"From Earth" takes place close to the year 3,000 when one woman and one man, Zenaida and Anthony, are sent to a remote alien planet. After fifty years in cold sleep, they find themselves on a recently industrialised world being hunted by an alien government. They have only their wits, athleticism and the remains of their equipment to keep them alive. In this first person singleplayer experience, the player takes control of Zenaida Liu upon arriving on the planet. From Earth's gameplay is very much about your relationship to this world and its technology, requiring you to figure out how it all works and encouraging cooperation with the local population. Nothing about the alien technology is explained to players. It's about experimentation and learning what's what and how things on this planet work. The player also has some athletic abilities, such as climbing, wall running, hanging on ledges and so on.

Report RSS Climbing System

The climbing system kind of started from aesthetic point of view. I didn't want to use standard first-person jump techniques, ala Half-Life 2, where you can simply press +jump and fly upwards. I wanted a stronger sense of momentum, where you had to speed up before being able to jump. I also wanted to learn more at animating, and doing climbing animations was a good way to start.

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If you haven't heard about From Earth before, read the outline of the project here.

The climbing system kind of started from aesthetic point of view. I didn't want to use standard first-person jump techniques, ala Half-Life 2, where you can simply press +jump and fly upwards. I wanted a stronger sense of momentum, where you had to speed up before being able to jump. I also wanted to learn more at animating, and doing climbing animations was a good way to start.

The player simply walks to a cliff or box and if the cliff is one that the player can climb, it will show a hint on the HUD. The default key for climbing is the HL2 +jump key, spacebar. The player can climb 128 high, where in HL2 the player could only jump to 56 at max. There's three different animations for different height types. Each climbing animation for a height type is a blended animation of two different heights. After this I started experimenting with more animations and climbing abilities, and so came the hanging system, where the player can grab ledges while falling. While hanging they can move left and right, let go and fall down, and climb up if there's enough empty space. Players can slide on the ground, which helps them to get under objects without having to stop running to crouch. The ladders in From Earth are also their own entity that are integrated into climbing system.

Of course, having a movement and climbing system so vastly different from Half-Life 2 requires a lot more playtesting than usual. Even something like jumping has taken its time to develop. At first, the jumping animation was originally a lot slower. Players didn't take off from the ground until a certain part in the animation, which caused a small delay. This created problems where players would repeatedly fall when trying to make a jump, not having pressed +jump early enough. I increased the animation speed to decrease the delay.

Some of the control schemes also create problems. To perform a front wall run, for example, the player first needs to run forward towards a wall. If there's a wall in front of the player that the player can wall-run, then the player will start doing so automatically. The player can then press +back to jump backwards. The HUD hint says that you have to press both +forward and +back at the same time. In the frame you press +back you don't need to be pressing +forward, but if you stop pressing it any sooner the game will assume you want to stop wall-running and it will no longer register your +back as a jump. If I only had the HUD hint say +back, as I noticed in live playtests, that a lot of playtesters would first stop pressing +forward and only then press +back. I didn't use +jump for doing the backwards jump, because the wall the player is running across might also have cliffs that the player could hang on to, and +jump is reserved for that action.

Side wall-running works a little bit differently. If you want to jump to the right while wall running a wall to the left, you need to look to your right and then press +jump. If the player reaches a wall, the player will automatically stop side wall-running. If there's a cliff there, the player can start hanging to it normally with +jump, or the player can continue to front wall-run that wall. While sidewall running, the player might also want to quickly stop wall-running without losing a lot of momentum. In these cases the player can simply press +duck.

I also changed running to be toggled on and off. This was because of how some of our more complex platforming puzzles required the player to maintain a high momentum. The player needed to be able to run right after performing climbing animations. Having to press +jump (to climb up the cliff they are hanging to it), +forward (to move forward), and +speed (to start running) was too complicated and would often result in players slowing down in a critical moment. The climbing system has a "memory of momentum" where it will return part of the velocity it had before starting a climbing animation.


Making a whole new climbing system for a Half-Life 2 mod is a lot work, and a biggest part of that is tuning the system and finding the best control scheme. Although I think the climbing system itself is there to stay, some parts of it such as being able to hang on poles, balancing, climbing on airvents, and such, might end up being candidates for the trash bin. They simply may not be good enough, or might not inspire enough puzzles to justify their presence in the game. I also thought about being able to climb pipes, but that might have created only new problems. If the player can climb only one type of pipe, then why not every type of pipe in the game? Why not these pipes in the elevator shaft (in an area where the player has to figure out how to get elevator to work)? On top of that, it would have been a lot of new animations to create and more programming for something that the player was already able to do to some extent with hanging and ladder climbing.

One thing that the climbing system caused was that I had to rethink a lot of the level design. In Half-Life 2 the player can only jump up to 56 units, as I said. In From Earth the player can climb 128 units if the wall is solid, but she can also do a wall-run and then hang on a ledge. If this is not enough, the player can first front wall-run a wall, and then jump backwards, and keep wall-running and jumping. The player can get into a lot of places where you might first think they might not, and in some cases it has been difficult to naturally create maps where the player can't return to the previous area.

Looking for help

We are still looking for people. If you are interested to apply, you can send me a message on Moddb, Twitter, Facebook, or e-mail me at au-heppa@hlssmod.net.

Level Designers
We are looking for two different types of Level Designers. Firstly, we need people that can bring existing levels an aesthetic quality, and are experienced with lighting, texturing, and the general make up in Hammer. Screenshots and/or example maps are required.

We are also looking for puzzle designers, such as anyone who has a lot of experience designing different types of puzzles for games like Portal 2. Source engine or Hammer experience is not necessary.

Concept Artists
Most of the concept work will revolve around the industrial era Alien technology and architecture. Samples of previous work required. We already have a strong set of existing concept art for you to draw on.

Voice actors and actresses
Although the script is nowhere near ready, we are looking for people to play the parts of Zenaida, Anthony, as well as the generic voices of aliens, both male and female actors. All voice actors applying should provide some kind of samples. You should be able to do big range of emotions. Some lines might be delivered at a later date.

The aliens will be speaking an alien language specifically designed for this mod. Their dialogue is partly already written and ready for recording. Examples will be provided if you are interested.

We are interested on getting any help we can get, especially world texture creators and prop modellers.


I haven't seen this mod before this article was posted, but I gotta say, you've made some fantastic progress! The climbing and interaction with buttons and the world adds so much to the quality of your work! I'll be keeping an eye on you and your project for sure!

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said it before but will say it again.
LOVE the animations!!!!
specially now after having seen this new video about climbing etc,
really well made!!! Its clear that you are a very skilled animator.
I would love to help out with level design but i am very busy with my own
latest mod, would this not be the case then for sure i would offer my help. This is really something else!
For sure i will keep tracking your project.

much success,

Don't know if you are familiar with the Jobsection of Moddb, this is a place were you can place job adds for indie games but also for mods. You can find it under the "Jobs!" button at the top right site of modds page above. Its free and many people check there when they are looking for helping out mods.

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"Mirror's edge" in space? You seriously have my attention...

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Huge Mirror's Edge fan. Really looking forward to this project and keeping a close eye on it.

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Are you using the Alien Swarm base? - I kinda hope so, epic vgui and multicore rendering would really fit.

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Au-heppa Author

At the moment we are using Source SDK Base 2007.

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So amazing for the hl2 engine!!!! :)

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