question

Could you just add an invisible cube around the extent of the animation in the model? This would give it a huge bounding area.

@rhumbaflappy, as I posted, I already tried that, in two different ways:

- with small triangles placed around the animation extent as separate objects. Didn't work, even if the LOD radius sphere clearly increased.

- with the same small triangles, this time as part of the skinned mesh itself, making the skinned object bigger. Didn't work as well.

The problem is not just a generic culling issue, it seems that skinned objects are handled differently because, in the same object, I have another item that moves together with the skinned character, but it's not moving "because it's skinned", it's really moving its center, and this item is not culled.

I think this is somewhat related to the fact the .GLTF format doesn't have an overall bounding box stored in the file ( like the .MDL format ), but rather each part has its own extension values so, it's likely up to the app that loads the file to calculate the overall bounding box, and cleary a skinned mesh that moves outside the boundaries would confuse it, because the only way to know the real bounding box in that case, would be scanning the skinned animation and figuring it out what the real extents would be.

This is tricky, that's why maybe a way to override the bounding box in another way ( maybe in the object XML file ? ) might be useful.

@virtuali, Umberto I have the same issue with a project I am working with, the object transform from small to large.. so the bounding box being calculated at the smaller size causes issues.

You will need to add a cube as suggested by rhumba, however the caveat is, it needs to be done to all LODs.. the bounding box is currently calculated based on the last LODs loaded.. so if you add this cube only to your LOD0, since LOD5 is loaded last.. the bounding box will remain small.

If you add the cube to all LODs.. the bounding box will be calculated properly.

Hope this helps.

S.

@Simbol,

Please read my message carefully, I'm perfectly aware we can place extra geometry to artificially enlarge an object bounding box AND we should do it for all LODs, this usually works, but it's not the issue here.

The issue here is a DIFFERENCE due to the fact my object is made of just two meshes, both animated, but ONE is Skinned, the other one it's not. And it's ONLY the Skinned mesh that gets culled, even if it's part of the same gltf and the same LOD ( I only have 1 LOD, btw ) and their animation covers exactly the same area. The only difference between them is the static mesh moves because its animated itself, while the Skinned object moves because its *Bones* are controlling it.

I even tried to add those extra polygons ( covering the whole animation area ) directly attached to the Skinned Mesh, effectively making the skinned mesh itself larger, but it still gets culled as soon the screen crosses the bounding box, but the skinned object is not there anymore, so it shouldn't be culled.

I wouldn't expect the sim to be able to deal automatically with these fringe cases, that's why having the ability to set some kind of parameter in the object XML, to override the automatic calculation of the bounding box, could be useful.

Or, if anybody found a workaround that would work for SKINNED meshes, I would be happy to hear it.

@virtuali I checked your sample and it makes sense it's not working.

- You tried to extend the skinned object bounding sphere by adding an independent "Plane001" object. That won't help, it will just create an independent object with a dedicated bounding sphere.
What you want to do is add geometry to the skinned mesh directly.

- In this particular case, there's a better alternative. Your skinned animation shouldn't move the character and you would have to use the root node to move him around so that the bounding sphere moves with him. (That's why the kart doesn't disappear, you're moving the node so the bounding sphere is following)

Does that make sense to you?

Regards,
Sylvain

UPDATE

I finally found a workable solution:

When I just added the dummy geometry to the actual skinned mesh, it didn't work very well, the skinned object was still getting culled from some angles.

What seemed to work, was adding the dummy geometry AND remove all the bones influences from their vertexes, so instead of wobbling/moving around with the skinned mesh, they just stayed in place to create the larger bounding box.

This resulted in good visual culling.