Some OBJ files still give unhandled expression on load - babylonjs loaders

Questions
#1

I seem to be experiencing an issues pretty close to this one looks like the fix should be in though, and I am still getting it.

I have a NurbsCurve created in blender, and exported as an obj.

my Babylon versions are:

    "babylonjs": "^4.2.0",
    "babylonjs-loaders": "^4.2.0",

My loading code is:

    BABYLON.SceneLoader.Load("/assets/3d/", "pathing_test.obj", engine, function (scene) { 
        // do something with the scene
     });

My Obj file looks like:

# Blender v2.91.2 OBJ File: 'ship.blend'
# www.blender.org
o path_test_1_NurbsCurve
v -1.821069 0.000000 10.709910
v -2.349467 0.000000 10.435993
v -2.812101 0.000000 10.134640
v -3.210908 0.000000 9.809603
...
v -0.333340 0.000000 -1.249982
l 1 2
l 2 3
l 3 4

My console errors are:

Babylon.js v4.2.0 - WebGL2
babylonjs.loaders.min.js?b234:16 Unhandled expression at line : l 1 2
babylonjs.loaders.min.js?b234:16 Unhandled expression at line : l 2 3
babylonjs.loaders.min.js?b234:16 Unhandled expression at line : l 3 4
babylonjs.loaders.min.js?b234:16 Unhandled expression at line : l 4 5

So it seems to be having issues with the lines not the vertex now. Thanks in advance if you can help.

#2

the l entry in the .obj is for describing lines. Lines that are not supported in .obj loader.
Can you export without lines ?
If you need lines, I think .gltf format supports it.

ping @Drigax

#3

Ah, the glb format did’nt work as it optimised the path out of existence. As a raw curve, and when converted to a mesh. It just ends up as a single empty transform node.

So I tried obj, I will look at the export settings.

#4

I just tired the Curves as NURBS option in the blender obj exporter, but still no luck.

OBJ file:

# Blender v2.91.2 OBJ File: 'ship.blend'
# www.blender.org
v 9.123311 0.000000 8.439651
v -1.995049 0.000000 8.439651
v -1.976473 0.000000 2.331339
v 4.813529 0.000000 4.435480
v 4.813529 0.000000 1.000000
v -0.500000 0.000000 0.500000
v -0.500000 0.000000 -1.500000
v 0.500000 0.000000 -2.000000
g path_test_2
cstype bspline
deg 3
curv 0.0 1.0 -1 -2 -3 -4 -5 -6 -7 -8
parm u 0.000000 0.090909 0.181818 0.272727 0.363636 0.454545 0.545455 0.636364 0.727273 0.818182 0.909091 1.000000
end

Error:

Babylon.js v4.2.0 - WebGL2
babylonjs.loaders.min.js?b234:16 Unhandled expression at line : cstype bspline
babylonjs.loaders.min.js?b234:16 Unhandled expression at line : deg 3
babylonjs.loaders.min.js?b234:16 Unhandled expression at line : parm u 0.000000 0.090909 0.181818 0.272727 0.363636 0.454545 0.545455 0.636364 0.727273 0.818182 0.909091 1.000000
babylonjs
#5

FYI for anyone else trying to move just a curve over. The STL format seems to kill curves as well just like the GLB. Even when converted to mesh. If I export and import back into blender it’s just an empty object.

To obj seems the way to go if Babylon3D can import it.

#6

Not the first one to hit this issue: Looks like someone opted to script it