Hi, I am sorry for stupid question but I have an issue with Harmonic release. I dont know why, but when I use dae file with mesh of some ground model as world base and then I want to spawn a vehicle on the ground (on the mesh, which is not straight as origin plane) the vehicle does not collide with the ground mesh, but it goes through the mesh as soon I start the simulation. It worked in Gazebo classic just fine. But with this release (tried in garden too) it does not work properly… Do And I saw this message in log "Mesh construction from an SDF has not been implemented yet for dartsim. Can anyone, please, help me? just tell me what am I doing wrong… 
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@LukasBrno - this query is probably best directed to the Gazebo team as it does not seem to be ArduPilot specific. Providing an example that enables devs to reproduce the issue will help.
I noticed a problem with the cylinder collisions in Harmonic (Cylinder and capsule sinking through plane · Issue #692 · gazebosim/gz-physics · GitHub) and the issue may be related to that. A good test is to start the simulation paused, and ensure that the vehicle is above the ground collision mesh before unpausing.
Hi @rhys , I did write a Q to Gazebo team too:) I just tried, but it seems convex hull mesh creation in blender helped…
Lukas
Ah - ok. Could be that the normals for the initial mesh were not oriented correctly. If you are still having issues feel free to post examples here and we can take a look.