Resolved Terrain with Dots (Physic, and global approach)

Hello,

I saw recently that Terrain Collider were supported. In fact it's on the built-in/compagnon list, but there is no such convertion, is that a manual error ?
Anyway someone on Discord was nice enough to show me a code sample here.

So I took it (only the needed part) and openned the Physic samples. I went to the parade scene (collisions folder if I'm right), created a small default terrain 10*10 that I put under the "objects". Obviously when I hit play the terrain disappear because it's not supported by default by Entities.Graphics. But the collider is there and the objects won't get through. That's nice, except... it's horribly slow ! I check in the profiler and the job of the narrowphase takes 50ms. Most of it comme from the mesh and convex collider, so does it mean that the terrain collider is not production ready?

On a more general note, I always read on internet that unity terrain is less performant than a mesh. But I'm not sure that the people who say this, are thinking about a mesh with a splatmap shader and the hole support (quite tricky with the collider). In my mind, the terrain tool should should generate the same thing when the build is generated, but I don't find any information here.

So, what's the good approach today with DOTS to handle and stream a big terrain (only limited by the computer), from a rendering and physic point of view ? I'm curious about a small one too.

Thanks !

 

Infortunately it is, I think, static flag, no PhysicMass, no PhysicVelocity... I just tried to add a kinematic mass just to check, same thing. I'll report it I guess then.

Spoiler: Images

But without this issue, is there a performance issue at the moment between the terrain approach and the meshes approach? In fact a height map collider looks like it could be smarter than a mesh collider, no? Even if I don't know about dots streaming and terrain.

 

I think I'm missing something isn't the "officially supported method to generate a terrain" the same as "generating the terrain from the built-in Terrain Collider" ? Or there is a doc somewhere I don't know about ?
I mean, I would have done the same thing that in the code sample at the beginning.

Oh I'm stupid, if the code ask for triangle collision method, it will probably be the same result as a mesh.
I'll try tomorrow to convert a simple terrain (with some height changes) to a mesh, and compare both !

 

So , inside the ColliderParade - Basic scene (PhyscisSamples).
I added a default flat square terrain of 30*30 with still the default resolution 1024 (that hurts, the mesh is the perfect duplicate). Also I removed the cylinder and the suzane to be fair with the builtin physic.
Then I tried these :


- No Dots config (mono + terrain) : when everything stop falling I have less tan 2ms of player loop
- Dots with Terrain mesh (definitely stupid if you need the same geometry, I should have think 2sec) : when everything is down, 550ms on the narrowphase
- Dots with Terrain mesh (hull convex) : player loop around 3ms with narrow phase at 0.15s, but it's pretty much just walking on a plane at this level
- Dots with Terrain collifer (heighmap) : slow down like crazy when hitting the terrain -> 2 workers 42/62ms on narrowphase create contact job. Reducing the terrain details don't change much (I went down to 8/96 config), most of the time there is just one worker at 100ms.

Well I guess it's time to wrap the unity package and create that bug report, except if you're telling me that's normal @schembri-unity .

Thanks and have a nice day !