Thanks for the question. You can achieve a similar effect to this by stopping the array for each row before it gets to the end of the spline using a Conditional operator. The conditional operator can choose segments based on their position along the spline. By incrementally decreasing the position threshold you can get a tapered effect. To do this you create a Conditional
operator and Export the Spline Position
parameter. Wire this to a Arithmetic
operator and add an equation that uses the Y Segment Count as a multiplier. I used this equation:
Where Input1 and Input2 are Random number nodes, used to add some variation.
If you want to add an eroded start then this is more work. You can't simply remove the bricks because they determine the position of others further along the spline. Instead we must use a similar approach to swap bricks for null segments - spaces - that have exactly the same size as the brick geometry.
The style gets a little complex, but based on this question we will refine this and include it as a Macro in RailClone 3. In the meantime, please find attached a sample scene.
I hope that helps, please let me know if you have any further questions.