Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

YL2 - Cum dynamics

odesodes Administrator
edited October 2017 in Patreon updates
This is a reposted submission from Patreon. Due to Patreon's terms of service, which disallows adult content to be publicly viewable, we had to make some posts patrons-only. Now we're reposting these submissions here on the forum, for everyone to view.

Originally posted Aug 29 at 4:20pm.

In YL2 (the successor to Yiffalicious), we want to improve virtually every part of the app compared to its predecessor. Cum is no exception. So this past month we decided to spend time investigating how we could improve cum. After lots of testing and experimentation, we're pleased to say we have arrived at a system that should offer a far better experience from before.

This new system is composed of multiple parts - each one tailored for a specific purpose that takes both the technical (performance, memory usage) and the artistic (quality, final look) into consideration. These parts are:


The particle system is what simulates cum as it shoots out from a cumming character. I.e. it's the system that is responsible for cum in mid air. Once a cum particle hits a surface, it transitions into another state (covered below). So in essence, the particle system is the foundation for all other cum effects. Without it, there wouldn't be any cause for any of it!

Yiffalicious (1) also had a particle effect for the cum. However, that effect was quite crude. This time around we're rendering the cum in such a way that thickness, shape and liquidity are considered.



This effect was very tough to achieve. We're using a multitude of different tricks to get here. It's hardly perfect, but it's far better than last time, and also does it in a reasonably efficient manner. It has a slightly higher cost than the crude particles from before, but I think it's worth it.


If a cum particle collides with the environment, we spawn a cum decal at that location. This time around, we use thickness and normal maps when rendering these decals, offering a far more realistic look than previously. Furthermore, by using texture atlases we can render all decals in a single draw call, making them very performance efficient.

(Stepping through the 8x8 texture atlas)

(Spawning cum decals on particle collision)

This new system is also a bit better at adapting its shape to whatever geometry it hits.

(Spawning decals on irregular geometry)


Getting cum to work on characters was very tough. Unlike the environment, the mesh (surface) of a character is not static. A body is able to deform its surface in a lot of different ways. This posed two very difficult problems.

1) How to collide against a dynamic mesh with reasonable resolution and performance.

Ideally, you'd want to collide against a mesh collider that accurately represents the surface of the mesh. Unfortunately, calculating such a collider is extremely expensive, and something you only want to do once (i.e., not for a changing surface). So we had to think of something different...

2) How to spawn decals on a dynamic mesh that may change later on (i.e. inflation).

We're happy to say we've managed to solve both of these problems using a custom solution that approximates the surface yet generates a valid surface point. In many ways we're cheating, but that's fine as long as the final result looks OK.

There's a small cost of spawning the cum decal on a character using this solution, but once that has been done, it has virtually no performance cost at all, no matter how many are spawned.

Wrapping it all up

All three systems working in conjunction in a scene.

Character creator progress

Although we've mostly been working on cum this month, we haven't forgotten about the character creator. We've actually spent a huge chunk of time trying to solve many technical as well as artistic problems regarding it.

With the character creator in YL2, we want to push the limits of what is possible. We want to do the furry community justice in a way that hasn't been seen yet in any furry 3D app/game. In pursuit of this goal, we have identified several unique features we want to implement, as well as the problems that come with trying to achieve them. And this is where we've managed to make some significant progress this month. One of the hardest problems we identified has been solved, and the implications of this are immense. We didn't know if it was possible, and a huge part of our vision depended it. It feels amazing we we're able to solve it.

I understand I'm being vague. I'm not one who likes to hype things up before we have something to show. In the coming months, we will explore just how far we can push this new tech, and once we have enough content, we will share it with you. Development is looking very promising and we're extremely excited.

In the mean time, here are some character creator heads Dogson has been working on:

Canine heads

Some morphing

Shark heads

Neoteny heads

A comment from Dogson on Neoteny heads:

"My main thought with the neoteny faces is that it is generic enough for users to fill it in with various appendages such as ears, horns or other objects and it will function as a jack-of-all-trades faces. Sometimes generecy can fill a function. for more about neoteny, please visit this wikilink: ".

It goes without saying all this is very WIP and does not represent the final product.


This past month we've been investigating and implementing cum systems to be used in YL2. We've also been working on highly custom tech for our character creator, that seems very promising in our pursuit of achieving something truly unique. In the coming months, we will hopefully have something awesome to show you guys. We're extremely excited about the development.

- odes

Sign In or Register to comment.