Thanks Michael,

I have understand where is the problem talking with the company that build it in solidThinking:
The model was created initially using solidThinking by company A, then saved in the STEP format and a company B have modified it using another modeler (I don't know the name).

If I open the model done initially by company A in solidThinking and I save it in IGES, then with MoI I save in LWO the result is perfect.

Is IGES better than STEP for this kind of conversion?

I attached the file if you want to check.

Antonio