Sorry if this is the wrong place...
I need models to look like map objects, you know, with sharp edge shading rather than smooth shading as all the models tend to have. How can this effect be acheived?

unweld all the vertices on the model

my.material = mat_flat;

You can try that, but I don't think it'll work...

When a model does its lighting, it gets the direction of a face through its vertcies averages. therefore, all normals are interpolated, and provide that smoothness you see (gaurad shading).

You can however write a shader that bypasses this...