> Benchmark on these two file format (STP, STL) regarding simulation efficiency?
There is no difference in the simulation execution for these two file formats. The calculation of the mass and inertia happens before simulation begins. STEP files tend to be more detailed so rendering the animation can take longer, but since that is typically handled in a separate processor thread it doesn't normally slow down the simulation speed.
> Does SimScape re-calculate its moment of inertia very time step through integration, or just apply a coordinate transfer?
No, the masses and inertias are calculated at the start of simulation.
> How can we extract information like moment of inertial out of the STP file.
You can usually get it from the CAD system. If you use Simscape Multibody Link, the masses and inertias are exported automatically. If you export STEP files, you can get the calculation of the mass and inertia from the Simscape Multibody Solid block (see Solid Simscape Multibody Solid Block Documentation), section "Derived Properties".
--Steve
