Why physics cube doesn't fit with the mesh?

[MeshPromo]

I'm making this vehicle object for a friend's vehicle mini-game. She needs the physics as simple as possible (cube) and it should be fitted to the vehicle's surroundings.

Especially if the physics doesn't fit with the bottom of it, the vehicle's treads either float or go underground as she said.

When I set the physics in the uploader, it shows as exactly fit to the mesh object as I needed. (bellow screenshot)

 

But once uploaded, the physics is above the treads. (bellow screenshot)

 

So I tried to add physics in all the different ways, "from file", "Cube", "Bounding Box" and the step2 and step3 settings. But always end up as in the above photo.

She can simply add a prim, but it will add one more Land Impact, so she prefers the built-in physics.

Is this some SL bug or is there any solution to fix this?

Highly appreciate any help.

 

PS: After messing with the mesh for a while, I just thought to add 8 tiny triangles at each corner, to expand its bounding box. So that way I could able to fit the physics to the treads. Now when I rez the model on the ground, it looks like a bit floating as the triangles touching the ground. As my friend concerns about the physics of the vehicle, this way it will work. Besides, I remember most of the vehicles float a bit upward than the ground upon rez, but once touch, it hits the ground.

Still, I like to understand why the uploader doesn't add the physics to the exact bounding box and instead shrunk the physics.

 

 

 

 

Edited May 26, 2023 by MeshPromo
Found some solution after testing for a while.

[OptimoMaximo]

3 hours ago, MeshPromo said:

I'm making this vehicle object for a friend's vehicle mini-game. She needs the physics as simple as possible (cube) and it should be fitted to the vehicle's surroundings.

Especially if the physics doesn't fit with the bottom of it, the vehicle's treads either float or go underground as she said.

When I set the physics in the uploader, it shows as exactly fit to the mesh object as I needed. (bellow screenshot)

 

But once uploaded, the physics is above the treads. (bellow screenshot)

 

So I tried to add physics in all the different ways, "from file", "Cube", "Bounding Box" and the step2 and step3 settings. But always end up as in the above photo.

She can simply add a prim, but it will add one more Land Impact, so she prefers the built-in physics.

Is this some SL bug or is there any solution to fix this?

Highly appreciate any help.

 

PS: After messing with the mesh for a while, I just thought to add 8 tiny triangles at each corner, to expand its bounding box. So that way I could able to fit the physics to the treads. Now when I rez the model on the ground, it looks like a bit floating as the triangles touching the ground. As my friend concerns about the physics of the vehicle, this way it will work. Besides, I remember most of the vehicles float a bit upward than the ground upon rez, but once touch, it hits the ground.

Still, I like to understand why the uploader doesn't add the physics to the exact bounding box and instead shrunk the physics.

 

 

 

 

Depending on the size, it may automatically revert to convex hull if the system finds that the size is smaller than the switch threshold