Improved Social Distancing and NPC behaviour

[ghost]

Overview

Right now, social distancing is almost binary: Either, every contact leads to infection, or no contact does.

Instead, when social distancing is high, NPCs should actively work to keep their distance, but should still be allowed to touch (e.g. in overcrowded areas). This can be implemented by a kind of 'comfort zone'. If another human comes into an NPC's comfort zone, it should attempt to move away from it.

Also, NPC's infection radius should be smaller when social distancing is higher, simulating less contact with people close by.

NPC Behaviour

• There will be a global Social Distancing Modifier implemented in LevelSettings, and a unique social distancing modifier for each NPC which deviates from the global by a few percent.
• Go Out and Go Home will be decided randomly every N seconds, with the social distancing modifier as a bias

Parameters

In the DefaultNPC prefab, a few parameters can be changed to influence these behaviours:

NPC Script

• MinVelocity and MaxVelocity define the NPC's velocity depending on social distancing. The NPCs actual velocity is lineary interpolated between Min and Max, depending on the social distancing factor.
• KeepBehaviourForSeconds is the time interval for checking for behaviour changes: After this many seconds, the NPC's behaviour will be reevaluated.

Comfort Zone Script:

• MinRadius and MaxRadius: Depending on the social distancing factor, the ComfortZone's actual radius is lineary interpolated between these two.
• Sensitivity: A measure for how quickly the NPC reacts to other humans in its comfort zone.

Checklist

• [x] Comfort zone: NPCs try to move away from other humans when they come too close
• [x] Adaptive velocity: Higher social distancing means slower movement
• [ ] Stay-at-home: All NPCs should alternate between staying at home and going out. The higher the social distancing factor, the less they should leave the house.
• [ ] Staying at home with symptoms: As soon as an NPC gets ill (red smiley), it should stay at home most of the time.

[maccxs]

I would like the "moving away from each other" stuff. I will keep working on improving the SEIR model, where not every contact leads to an infection... you can already have a first look at it in the resepective branch. If you watch the SEIR Game-Object during play, you see the SEIR mdoel predictions compared to the visualization by the SMILEYS (which is not one to one due to their randomness).

[holke]

When social distancing is high, some NPCs should stop moving at all, because they „stay at home“. This feels much more like the real world social distancing.

[maccxs]

Maybe then put a little house around the smiley where he is safe.

[maccxs]

Like this one https://pixabay.com/vectors/building-house-home-real-estate-295207/, no door, instead smiley inside

[ghost]

I like that idea :) NPC's that stay at home can't be infected. I think NPCs should alternate between staying at home and moving outside during the game, but the higher social distancing is, the less they should leave the house. Also, maybe sick NPC's (red smiley) should stay at home most of the time.

How about we fix the starting position of an NPC as their home, and have them return there regulary?

[ghost]

I'm implementing the behaviour graph I added above. Any comments / opinions? For now, I'll make it so that an NPC just 'builds their home' wherever they are at the moment.

[ghost]

Since NPC behavior becomes more and more complicated with this issue and #61 , I recommend we use the GitHub Wiki to keep track of all the components, their interactions and the way they control the NPC's behaviour.

[maccxs]

I like the behaviour graph. I would say that the NPCs do not run away if someone is in their comfort zone but rather walk around / make space. / stay to the side as we would do in the real world! The NPCs could first simply build a house where they are, I agree. GitHUb Wiki, yes!

[maccxs]

What I would like for my infection model: Knoledge about how long one human was "near" another one. Which I would like to have influence on the spread. So if you see a way to integrate this easily, I would be happy.

[maccxs]

The red smileys have symptoms but the should not necessarily stay home, rather stay home more. Beccause not everyone with symptom is really very sick. Only a fraction of them, so make this variable.

[ghost]

@maccxs Check out the playground scene I made for testing the comfort zone. (Branch frederik/advancedSocialDistancing). Enter play mode and move the NPCs around in the scene view. Then you can see green lines between NPCs who are in each other's comfort zone, and red lines which show the calculated escape directions.

Right now, I'm finding the direction that leads as far away from all NPCs in the zone. Since in RandomMovement mode, NPCs do not have a target they want to get to, I think just trying to get away is fine. If there is a target (like a supermarket, home, ...), we can add the direction to the target into the calculation, making the NPC move around others.

[maccxs]

That sounds fine. I will have a look at that branch this evening or tomorrow.

[ghost]

What I would like for my infection model: Knoledge about how long one human was "near" another one. Which I would like to have influence on the spread. So if you see a way to integrate this easily, I would be happy.

That's easy. I'll give you an event in the comfort zone script you can subscribe to from your infection model like this:

// Assuming npc is an NPC
ComfortZone zone = npc.GetComponentInChildren<ComfortZone>();
zone.HumanEntered += HumanEnteredHandler;
zone.HumanLeft += HumanLeftHandler;

with

class ComfortZoneChangeArgs : EventArgs {
    public float timestamp;
    public NPC comfortZoneOwner;
    public HumanBase other;
}

You have to define

private void HumanEnteredHandler(object sender, ComfortZoneChangeArgs args) { ... }
private void HumanLeftHandler(object sender, ComfortZoneChangeArgs args) { ... }

These methods will then be called whenever another Human enters or leaves someone's comfort zone. From the args structure you can then build your statistics ;)

[ghost]

You are invited to play around with the parameters which control the behaviour and find the settings which feel most natural. I listed them all in the issue description.

[maccxs]

Ok, I will. Thanks!

[maccxs]

I tried it out and I do not really have any big change requests. Maybe just some small comments:

• Make sure that this still looks natural if ALL the smileys are allowed to move which is the hard case with 100% social distancing
• For my taste, too many smileys stay at home. We should only allow a more limited number of them to stay at home at least on our small map (and of course, they won't get infected anymore).
• Maybe for every 5% social distancing 1 smiley (at the same time)
• Good job! I know this is really not easy to do! I played with this around a lot myself when I implented the social distancing and it never looked natural (e.g. when I made the smileys move away, etc.)

[ghost]

By the way, I guess you have noticed that I've been inactive the past week. The summer semester has started and demands its toll. I hope I can catch up and get something done again next weekend :)

[maccxs]

Hi @FredyHennig: Good to hear from you. Your studies, of course, are much more important than contributing here. That is perfectly fine. We were just a little worried since we did not hear from you. We decided to tackle the next relase with 3 levels that are described in the issues and one already existing party level. For these, we are not dependent on the new behaviour of the NPCs yet (which is a bonus, of course). I think, it is good to take baby steps here and not want to much at once. So, just work on it when you have time :-)