I just figured this in the tyflow manual :
"The total number of evaluations per binding per frame can be calculated as (bind steps) x (simulation time steps). The higher the total number of evaluations, the more accurate the solver results will be. For granular simulations, a simulation time step of either “1⁄4 Frame” or “1⁄8 Frame” with bind solver steps of 5-10 is often adequate. For hires cloth simulations, bind solver steps may need to be much higher in order to maintain cloth stiffness."
so to set the time step in the main settings of tyFlow form 1 frame to 1/4 frame solve the intersection errors, so I don't need to use the surface test operator anymore.
But I have to set all the others parameters again
"The total number of evaluations per binding per frame can be calculated as (bind steps) x (simulation time steps). The higher the total number of evaluations, the more accurate the solver results will be. For granular simulations, a simulation time step of either “1⁄4 Frame” or “1⁄8 Frame” with bind solver steps of 5-10 is often adequate. For hires cloth simulations, bind solver steps may need to be much higher in order to maintain cloth stiffness."
so to set the time step in the main settings of tyFlow form 1 frame to 1/4 frame solve the intersection errors, so I don't need to use the surface test operator anymore.
But I have to set all the others parameters again