|Penumbra: Black Plague - Developer Diary part 3|
|Posted: 23.01.2008 14:17 by Kres||Comments: 0|
Paradox Interactive released a third Developer Diary for their upcoming Horror adventure game, Penumbra Black Plague. In this Developer Diary Frictional games two man team talk about the physics being one of the main features for Penumbra Black Plague.
One of the main features in Penumbra: Black Plague is the physics. This is a feature that adds a lot of immersion and gives new opportunities for gameplay. However, it has not been without problems to implement it and that is what we will focus on in this diary entry. We will go through some of the different problems we encountered and explain how we solved them.
At the core of the physics in Penumbra: Black Plague there is an engine called Newton Game Dynamics. This engine makes sure objects collide and react realistically in the game world. But having the physics running is far from enough if you want to have an interactive game, there's a lot of work left to be done.
Our first challenge was to get the physics engine working with the game and the main thing in Penumbra is to be able to interact with objects. We wanted the interaction to be natural, simple and allow the player to intuitively understand the controls. However to get it all working we could not just slap on a generic system, instead we had to specialize every object in the world so that it reacts as you expect it to. First of all we have three different types of interaction that we use for each object: grab, push and move. Grabbing is used for objects that you simply pick up, push is used on larger objects that cannot be lifted and move is used on things like drawers, doors and levers. Once the type of object has been determined several properties needed to be tweaked. How much should the object weigh, is it slippery, should it be rotated along with the player and so on. All of these things needed to be tweaked carefully and the wanted behavior often changed depending on the situation.
This meant that a route the AI had picked out could be blocked at any time and become invalid. To solve this we made the AI constantly check if the path was clear and if it was not, have them update their paths to go around the obstacle. Also, the AI needed to have routines to see if a blocked path could perhaps be cleared (by pushing or kicking and breaking) instead of going around, which took a lot of tweaking to get right. In the end we had to tweak all world objects (again) and make sure that the AI would handle them correctly. Countless of hours have been put into checking so that the enemies behave intelligently in the many situations that can arise.
Using the physics to design puzzles
As mentioned above, a lot of work went into to setting the correct properties to various objects so that they reacted correctly in the world. This was especially true when designing and creating the puzzles in the game levels. We wanted to have as few inventory based puzzles as possible and instead have the player physically interacting as much as possible. Having this goal proved to require a lot of work to make sure that the puzzles where fun and worked as planned.
The best and worse thing with physics puzzles is that you can never plan for every event. There are endless of ways in which the physics can be used and this means that you can never be sure that you have tested every single way in which the player can approach a puzzle. The good thing with this is that the player can solve puzzles in ways, we as designers, never planned. The bad thing is that the puzzle might be broken in unexpected ways too. For example if you need to cross a rift using boards, it is hard to prevent the player from simply throwing down all the boards into the rift, making the puzzle unsolvable. During the development of the game we tried hard to minimize these sorts of things, however we also didn't want to be overprotective either. Because of this we made the decision to leave a way to destroy the puzzle, if it made the way to solve it the more open. As long as it was very obvious when the player destroyed a puzzle we figured this approach would be a lot better than holding a player’s hand every step of the way, making the game much more linear.
What we have just described is just a little part of all the obstacles we had with the physics, but hopefully it will give you a glimpse of the work we have put into getting them really good. Although the physics have been hard work, we believe that it has added a lot to the game and given it a unique feel and atmosphere. Hopefully all of you who play the game will think likewise!