I'm telling you it's due to the fact about smoothing groups that are lost when the mesh is exported and imported as mdl. the mdl doesn't have smoothing groups.. so the whole mesh becomes 1 entire smoothing group. therefore those artefacts are born.
There was a solution to this, by detaching faces (opening your mesh), but it doesn't fix the problem when shade-c is applied.. actually makes it worse.
Typical of Gamestudio basically.
This is how complicated a task would be normally <-->
This is how complicated it becomes when in relation with gamestudio <-------------------------------------------------->
