Creatures 3 Changes

New gene types

Facial expression genes
Similar to gait genes, these switch between different expressions in the sprite file according to what drive is most important in the creature at the time. Drives can be given weights to make sure that a little bit of pain makes a creature look hurt for example, whereas the creature has to be quite tired before it looks sleepy.

Like a cross between a neurone and an emitter. Up to four chemicals can be emitted off any neurone when it fires.

Brain tract
Allows a greater degree of flexibility in how and where dendrites connect from one lobe to another.

Alterations to existing genes

Gene headers - Variant.
A new box has been added to the header of each gene called 'variant'. This has been done to accommodate the Creatures Adventures genome system, where all eight behavioural types of Norn are coded for using the same genome (a bit like having male and female in one genome, but only expressing one or the other)

Extended list of stimuli to allow for wider range of behaviours

Can now alter reaction rates as well as organ clockrates

New (and improved) systems

Fear and pain overwhelmsion
This system (spread over three organs) acts to convert drives into 'backup drives' when levels of fear or pain get over a certain threshold. This effectively 'silences' all other drives apart from pain or fear, and removes them from the decision making process, so that a creature can concentrate on stopping the pain or getting out of trouble. It was thought that with new, more aggressive Grendels, that this would allow Norns to survive for a bit longer.

The first organ, the constitutive drive maintenance organ contains reactions that convert drive backup chemicals to drive chemicals. These reactions take place whenever there is any drive backup chemical present, but this only has an effect if the other two organs are not working against it. The other organs - the painly drive overwhelmsion organ and the fearly drive overwhelmsion organ, have receptors for pain and fear drive chemicals respectively. When these are detected, the clockrate of the organ is increased, and the drives are converted into drive backups. Although the maintenance organ then tries to convert them back, it can't succeed against the overwhelmsion organ, and so the drives 'go underground'. Once the levels of fear or pain drop below the detectable threshold, the maintenance organ quickly restores the drives to the level they were at before conversion.

Stress system -
This organ contains the stress system, which is turned on only in youth in all three creatures. It consists of a two-tier system of receptors and emitters attached to floating receptor-emitter loci, which allows the system to be slow (so the creature is not swamped with harmful stress chemical all the time if it forgets to eat for a while), flexible (it tracks all of the drives individually, and can respond to any change in each of the drives individually) and because it was more realistic than a simple 'high drive in - stress out' system. It works by using a separate receptor for each drive, setting a threshold for how high that drive is allowed to go before being likely to cause stress and discomfort, and then turning on a floating receptor-emitter pair. The corresponding emitter then slowly emits a chemical called Stress (drive) where the drive is the drive that caused all this to happen in the first place. This allows us to set different levels of drive for different species - so an Ettin gets more easily stressed by being crowded than a Grendel does for example.

Another tier of paired floating receptor-emitters picks up the presence of Stress (drive). Once a certain threshold of Stress (drive) has been detected by a receptor, it will turn on a second locus, from which Stress chemical itself will be emitted. This in turn will be detected by receptors in other organs, and cause slowing of some (immune system, reproductive system). One effect that we hope would come from this is the gradual improvement of Norns to become better at surviving on their own - those that can satisfy their drives well enough never to get stressed (or only slightly stressed) would breed better than those who were almost infertile due to stress damage.

Improved immunity
The bacterial infection system in the game has been entirely reworked to give more dynamic infections. Each bacterium is now an agent in its own right, with a defined (but mutable) infection level, uninfection level and a chance to mutate to alter the symptoms that a creature exhibits. Generally, each bacterium can infect a creature with one or more antigens as well as a toxin or two.

In addition to this, the toxins themselves were looked at, and a wider (and nastier) range of symptoms and effects were built in. These were also standardised across the three species, although you might notice that Ettins and Grendels have immunity to some of the diseases that Norns can catch! In order to make the immune systems more efficient, Vitamin C now increases the production rate of antibodies, so if you have a sick Norn get them to the medical bay quickly and have a look at what is going on inside them.

Improved reproduction
The reproductive cycle now puts much more emphasis on female fertility being high in order to mate. The regulatory chemicals are now used during pregnancy or after birth in females, and when no suitable mate is around (in males) to suppress sex drive and allow creatures time to explore their world without worrying about reproduction. Pregnant females have also developed the urge to return to the Norn pod from wherever they are on the ship, so that they can lay their eggs well away from marauding Grendels.

Greater degree of organisation of metabolism into organs
In C2, if you wanted to have a reaction with a rate that changed, it had to be in an organ that had a receptor for a certain chemical. This receptor would change the clockrate of the organ, and so by default the rate of the reaction. This caused problems in the early days of C3, when in an attempt to get a better regulated metabolism, Norns ended up with over thirty-two organs at one point, most of which had one or two reactions in them. At that point, it was decided to allow receptors to bind to reactions as well, and so alter the rate of a reaction directly (to act as an enzyme in other words). Doing this meant that diverse reactions could be grouped under the same organ, and so organs became more realistic in their function. The greatest changes from a c2 genome can probably be seen in the liver and digestive organs which now collect together such diverse tasks as assigning amino acid to muscle tissue, breakdown of fat into fatty acid, manufacture of cholesterol - each reaction under individual regulation by an enzyme/receptor.

Flight and fight
This system is based on smell concentrations. If a lone Norn can smell a Grendel, then a feeling of fear begins to build up inside him. Meantime, the Grendel, smelling the Norn, is getting angry - he hates Norns. If they encounter each other while in this mood, then there will be a short fight and hopefully the Norn will run away. However, if the Grendel comes marching over to a Norn, and then discovers that the Norn is not alone, but backed up by other Norns, things change. Instead of Grendel smell overpowering Norn smell, the opposite is true, and the Grendel begins to experience fear, while the Norns become angry. There may even be a fight, with the Grendel being forced to retreat

The system is small and very simple, with fear and anger being amplified by adrenaline. A receptor for Norn or Grendel smell alters the rate of a reaction in the creature to convert fear into anger or vice versa. In a Norn, if the Grendel smell outweighs the Norn smell, then the reaction converting anger to fear goes fastest, while in a Grendel, any fear would be converted into anger. Swap the smell concentrations around, and the Norns become angry and the Grendel scared. The system is delicately balanced to allow an element of chance to decide the outcome of any encounter.

Working pigment system
The pigmentation system implemented in C2 creatures has been overhauled and now works very well.

Improved behaviour
Goes without saying!

Other changes
Reorganised chemical list -

The old chemical list was looking a bit tatty round the edges, so it was taken, scrubbed and totally reorganised. We removed a few chemicals that were not going to be used, and then the rest of the list was organised with all the chemicals in logical groups - all the general reproductive chemicals together, and all the immune system chemicals somewhere else and so on. A couple of slots were left between each such group to allow some space for expansion, and it also left a healthy chunk of free spaces at the end of the list.

The only fly in this ointment was a final culling of all chemicals that were not used just before the release of C3, which did leave some gaps, but in general it should be much easier to find chemical than it used to.
There are a few new categories of chemical - chemicals that track the smell gradients that waft around the room systems and allow creatures to navigate (CA smell chemicals), some chemicals that are specific to the brain, and act as sort-of-drives to help navigation, a few new toxins, the drive backup chemicals, new stress chemicals and of course a few changes to the drives that motivate creature behaviour, and there may be a few that you miss as well, so it is worth looking at the chemical list and the explanations before leaping into the laboratory

Altered list of drives
The list of drives that you will find inside a creature has changed considerably since C2. There seemed to be some overlap between 'need for pleasure' and 'boredom' so these were combined to 'boredom'. Creatures don't seem to need liquid as much as was originally thought, so 'thirst' was also removed.

Most of the other drives were left alone in the end, as they all relate to simple behaviours (sleeping, being scared) and seemed to work quite well prompting creatures to do something. The only other big change was to split the hunger drive up into three separate drives, each needing a different chemical to satisfy them. This, it was hoped, would lead to creatures being a bit more active when they searched for food, as they would have to find three types of food to stop being hungry, and made ignoring any food much more dangerous to health. It also allowed the biochemistry to become a little more complicated, as creatures now not only had to be able to digest and use amino acids, sugars and fats, but had been given the means to find each food type specifically.

The creatures in C3 have a navigation system based on their sense of smell, and several chemicals were added in order to accomplish this. They are drives in one sense, as they prompt a creature to do something, and have actions that a creature can perform to lower them (going through a door or returning home for example), but as they are seen only by the brain and used to navigate rather than interact with the world, they ended up being called 'brain chemicals'. The exception to this is 'Comfort drive' which was added ahead of the others during development, and nudges a creature into heading home when levels get high. This 'homing instinct' was used to send pregnant creatures trudging towards their homes to lay eggs and also to help the Ettins take their stolen gadgets home.

New Stimuli
The list of available stimuli (the messages sent to a creature's brain when it has done something like eaten, walked into a wall, mated, sneezed and so on) was extended to allow for more complex behaviours and a wider range of actions.

Floating point
The entire biochemistry, engine, brain and even the plants in the office here at Creature Labs went over to a floating point system because 'It's faster, cooler and more accurate'.