[Solved] Calculate a path and then move the agent to a specific point in the path

Some context on what I’m building:
I’m using the pathfinding for NPC agents that have a schedule. When the player enters a scene, the NPC will have a start point and a target point. For example, at 10:00 in-game time, the NPC should be at the station. He starts walking to the station from his house at 9:00. So every time at 9:00, this NPC will calculate a path to the target point and start walking there. Because there are dynamic obstacles, I can’t re-use one path and have to calculate one every time. This process is working perfect with this package.

But now I have a challenge. What if the player enters the scene at 9:30 in-game time?

My own solution (not implemented yet) is a bit messy:
I check that the NPC had a total 60 minute travel time from start to end and he has 30 minutes left, so he should be 50% of the way to his target. So I take the end point and calculate a random path to a point thats roughly 50% of the distance between start/end based on movespeed, remaining time and total distance from start to end. Then from this random point that’s roughly 50% away of the target, I can calculate a new path to the target. But my problem is that the random point at 50% of the distance is never accurate.

What would be perfect, but I don’t know if it’s possible:
When the player enters the scene at 9:30. The NPC agent will know it’s start position and end position. The “normal” path will be calculated from start to end. Then we know he should actually be at 50% of the way again. But this time, we use the original start -> end path and we move the agent to a waypoint that’s 50% of the path length. But I don’t think there is a way to determine the length of a path or put a point on e.g. 50% of 70% of the way in the path.

I hope I gave enough context for my problem. Would appreciate any feedback if you guys have had the same issue before or know of some potential solutions.


If you have the path this can easily be calculated.

ABPath path = ...;
// Create a PathInterpolator helper object
PathInterpolator interpolator = new PathInterpolator();
// Set the travelled distance of the path interpolator to be 50% of the remaining distance.
// Since the interpolator starts at the beginning of the path this will be 50% of the total path length
interpolator.distance = interpolator.remainingDistance * 0.5f;
// Move the transform to the point given by the interpolator
transform.position = interpolation.position;

Hi Aron,

This is great. I wasn’t aware of the PathInterpolator class, but I’m sure this will solve my problem. I will try this asap, thanks for helping me here! :smile: