A few ideas about physics vs 3d

[HornetMaX]

[Thx to whoever created this section !]

Hi all,
recently I was wondering about the rider positioning stuff and after thinking about what is in point 1 below, I went a bit further with what is in point 2.
Mostly it is something for Piboso to think about.

1. Split rider position from bike physics
As we have different bike mods on the same physics, today the rider is badly positioned most of the times.
Would it be possible to have rider positioning stuff (in the .geom file, rider, footpeg_lef/right, grip_leftpos/dir, grip_rightpos/dir and maybe even t-cam) in a separate file ?
This would allow different bikes to share the same physics but have the rider correctly positioned.

I know it's a minor abuse (cause the rider position influences the CoG and inertia tensor) but doesn't seem to be absoutely critical: I mean you could still compute them properly, but then allow bikes with different rider position to be considered as "same physics".

2. A step further
It is my understanding that today, when you create a new bike you have two possibilities:

• Use the 990 physics (for example), in which case you have to "stretch" the 3d model of the new bike to fit (as much as possible) the one of the 990
• Use your own physics, in which case you can create a true 3d model of your bike, but then you'll have to reflect the bike's geometry in the .geom file

If the above is wrong/incomplete, we can probably trash the rest of this post
Assuming it's OK, then here's the thing: it is clear that option 2 is the one closer to reality. However, option 1 has some interest IMO too: you could have visually different bikes (that's nice) using the same physics (so same bike performance). Also, you don't have to mess with the physics (and it's fairly long validation). Problem is, option 1 has that deformed bike ... bad ! So I was wondering if we could have something that allows us to have visually different bikes using the exact same physics.

I'm not 100% sure it is possible (that's where Piboso can shed light), but here's the idea.

For simplicity, let's imagine we want to create a bike that is identical to the murasama, but with a longer swingarm. We want the difference to be visual only: the bike behavior (physics) has to be the same. Today, the position of the rear wheel on the swingarm (which more or less define the swingarm length) is a parameter of the .geom file: if we change it to have the visual effevct we want, then we also change the bike's physics.
Let's say (values are not real ones) that the murasama rear wheel is positioned between min/max (0.0, 0.0, -0.5) - (0.0, 0.0, -0.6) while we want our new bike (the sukuzi ?) with the rear wheel between min/max (0.0, 0.0, -0.6) - (0.0, 0.0, -0.7).
The idea would then be to have 2 sets of parameters: one for the physics and one for the "assembling" of the 3d model. So the physics set would be identical as the 990 (i.e. (0.0, 0.0, -0.5) - (0.0, 0.0, -0.6)) while the "3d" set would be as we want (i.e. (0.0, 0.0, -0.6) - (0.0, 0.0, -0.7)).

This means that the bike will behave just like the murasama, but it will be rendered differently (as we want). The difference is purely visual, nothing else.
GPB would have to "map" the state of the bike physics (e.g. rear wheel at -0.55) to the corresponding value in the 3d world (i.e -0.65 in our example).
Notice that the gap between min/max does not have to be identical (0.10 here): it's just a linear map.

Just to give a simpler exmaple, imagine we want a bike that is just like the murasama, but 2 times bigger (scale X, Y and Z direction x2) and we want it to have the exact same physics.
This is trivially doable (when you render, render "twice as big"). Doing what I suggest is a bit more complex, but no too much.

I'm under the impression that this could be done for all the parameters that describe the bike's geometry today and that, at the same time, dictate the 3d assembly (so essentially all the purely geometrical parameters: no masses, CoG positions etc).

Notice that there's at least another parameter that has this double role (phjysics + 3d stuff): it's the wheel+tire radius, in the .tyre files (*).

Again, I'm not 100% sure it is doable, but if it is the case it could be interesting.

MaX.

(*)
You can make a funny test: take the murasama folder and edit the .tire file (quali front, for example), changing the radius to something much bigger (e.g 0.295--> 0.600) or smaller (-> 0.100), the go on track (select the right tire, of course) and see what happens

[C21]

For those who do not know:
CoG -> Center of Gravity 

Just a few words:
1. Split rider....

As we have different bike mods on the same physics, today the rider is badly positioned most of the times.

The rider is (besides the scooter mod) on every bike badly positioned including the stock bikes (Varese, MSM, Murusama)
In my opinion Piboso checked that the hands are correctly positioned in rider view (1st person) to get people a good feeling in this view.
He was not aware (or for him it was a minor detail) that the foot and the hole rider was positioned incorrectly (way too far in front).
Keep in mind: BETA! I think that this will (and have to) corrected in further beta releases (it is a minor problem imho and i don´t think that much of the gamers are aware of it).
As Piboso is developing a new rider model it maybe will be solved...

2. A step further
In my opinion option 1 (use 990 and stretch) is no option at all. I know we use this at this time right now but stretching leads to an bike feel "like on rails" and is unreal (i know that a pc sim is almost unreal....).
I agree that you can have one race class with different bikes and same physics to lay the focus on the player ability and not on the advantage or disadvantage of the bike (using different physics). Maybe its a good one for the MotoGP class right now.....but to be honest....i don´t like bikes looking different but behave equal.
The better way is to develop own physics (it´s a lot work but worth it). Maybe a little bit Hardcore....but to be as close to real as possible it´s the one and only way to go. GPB is the only Motorcycle Sim which deserves the calling "Sim", we should take advantage of that to devide GPB massivly from the competitors (which are way too aracade).

[Hawk]

I agree with you C21. Every bike should have it's own physics. In this situation each rider will have their favourite bike in the same class, and one rider will more than likely be able to ride one bike better than another even if the performance is slightly less on that bike he's riding. It's the same with setups: One setup that is spot-on for one rider will not suit another riders style of riding and vice versa. It would be the same with the different bikes and physics of the same class.