float maxx = -Float.MAX_VALUE, minx = Float.MAX_VALUE;
float maxy = -Float.MAX_VALUE, miny = Float.MAX_VALUE;
float maxz = -Float.MAX_VALUE, minz = Float.MAX_VALUE;
FloatBuffer positions = mesh.getFloatBuffer(VertexBuffer.Type.Position);
int limit = positions.limit();
for (int i = 0; i < limit; i += 3) {
float x = positions.get(i);
float y = positions.get(i + 1);
float z = positions.get(i + 2);
center.addLocal(x, y, z);