Calculate Surface Area from OBJ File

I need assistance in calculating the surface area from a 3D image file in OBJ format using open-source software. I am currently using MeshLab for this task and would appreciate a straightforward method to achieve accurate results. A step-by-step guide on using MeshLab to calculate the surface area is required to ensure I can follow the process easily.

Key Requirements:
- Calculate surface area from OBJ 3D image files
- Utilize MeshLab, an open-source software, for the calculation
- Provide a detailed, step-by-step guide on the process

Ideal Skills and Experience:
- Proficiency in using MeshLab for 3D modeling tasks
- Experience in calculating surface areas from 3D models
- Ability to create clear and concise instructional guides

Your expertise in this area will be invaluable, and I look forward to your guidance on this project.