Instance meshes are unstable

[Seyren]

I'm not pretty sure the reason of why is this happening, but when we import meshes and use instance of these ones, they tend to blink until they disappear.

 

This is something that only happened on the website, since when i test it on localhost, seemed to work fine, however this has been happening since ever on some computers and not on others.

 

This is the scene where the issue happens, it's basically two meshes, they both make a floor with roads, the first one is a direct mesh import, but the second one is an instance, see the of the whole function code here:

var Prt_f01_map = function(scene, offset) {	var box = BABYLON.Mesh.CreateBox("box", 1.0, scene);			BABYLON.SceneLoader.ImportMesh("", "../Models/Maps/", "prt_bd01.babylon", scene,		function (mapZone, particleSystems, skeletons)		{			mapZone[0].position = new BABYLON.Vector3(-101.492996, 2.988000, -19.001993);			mapZone[0].scaling = new BABYLON.Vector3(0.001000, 0.001000, 0.001000);			mapZone[0].rotationQuaternion = null;			mapZone[0].rotation = new BABYLON.Vector3(0.000000, 4.712389, 0.000000);		});			var Prt_f01_prt_bd02_inst = 0;		BABYLON.SceneLoader.ImportMesh("", "../Models/Maps/", "prt_bd02.babylon", scene,		function (mapZone, particleSystems, skeletons)		{			mapZone[0].visiblity=false;			mapZone[0].isVisible=false;			mapZone[0].name = "Prt_f01_prt_bd02";						Prt_f01_prt_bd02_inst++;			objInstance = mapZone[0].createInstance("Prt_f01_prt_bd02_inst_"+ Prt_f01_prt_bd02_inst +"");			objInstance.visible = true;			objInstance.isVisible = true;			objInstance.position = new BABYLON.Vector3(-101.492996, 2.988000, -19.001993);			objInstance.scaling = new BABYLON.Vector3(0.001000, 0.001000, 0.001000);			objInstance.rotationQuaternion = null;			objInstance.rotation = new BABYLON.Vector3(0.000000, 4.712389, 0.000000);			objInstance.backFaceCulling = true;			objInstance.useOctreeForRenderingSelection = true;		});}

So, the first one the direct import and the next is the instance.

 

http://puu.sh/evLiR/103395f93a.jpg

 

Here you can see both of the meshes, but when you rotate the camera a bit down for example:

 

http://puu.sh/evLnr/5b63b0e0f0.jpg

 

poof! it disappears.

 

Here's the reproduction of the issue:

 

http://www.diviniaro.com/WGClient/Client/index_sprt_f01.html

 

It's a free camera, so feel free to move it the way you want to.

 

Thanks in advance

Seyren

[amorgan]

I've seen dissapearance like this and seems more related to the octree selection. Could be completely wrong, but try removing the octree selection and see if the probelm persists.

[reddozen]

Pretty sure we're not using octrees in the actual rendering calls.

[gryff]

The last line of the code above is :

objInstance.useOctreeForRenderingSelection = true;

If you look at my Christmas Village piece, it is built on instances - two types of tree, fence posts, wreaths and flashing lights. But the all come from Blender, no octree and not generated in code.

 

cheers, gryff

[reddozen]

then maybe there's an issue with octrees?

[Seyren]

I tried to replace the file with one without hte octree line but now the server replaced it for a blank .js instead, so for now i can't fix it, i'll edit it when this is fixed , thanks in advance

 

EDIT: Commented the line and the issue is still there

[reddozen]

octree reference fixed and the issue is still present.

[amorgan]

The only other thing that I notice is backFaceCulling, set it to false? I wouldn't think this was it, because I would imagine it would just not show it at all from the angles it disappears, but if it were, maybe the normals are wrong in the scene.

 

Otherwise, i will let the big guys solve this.

[Seyren]

Setting it to false didn't solve it either, unfortunately .

 

I guess it can be a babylon bug or something, i don't know.

[GameMonetize]

Could you reproduce it on a simpler case? Or even on the playground?

[reddozen]

It's only 2 models. What would you like simplified, and we can try. We can try to recreate the issue on the playground, but I'm not sure.

[Seyren]

I would like to reprodude it on the playground but the issue seems to only be happening on mesh importing, and since i can only use the default meshes that come with babylon i can't do it :s

 

And also it's easy to create the issue on that webpage, if you move the camera you'll notice that part of the ground disappears, try moving it down

[GameMonetize]

Ok I understand

 

In this case can you reference www.babylonjs.com/babylon.max.js instead of current version. This will help me debugging

[Seyren]

At this moment i'm unable to do so but i'll do it as soon as possible >_<  done by reddozen

[reddozen]

done.

 

I think this is similar to the other times you've fixed this similar issue for me. Every major update seems to break instances or multi mesh objects. I think what's happening is that the parent mesh of the instance that isnt visible is leaving the fulstrum and it's causig the instance to be hidden. That's my best guess.

[GameMonetize]

I already checked this and this is not the case as you can see here:

www.babylonjs.com?INSTANCES

[dbawel]

Is there any chance that the normals on adjcent instances might be infinately close together or have any overlap?  I've observed this before when rendering geometry (specifically cubic) with an infintesimal overlap of normals so small that redraw is somewhat conditional (depending on distance, angle, resolution, etc.) when firing camera rays at different angles.  It might be worth applying a very slight additive postional offset to the instances just for testing purposes.  This has solved similar issues for me in the past.

[reddozen]

It worked perfectly in 1.13, so I doubt thats the case dbawel.

[Seyren]

This bug was also made with an empty project in localhost with nothing more than the two meshes, the project is just 2,45 MB and is enough to make the bug happen.

 

Just open the html and you should see the same thing that is displayed on the link i sent on the first post

 

I hope this helps.

WGClient.zip

[GameMonetize]

Guess what? it was a bug with the LOD engine I fixed it

 

Thank you for reporting this one!

[reddozen]

Thanks as always!

[Seyren]

Thanks to you for solving it