Math Q: Compensating for ball radius on a reflection.

Hey guys,

Below is a photo of the current problem I am working on for a mini golf game. To get the shot vector for the computer I reflect the goal position over the wall and shoot at this position. This works great!

Problem: It seems the bigger the ball the less accurate my shots get. I think I need to adjust the Reflection point of the goal to compensate for the radius of the ball. I’m not sure exactly how to do this.

Thanks for your time in advance.


I’m not precisely sure what you want, but here’s the usual smarty-pants solution:

make a fake wall, one radius away. then the calculation is very easy.


amazing huh ?? je keffe

A user and I (the user whose name I do not remember provide the start-up algorithm, I tested and completed it) have answered a question on calculating the ghost-ball and the reflected guideline for a billiard game.

You can check it out and see if it helps : Billiards game. Draw a targetting line - Questions & Answers - Unity Discussions