 time in total.

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 Post subject: Re: Future Pinball - Physic Overhaul
 Post Posted: Tue May 21, 2019 7:10 am 
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Location: Ontario, Canada
GeorgeH wrote:
Gimli,
I personally don't use custom balls that much any more so fake ball spin doesn't really do much for me because I can't see the ball spin anyway. ...But it is pretty cool the way you made it work though.
George


This is what made me delete my thread on this. I tend to use a Standard Silver ball most of the time and don't notice the lack of spin at times...but it is glaringly obvious on textured balls, which I do think are amazing and definitely have their role.

monnezzas wrote:
This is a nice experiment and for sure it will be useful to create some special fx in a table.
Thinking about using this for the ball physic is too complicated for everyone (even if automated) and not the real problem.

It is not complicated at all just a ball toy placed at a predetermined spot and a code segment that is simply copy and pasted. And this does not effect the physics, it just corrects a visual artifact of a non-rolling ball

monnezzas wrote:
Let's say one important thing:

A skidding ball....
OK that's was only an example, but this shows why I don't think that is a visual problem, we should not cover the problem cause the problem remains under that cover.


You may be onto something....Temporarily counterbalanced spin through"Skidding" or "Sliding" vs Exceeding the Pinball Simulation Limits (Artifact)

1. Artifact Theory - The ball should be visually spinning but isn't.
Why ? There are so many parameters in Newton Physics Engine to simulate objects in motion. And it is only a narrow band that is applicable to a ball, let alone a pinball that we expect to behave in certain way.

When the physics strays beyond the boundaries of our pinball expectations, then other things occur. And in our case the spherical ball starts behaving like a "cube" according to Monnezzas (but I believe he is observing "Skidding' see below) or a "hockey puck" which is my perception and supported by understanding "damping"

Angular Damping
there are two types of damping Linear and Angular according to this site:
https://docs.unrealengine.com/en-us/Eng ... AndDamping

Linear damping is like putting on the breaks to linear movement

Angular Damping slows or stops rotation (spin)

The Damping in physics tweaks /the FP xml is Angular Damping

My observation is that if you increase Angular Damping to 10. The ball behaves like a puck
(no longer a Pinball) and is very predictable as all spin has been removed.

Removing angular damping gives a crazy rotation and ball behaves like a ping pong ball.
(No longer a Pinball)

2. Temporarily Counterbalanced Spin ("Skid" /"Slide")
It may be possible that what Monnezzas is seeing when he describes weird behavior to non spinning ball are during times of Skid or Slide.

Skid - Is like a car putting on the brakes....picture a ball rolling up the table ...it should have a rolling rotation at a certain speed.

If this is perfectly offset by backspin then the ball will skid up the table and you will see no rotation....until these offsetting factors no longer match (ie back spin force dissipates,
or a different surface with different friction like a ramp is hit)

The visual appearance of no rotation in a Skidding ball....must be a rare occurrence
because it involves perfect offsetting of all axes of rotation..which would be next to impossible in a ball spinning along multiple axes at the same time.

Monnezzas has observed this in plunger lanes and slingshot lanes...so I suppose that is possible as the ball is being constrained by the lane guide wires and rubbers


Slide - Is like a car hitting a patch of oil on the road. Occurs when the frictional force suddenly lessens.

Again this can lead to a non-spinning situation if a previously stopped ball fails to rotate as it falls if no rotational forces have been applied and no frictional force are resisting.

A non-spinning sliding ball probably will behave more predictably than a skidding ball as it has no rotational forces. The skidding ball still contains all of its desire to spin and when
hit it will unleash these unseen dynamics as its forces are no longer being concealed by offsetting forces.

Conclusion:

There a two glaring problems that FP has been charge with:

1. Poor Flipper Aiming - thanks to Rav's dynamic flipper coding we can now dramatically improve this.

2. Wildly unpredictable ball collisions. We can dramatically improve this by increasing angular damping.

Problems:

We can end up with a too predicable table that always responds how we predict and therefore doesn't seem real.

This is fabulous problem to have ! From there all we need to do is slightly loosen our parameters or include a tiny measure of randomness in the code.

If constraining angular rotation leads to the artifact described above, we can deal with that
as described previously.

The true significance of "Skidding" as a real problem remains to be seen


Last edited by Gimli on Fri Jun 21, 2019 11:08 pm, edited 1 time in total.

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 Post subject: Re: Future Pinball - Physic Overhaul
 Post Posted: Tue May 21, 2019 12:10 pm 
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Location: Arkansas, USA
Gimli wrote:
We can end up with a too predicable table that always responds how we predict and therefore doesn't seem real.


Some of the parameters have randomness that can be adjusted so there is some control over this.

Gimli wrote:
The true significance of "Skidding" as a real problem remains to be seen


I have never identified it as a problem myself. That is why I am interested in what Monnezzas has been doing on it. Sometimes you don't notice you have a problem until it is fixed.

I can say I usually don't like tables that have a slope less than 6 or more than 8.

George


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 Post subject: Re: Future Pinball - Physic Overhaul
 Post Posted: Tue May 21, 2019 12:59 pm 
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Ok I need to make a slow motion video to explain better, but at the moment I'm not at home.

At the moment I can say that the only differences in the physic between Fp standard/zed/2.5/2.6/2.7 and my tables (Abra, Buccaneer, Medieval Madness ) is in substance only that the ball always rolls. If I would had leaved the ball sliding I'm sure that no one could notice any difference from standard fp physic.

Yes I've even changed the gravity and the usual slope of these tables, but all changed parameters pointed to make the ball spins and roll always.

Check what happen when you bang a rolling ball with the flippers or when the ball slide.in the first case the ball is a bullet, just like in real pinball machines


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 Post subject: Re: Future Pinball - Physic Overhaul
 Post Posted: Tue May 21, 2019 4:39 pm 
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GeorgeH wrote:
...
I can say I usually don't like tables that have a slope less than 6 or more than 8.

George


In my tables my usual slope goes from 2,8 to max 4,2 but the gravity and ball mass are increased so the speed is like a 5 to 7 slope


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 Post subject: Re: Future Pinball - Physic Overhaul
 Post Posted: Wed May 22, 2019 11:49 am 
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Location: Arkansas, USA
blue wrote:
Alternate gate mass.

Code:
'  <gate mass=".1" gravity="500.0" damping=".25"></gate>




I tried these values on ID4 but couldn't use them. The ball would go up the ramp, hit the gate and roll back down. I ended up having to use these values:

' <gate mass="0.010" gravity="100" damping="0.25"></gate>

George


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 Post subject: Re: Future Pinball - Physic Overhaul
 Post Posted: Wed May 22, 2019 3:23 pm 
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Joined: Tue May 01, 2012 11:13 pm
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Location: Abbotsford
Interesting, has to be something with the collision then. This may be something we just can not fix, Maybe instead just use a dropable wall instead of a gate, thats what I always end up doing.

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 Post subject: Re: Future Pinball - Physic Overhaul
 Post Posted: Wed May 22, 2019 4:49 pm 
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Joined: Thu Aug 16, 2012 11:12 pm
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Location: Arkansas, USA
ID4 is pretty unique. Two of the ramps have 3 gates and one of them has 2 gates.

George


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 Post subject: Re: Future Pinball - Physic Overhaul
 Post Posted: Thu May 23, 2019 2:26 am 
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You can consider toy (and rotate it with .Rotate) and invisible triggers.

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 Post subject: Re: Future Pinball - Physic Overhaul
 Post Posted: Thu May 23, 2019 7:01 am 
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Popotte wrote:
You can consider toy (and rotate it with .Rotate) and invisible triggers.


I am basically finished with the table but are you saying to convert the gate to a toy and replace the trigger with an invisible one?

George


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