Yes, Rajinikanth is magnetic indeed

The team placed 3D trackers on Rajinikanth's body for executing the magnetic sequence. This is used to match the movements of CGI elements with live action. For the close-up shots, Srinivas avoided using CGI elements since the production unit got the biggest asset from Stanwinston studios with animatronics. So in the close up, all the metal objects and ornaments that were seen on Rajinikanth' body was in fact shot live using the puppet.

Although the animatronic puppet was blended with CGI shots that were made, the vfx team utilized maximum amount of lights in the close-up shots to match up with the CGI wide shots of the Rajinikanth. Different layers were shot with the elements, in the live action layer, the team physically placed the metal objects around in the scene to match the CGI shot when Rajni's character deactivates the magnet and the objects fall to the ground. For Srinivas the execution was simple because the concept was new.

Rajinikanth battles thugs in the train

For the train sequence, Srinivas and Shankar took up this particular scene in the test to get a better perspective of the look and feel of the shots. With the pre-production in place and meticulous planning of the visual effects break down, the team had creative freedom in executing this scene.

Although midway, due to global recession and some constraints the team couldn't continue with the production company they were working with, the project changed hands when Kalanidhi Maran of Sun pictures took over the venture. Srinivas approached some notable companies from Hollywood such as ILM, Café FX and a few others who were excited and happy with the fresh content they we were churning out, but due to the fixed budget, the visual effects in the scene were done mainly in India and Hong Kong. Apart from Stanwinston' animatronics, none of the American companies were used to execute the visual effects and CGI work for the film.