Get bounding box of imported gltf/glb model

Aquivion

Hello everyone,

I have imported a landscape model (as glb file) into godot. The model loads as a Node3D in the scene tree. I want to know the bounding box of the model, so that I can position other elements dependend on that. Question sound trivial, but for some reason i am having a hard time figuring this out. I also couldn't get it to work with MeshInstance3D node and the get_aabb() function, because the model is not type of MeshInstance3D.

The editor already shows the bounding box (orange box) in the image. I wonder why they don't just add the size of it as information somewhere.

xyz

You need to call get_aabb() on the mesh instance node that's within the imported scene. So something like:

$imported_scene/mesh_instance.get_aabb()

The specific node path depends on the structure of the imported scene.

Aquivion

xyz
Thank you for your response, but unfortunately the imported scene does not have a "mesh_instance" under it.

xyz

Aquivion It must have a mesh instance. Otherwise it wouldn't be able to display any meshes.

My example was a pseudocode because you didn't show the structure of the imported scene. Instead of literal "mesh_instance" you should put the exact node path that leads to the node of the MeshInstance type, containing the actual mesh.

The gist is, you need to call get_aabb() on the MeshInstance node somewhere within the instanced scene, not on the scene's top node, because the top node would in general not be a MeshInstance

Aquivion

xyz
Thanks again. How do i find the node path that leads to that node of type MeshInstance ? I tried it with you "mesh_instance" but this didn't work.
Here is what my trial looks like: TerrainModel is the imported Node3D model which created itself, when i dragged the "MountainRiver.glb" into the scene.

xyz

Aquivion TerrainModel is a scene that is nested within your MountainRiver scene. The mesh is probably in there. Take a look. You can go inside the scene by clicking the clapperboard icon in the scene tree. This icon is also a sign that the node is actually a scene.

Aquivion

xyz

Ahh ok i have found the MeshInstance3D Node, thank you 🙂 But i still fail to find the correct property path 🙁
This is how it looks when i opened the TerrainModel scene:
But i still couldn't find the correct property path ... It has to be under Export1 somewhereb

Aquivion

Ok even the export1 node seems to be null during runtime:

xyz

Aquivion Let's see the main scene too.

Btw there are 4 error messages. What are they saying?

Aquivion

xyz

So i only got 3 errors now, don't know where the forth went. But basically only saying that Node "root/Node3D/MountainRiver/Export1/mesh" does not exist

About the main scene: I have a root Node3D which holds the glb scene "MountainRiver" (previously called TerrainModel). When i open up MountainRiver scene see a Export1 Node in it which seems to hold the MeshInstance3D (as seen in the inspector in my last post)

This is the main scene + errors

The root node "Node3D" has the script attached to it, that you can see there.

xyz

Aquivion Almost there 🙂
According to your latest screenshots, the proper path to MeshInstance node is $MountainRiver/Export1. Since its mesh is not a node but a property of the MeshInstance node (as Zini already pointed out), you need to access it via dot syntax.
So to get a reference to MeshInstance node you use:

$MountainRiver/Export1

And to get a reference to its mesh object you use:

$MountainRiver/Export1.mesh

Knowing that get_aabb() is a method of the MeshInstance object, you call it like this:

$MountainRiver/Export1.get_aabb()

Zini

There is no node named mesh (as the error correctly tells you and as you can see in the scene tree). mesh is just a variable of the node class MeshInstance.

Aquivion

xyz

God thank you, finally got it. I thought accessing the Export1 node would also not work because it was null during debugging. But now it works, thank you very much 😃