PS - I am still waiting for the interview results.
Direct On-site after a call from the ANSYS HR.
I was invited for an on-site interview at the Troy, MI office shortly after the phone screening round with the HR. I had to prepare an hour-long presentation about myself and some technical projects and present it to the ANSYS team as well as the OPTIS team. The presentation was followed by 15 minutes of technical discussions with various questions. Then there was a 1:1 interview with various engineers from the team, hiring manager and managers from other teams. It was a total of 4h 30mins. The people were quite friendly and the questions were directly based on my previous experiences. The interview was more like a discussion about some random topics to test our intellect and handling capabilities.