The “Stepping” sections can be described as RealFlow accuracy. The more time steps, the better and more precise the simulation will turn out. The parameters already indicate that RealFlow uses an adaptive method to calculate the best number of steps within the specified range between “MIN and MAX substeps”. To achieve a fixed time step, "MIN substeps" and "MAX substeps" must be equal.
Stepping (Liquid - Hybrido Solver)
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This is the number of steps the solver uses to move the particles through the grid.
Collision Fractions Computation Mode (Liquid - Hybrido Solver)
Calculating accurate fluid-object collisions is a very complex process, and really depends on the collision object's shape and geometry. Therefore it is – in some rare cases – necessary to differentiate and change the method of detecting collisions. Please note that there is normally no reason to switch from “Face area” to “Supersampling”.
Face area
This is the fastest method and can be used in most situations. The good thing is that “Face area” does not add artificial friction to the fluid when it is colliding with an object. This means that the fluid's behaviour is not affected. The other side of the coin is that some collision objects are not recognized correctly – this is mainly the case with sharp-edged or spiky objects. Here, it is possible that the “Face area” method might not be accurate enough and you should consider using “Supersampling”.
Supersampling
If you can see collision problems which cannot be solved with “Surface offset”, “Domain offset”, or smaller cell sizes then you might want to use this method instead of “Face area”. Supersampling is very accurate, but also computationally intense and adds some artificial friction to the fluid. With curved surfaces, “Supersampling” should not be used, because you might see and unwanted alias effect in areas where the fluid touches the object's surface. It is, however, a good choice if collision objects show many sharp angles.
Samples
With “Supersampling” set “Yes” you can adjust the accuracy of the method here. The entered value will be raised to the power of three to get the final number of samples inside a cell. For example, when “Samples” is set to 3 then the total number of samples will be 3 x 3 x 3 = 27.
OpenCL (Liquid - Hybrido Solver)
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