ThreeJS: Some material texture faces / triangles not rendering - three.js

Question

I have a .obj and .mtl which load textures from .tga files. This all seems to work / look fine in 3D modeling software, but when loaded with three.js (THREE.WebGLRenderer({ antialias: true })) some of the object's children, (specifically between the knees and the calves, but not, for example, the pockets and legs), seem to have a transparent jagged gap / empty triangles.
(Tried turning on antialiasing, changing the overdraw value, turning off transparency, etc.)
Loader function:
threejsHelper.helpers.loadObject('objects/pants/MaleBaggyPants.obj', 'objects/pants/MaleBaggyPants.mtl', {
blinn1SG: (new THREE.MeshPhongMaterial({ color: 0xffffff, transparent: false, opacity: 1.0, overdraw: 0.5, map: threejsHelper.helpers.loadTexture(app.manager, 'objects/pants/button.tga') })),
blinn2SG: (new THREE.MeshPhongMaterial({ color: 0xffffff, transparent: false, opacity: 1.0, overdraw: 0.5, map: threejsHelper.helpers.loadTexture(app.manager, 'objects/pants/back.tga') })),
blinn4SG: (new THREE.MeshPhongMaterial({ color: 0xffffff, transparent: false, opacity: 1.0, overdraw: 0.5, map: threejsHelper.helpers.loadTexture(app.manager, 'objects/pants/front.tga') })),
blinn5SG: (new THREE.MeshPhongMaterial({ color: 0xffffff, transparent: false, opacity: 1.0, overdraw: 0.5, map: threejsHelper.helpers.loadTexture(app.manager, 'objects/pants/pocket.tga') })),
blinn6SG: (new THREE.MeshPhongMaterial({ color: 0xffffff, transparent: false, opacity: 1.0, overdraw: 0.5, map: threejsHelper.helpers.loadTexture(app.manager, 'objects/pants/back.tga') })),
blinn7SG: (new THREE.MeshPhongMaterial({ color: 0xffffff, transparent: false, opacity: 1.0, overdraw: 0.5, map: threejsHelper.helpers.loadTexture(app.manager, 'objects/pants/front.tga') }))
}, function (object) {
object.rotation.x = (-90*Math.PI/180);
object.rotation.z = (-90*Math.PI/180);
app.scene.add(object);
app.ready = true;
});
Helper functions:
...
loadTexture: function (manager, path) {
var texture;
if (path.split('.').pop() == 'tga') {
var loader = new THREE.TGALoader();
texture = loader.load(path);
} else {
texture = new THREE.Texture();
var loader = new THREE.ImageLoader(manager);
loader.load(path, function (image) {
texture.image = image;
texture.needsUpdate = true;
});
}
return texture;
},
loadMaterial: function (mtlPath, textures, complete) {
var loader = new THREE.MTLLoader();
loader.load(mtlPath, function (materials) {
materials.preload();
if (!!materials.materials) {
for (var key in materials.materials) {
if (key in textures) {
materials.materials[key] = textures[key];
}
}
}
complete(materials);
});
},
loadObject: function (objPath, mtlPath, textures, complete) {
app.helpers.loadMaterial(mtlPath, textures, function (materials) {
var loader = new THREE.OBJLoader();
loader.setMaterials(materials);
loader.load(objPath, function (object) {
complete(object);
});
});
},
...

Answer 1

You seem to have extra vertices along the seem on both the objects which I think will screw with the triangulation.
Remove these vertices that are not needed and I'm 99% sure it will fix your problem.
I also noticed the model is at a very small scale.

Answer 2

I had the same problem. Some triangle didn't properly render on Threejs while it properly rendered on my OpenGL app.
I solved this trouble by using Uint32Array instead of Uint16Array to define the index of the geometry. I just put this line of code and everything worked like a charm.
const indices = new Uint32Array(faceDict.index);