Reposition decals

[Raitch]

If the arrow was pointing "downwards" all the time, using wAng would be a piece of cake, but it seems to be in different angles depending on where on the sphere you hover. I don't really get this part of the code, so am not sure if it's easy to fix

                ^{BABYLON.Vector3.CrossToRef(start, axis1, axis2);
                BABYLON.Vector3.CrossToRef(axis2, axis1, axis3);
                var tmpVec = BABYLON.Vector3.RotationFromAxis(axis3.negate(), axis1, axis2);
                var quat = BABYLON.Quaternion.RotationYawPitchRoll(tmpVec.y, tmpVec.x, tmpVec.z);
                if (pickInfo.pickedMesh.rotationQuaternion)
                    box.rotationQuaternion = pickInfo.pickedMesh.rotationQuaternion.multiply(quat);
                else
                    box.rotationQuaternion = quat;}

[Wingnut]

Ahh, yes, this is derived from "surface-following Susanne"  (#8 in the series).  Sorry about that.  I gave you a bad answer.

Texture wAng is not controllable or predictable... when the mesh itself is Z-rotating.  *nod*  We might need to say goodbye to quaternions, and try something like billboard mode (pretend camera inside sphere). 

Unfortunately, billboard suffers z-spin near the poles... and that will kill THAT idea, too.

Interesting challenge. 

Have you tried standard plane... with setPivotMatrix at sphere center?   I suppose that method has problems if/when the sphere has some mountains and valleys on it.