It looks like my triangle intersection code:

                    var EPSILON = 0.000001;
                    var e1 = this.t2.sub(this.t1);
                    var e2 = this.t3.sub(this.t1);
                    
                    var P = ray.direction.cross(e2);
                    var det = e1.dot(P);
                    
                    if(det > -EPSILON && det < EPSILON)
                        return -1.0;
                    var inv_det = 1.0 / det;
                    
                    var T = ray.origin.sub(this.t1);
                    var u = T.dot(P) * inv_det;
                    if(u < 0.0 || u > 1.0)
                        return -1.0;
                    
                    var Q = T.cross(e1);
                    
                    var v = ray.direction.dot(Q) * inv_det;
                    
                    if(v < 0.0 || u+v > 1.0)
                        return -1.0;
                    
                    var t = e2.dot(Q) * inv_det;
                    
                    if(t > EPSILON)
                        return t;
                    return -1.0;

is not working properly. If i use the triangle as an emitter it looks like the first image. But if i use it as a normal object it looks like the second image.

Any ideas?

If i use the triangle as an emitter it looks like the first image. But if i use it as a normal object it looks like the second image.

Hey and thanks for your answer :)

Okay, maybe my triangle normal vector calculation is not correct?

                var u = this.t1.sub(this.t3);
                var v = this.t2.sub(this.t3);
                var normal = u.cross(v);
                return normal;

where do you normalize the normal?

If i change the code to this:

 var hitPoint = ray.origin.add(ray.direction.multFloat(hitDistance * 0.99));
 var normal = hitObject.normal(hitPoint).normalize();

it still doesn't work...

Hi and thanks for your reply,

My triangle before:

new Vector3D(-6,5.5,5),
new Vector3D(6,5.5,5),
new Vector3D(0,5.5,1)

and now:

new Vector3D(0, 5.5, 1),
new Vector3D(6, 5.5, 5),
new Vector3D(-6,5.5, 5)

but the problem still exists.