Objects falling through surface that they shouldn't fall through

[gmaj9]

Hello,

I have a mostly simple scene set up based on the Automotive Bridge Scene asset (Automotive Bridge Scene in Environments - UE Marketplace).

When I start simulating the level, vehicles fall through most segments of the bridge, but stay on top of a few segments (they stay on top of most, but not all, of the curved segments). I compared the physics and collision settings of the two road surfaces that meet up beneath the van in the image I attached, but they seemed to be the same. I am not sure what is going on.

I’m new to Unreal Engine, so there is probably something that I should’ve checked but missed. Thank you for any help you can give!

[StBlueFire (BlueFireSR)]

If you can post the collision settings for your vehicle and all road pieces, someone may be able to help. Its likely object type being set different on different segments, but impossible to know without being able to see the settings.

[MostHost_LA]

Common answers here:

Landscape: Physics Items Eaten By Floor

No worries. Afaik there arent any adverse effects. Note however that physics can go through all collision depending on the poll rate (in engine its called sub step), the speed of the object, and the size of the collision. Essentially, small things fall through a lot. This is just because the calculations to determine a hit have a really high chance to fail to detect an impact when the check for it occurs only before and after the supposedly impacted object. For instance, An ok solution for…

[gmaj9]

Here are the physics and collision settings for the road piece that the front of the van is sinking into:

Here are the physics and collision settings for the road piece that the back of the van is staying on:

Here are the physics and collision settings for the van’s body:

The van’s wheels have separate physics and collision settings, which are the same for each wheel:

[StBlueFire (BlueFireSR)]

You have them set to query only and also ignoring everything. If you want them to not fall through an object you need to set it to block on WorldStatic for both at least. If you’re expect a physics reaction you need to set it to physics as well.

The tl;dr is with any two objects solving collision comes down to looking at the object types they each are. And ensuring that they have the expected behavior (probably block in your case) for the other’s object type.

The longer answer is found here and will help you get an understanding of collision in UE4.

Collision Overview