UE4 implements a SmoothStep function in Runtime/Core/Public/Math/UnrealMathUtility.h, here is the code:
static float SmoothStep(float A, float B, float X)
{
if (X < A)
{
return 0.0f;
}
else if (X >= B)
{
return 1.0f;
}
const float InterpFraction = (X - A) / (B - A);
return InterpFraction * InterpFraction * (3.0f - 2.0f * InterpFraction);
}
I’m guessing this is what the custom node needs to be:
