Why does my player fall through the floor only when I add geometry.

[canimeaiwor]

First post here, and I’m a newbie with unreal engine (Not with software development in general however), I do have some experience of programming 3D using raw API’s such as OGL etc.

Anyway… I know next to nothing about the specifics of UE5, so I’m experimenting with a “blueprint” for the first person game setup.

Everything is working perfectly, all makes sense I understand what’s happening, if I click play, I can walk around my game level etc, no problem.

I’ve cleared everything out ready to build something new, leaving me with just the layer of cubes that form my “floor”, press play, everything’s great.

HOWEVER…

The second I add any other asset to the scene, my player instantly starts to fall through the floor when I press play.

All I have added is a simple piece of wall geometry, it’s a simple static mesh, it’s on my “floor”, my player start has not moved, and is still also above the floor as can be seen here:

When I hit play, this is what I get, and I can’t in anyway move.

I don’t know if this has anything to do with it, but my player start says this:

No matter what I do, and it was like that ever since creating the blueprint template.

As soon as I delete my bit of geometry however, everything goes back to normal, my player stays on the floor and I can move around again.

I understand the principles of having colliders and such like (GoDot uses the same thing) , and I can see how the floor is the collision mesh for the player, but what is a mystery is why it suddenly changes the way it does as soon as I add new geometry to the playfield.

I admit, I don’t yet know enough about UE5 to work this one out.

Any experts in that can point me in the right direction, greatly appreciated.

[Mind-Brain]

Hey @canimeaiwor!

You’re not falling through- the player can’t spawn due to the BadSize error.

This means something is blocking the character from being able to spawn in that location. Try dragging it upwards first- it’s ok if you spawn in the air. After that, try deleting the player start and adding in a new one.

If that doesn’t change it, make sure the collision of your new wall there isn’t way bigger than intended.

Hope that helps!

[canimeaiwor]

Hi @Mind-Brain Many thanks, I’ll try those things over the weekend and let you know.

I suspect however, that you might just have hit the nail on the head, as my assets all have very huge mesh areas on them due to me screwing up the origin point in my 3D editor.

That wall segment you see in the screen shots above is actually -7000 ish pixels x, and a few thousand minus in the y direction from where my movement gizmo is, so it has a stupid large bounding box around it.

As soon as you mentioned bounding size, a penny dropped in my head.

Not figured out how to move the origin on an asset in UE5 yet however

Many Thanks

[canimeaiwor]

Hi @Mind-Brain you hit the target, it seems that my model cannot be used as is. I have created an entire level as one Huge FBX file, using Sketchup. It’s actually a recreation of some old steel factories that no longer exist for the local history society, the eventual aim is to visit local schools with it to show the children what was there.

Part of the model has a 120 meter high smoke stack, and so the top of the level was way up there, along with a full bounding box that stretched 2191 meters in both directions.

It seems that UE decided to just encompass the entire thing in one huge collision box rather than around the various pieces as I’d hoped it would (Similar to GoDot).

For reference, this is what I’m talking about:

I think, I have a lot more to learn before I can just import this into the first person blueprint and walk around it.

Thanks for your help!