Creating a bounce part to bounce off floor and walls

Blokhampster34 · January 26, 2020, 7:11pm

I’d like to be able to make a surface that will repel the player with an equal opposite force to that the player hit with.

Essentially I want to be able to make a player fall from a height of e.g. 64 studs, hit the surface, and bounce back up to the original height of 64 studs, not gaining or losing any height.

I also want to be able to make a player rebound off it if they fling into a wall coated in the surface.

An example of this concept would be the Repulsion Gel (The blue one) from Portal 2.

Here is an example of what I want to achieve.

I hope you can help me out!

My current attempt for floor bouncing was to detect when there was no floor under the player, get their height, wait until touching a bounce surface and then use the height difference to calculate the desired velocity. It didn’t work at all, so I won’t link it.

starmaq · January 26, 2020, 7:20pm

github.com

EgoMoose/Articles/blob/master/Vectors/Dot product.md

# Dot product

The dot product is an operation performed on two vectors in any dimension that returns a single number. It is also sometimes called the scalar product, the inner product, or rarely the projection product. The dot product is considered a way to multiply two vectors. Performing the dot product operation is simple enough, but in order to use it in code you will need a good understanding of the mathematics behind the operation. This article aims give a better understanding of the dot product so that you can use it in your games.

## Table of contents

* [Geometric definition](#geometric-definition)
* [Algebraic definition](#algebraic-definition)
* [Case study: Reflecting lasers](#case-study-reflecting-lasers)

## Geometric definition

To start off let’s have a definition for the dot product given vectors U and V.

*“The scalar projection of U onto V multiplied by the magnitude of V”*

*“The scalar projection of V onto U multiplied by the magnitude of U”*

This definition may of course leave you wondering what a scalar projection is, and more importantly how to calculate it. A scalar projection is the amount that one vector travels in another vector’s direction. So if we say that we want the projection of U onto V we want to know how much of vector U is going in the same direction as vector V and vice versa for the projection of V onto U.

This file has been truncated. show original

This article by egomoose shows you how to do this using Dot Products.

Blokhampster34 · January 26, 2020, 7:20pm

ok, ill try this out. Thanks! --

Blokhampster34 · January 26, 2020, 7:32pm

I’m not too sure how to implement this though. I don’t know how to reflect off of the surface when the player hits it because I don’t know how to cast the ray. I can’t have a set direction for the ray because the character could face any direction. This issue leads onto my other issue which is how to get the normal a part hits without rays.

I can’t reflect a ray if I can’t shoot the ray to begin with is my issue.

KazabiteBoltiz · April 18, 2021, 8:24am

Bumping. I wanna know the answer too.