Deterministic physics calculation on two or more connected computers

[sascha.schneider]

Hello,

We have played with the ClothSimulation and the PhysicalWind. The following questions came up so far:

• How to synchronize the wind across multiple computers ? referring to a similar discussion 
• How to achieve a deterministic/synchronized state for the physic-bodies inside the simulation? Is there something similar to
  1. setSyncMode
  2. takeSyncData
  3. applySyncData

Thank you in advance, Regards,

Sascha

 

[silent]

Hi Sascha,

What kind of task you are trying to achieve? Simulate windsock or something like that? It will be much faster and easier to do so with regular ObjectMeshSkinned (and it's relatively easy to synchronize it instead of physics).

Thanks!

[sascha.schneider]

On 4/19/2020 at 4:38 AM, silent said:

Hi Sascha,

What kind of task you are trying to achieve? Simulate windsock or something like that? It will be much faster and easier to do so with regular ObjectMeshSkinned (and it's relatively easy to synchronize it instead of physics).

Thanks!

Hello Silent,

yes one of the first tasks was the simulation of windsocks. Thanks for the hint to ObjectMeshSkinned, this could be a solution for this. I take it as a possible alternative.

Back to the initial question:
How would an approach with the synchronization of physics look like? Is it even possible? 

Thanks,

Sascha

[silent]

Generally speaking making physics run deterministically across multiple slaves is not really possible.

The main approach would be to synchronize objects changes after physics executed on master (no physics calculations should be ever run on slaves).

[sascha.schneider]

Hello silent,

I think I'm getting more of a feel for which direction to go.  Thanks a lot.

Another question, how would you synchronize a ClothObject? Is it possible to access data here and transfer it to others?  Or could it be a valid approach to apply time-triggered physical impulses to all devices synchronized over time?

Greetings and thanks again

[silent]

If you are using ObjectMeshDynamic you can synchronize Vertex / Index arrays via (get/setVertexArray and get/setIndicesArray). The only possible issue is there might be a lot of data to transfer per frame, so you need to test it first. Maybe some approach to calculate and send only diff between two state, use compression and so on.