NetCode: How to set child component handling?

Hi all,

I have a prefab that has a hierarchical structure. On some of the children, I have Unity.Physics-related authoring components. Currently, these components are also sent to the clients.

However, I'd like that aspect not to be sent to the clients so that the physics system on the clients does not pick them up and process them. I only need the physics systems on the server to process them and their Translation/Rotation to be sent to clients.

But I cannot deselect it in the editor UI, see image below. How can I deselect the physics components in children for the client?



The relevant "client" checkboxes are disabled (however, on root I can select/deselect them).

Other than this, my NetCode experience has been impressively smooth, so thanks to the NetCode team for that!

 

From my current understanding, only the components marked in bold get synced over network (and of these only the properties that are shown when expanding the component). So your physics mass shouldn't be synced over network. If you modified or even removed the component from the Entity on the client it should still be in its original configuration on the matching server entity.
That's at least what my current testing shows. If you want to add something use the Manual Field Checkbox or the [GhostDefaultField], the component then becomes bold and is also added to the generated ghost code.

 

Thank you for the infos! I have the same understanding from the generated code – in my case only Translation/Rotation gets synced (from *SnapshotData).
The syncing/not syncing is less of an issue for me. The issue is more the existence/creation of the component on the client side. I think I may have misunderstood what the checkboxes are for. Back to the manual…

Edit: No, the description is "Expand the components in the list to select where they should be present." So the checkboxes determine where the component is present. I'm wondering how I can uncheck the checkboxes on children (adding a ghost authoring component on a child and unchecking there did not help).

 

Maybe this thread helps:
https://forum.unity.com/threads/net...st-authoring-component-sync-the-scale.803814/
It looks like it should work on all components, whether children or not.

 

@timjohansson Maybe you could point me to a solution?

 

I also asked this question a while ago and got this answer from tim at this thread:

https://forum.unity.com/threads/unity-netcode-0-0-2-preview-1.785558/#post-5233529

Maybe this helps

 

Thanks @Flipps!

Aw, too bad, I was hoping it would work. So currently it's not possible to have child entity components removed after the entity conversion (not just to not send the component, but to not have it exist as in the root's case).

This is my case (simplified here): A parent car entity with four wheel entities that each have physics components on the server, but should not have them on the client. I need the physics system to run on the client (for some client-only effects), but to not have the car and wheels be handled on the client.

Is there any way I can do this via NetCode or do I have to remove the physics components myself, for example in a client-only system that matches certain entities' components? (car, wheels) And will the child entities at some point in the future be also comfortably be checkbox-selectable, and it's only now not comfortably possible?

 

I think you can remove the physics components if you override the methods UpdateNewPredictedEntities and UpdateNewInterpolatedEntities in a partial class like:

Code (CSharp):

1.  
2. public partial class CarGhostSpawnSystem : DefaultGhostSpawnSystem<CarGhostSnapshotData>
3. {
4.  
5.     protected override JobHandle UpdateNewPredictedEntities(NativeArray<Entity> entities, JobHandle inputDeps)
6.     {
7.        inputDeps.Complete();
8.        //Get wheels from entities by LinkedEntityGroup
9.        //remove components from wheels
10.     }
11.  
12.     protected override JobHandle UpdateNewInterpolatedEntities(NativeArray<Entity> entities, JobHandle inputDeps)
13.     {
14.        inputDeps.Complete();
15.         //Get wheels from entities by LinkedEntityGroup
16.        //remove components from wheels
17.     }
18.  
19. }
20.  

 

Thank you!

Yes, that makes sense. Thanks for looking into it (I'm currently evaluating feasibility for my game and estimating how much work is needed).

Yes, I assume to collect all the data, entity components need to be collected via child-parent relationships. I don't see a way yet to avoid these parent-child relationships. Unless I could put a ghost on each child comfortably – that would work for most cases (see cases below).

Given "keep in mind that ghosts with multiple entities is significantly more expensive on the server than multiple ghosts", would it be a possibility to instead of using one ghost on the parent have multiple ghosts on parents and children?

I've collected my parent-child cases and how I'd like to process them in NetCode, trying to minimize data sent and processing power. Perhaps you can use this as input on the "bug". The thing with the four grey things attached represents a car.



Case 1 is probably quite standard. The parent-child connection could even be severed in this case, since its transform could be sent from the server (avoiding work in parent-child transform systems on the client – this may already be the case, I'll have to check).
Case 2 is where I do not even want to spawn an entity for the server child entity on the client.
Case 3 is where the child entity does not need to exist on the server, but it needs to react to physics on the client.
Case 4 is a case where I could either have parent-child transform systems on both ends do the work, and send nothing via NetCode (to avoid costly data collection), or collect the data and send it over the wire, as in case 1.

Currently, I'll be doing this via my own systems, but of course it would be great to have client/server existence checkboxes on child entities plus being able to have the server/client pred/client interp. checkboxes for child entities. Not saying it's absolutely necessary, but to cover my cases above it would be more comfortable

Thanks for reading!

 

Was this implemented?

 

Ok. I was just wondering if it's already there and I missed it. I won't really need it, but as it currently stands synchronizing children is bugged beyond usability.

 

See this post: https://forum.unity.com/threads/ind...amicbuffer-of-29-length.1160462/#post-7505192