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| We can now look at the Dynism's ability to Act which, apart from the Output Patterns we saw earlier, I've really said little about. |  |
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Unlike their weightless swimming predecessors, land-going Dynisms will usually need to keep many of their effectors in a constant state of operation just to maintain static configurations, like this basic four-footed stance, against the full force of PereGaean gravity. Their Joints must therefore each acquire Reflex Loops that will allow them to maintain their angular positions against all but the strongest forces. We'll call these Reflexes `Static Reflexes'. If a joint can rotate in two axes it will contain two such Static Reflexes, if it can rotate in three it will contain three. |
| A Dynism must obviously however be able to change its joint angles when necessary so that it can move its components in order to perform its necessary tasks like pursue Prey and avoid Predators. |
| However, instead of using Output Patterns to control the Effectors directly, let's suppose Dynisms now `alter the settings' for the angular positions at which the Static Reflexes maintain the skeletal joints using the same Model Maps we saw in the last chapter, plus any additional ones it may need. |  |
| These Reflexes themselves will then move the components to their new positions and hold them there so that the Dynism adopts a new configuration. Then, as we saw when we looked at Actions, when these Model Maps are executed in a Sequence with sufficient speed, the inertia and momentum of the components involved turn these `rigid' models into the smooth, even rhythmic motions required for such Actions as Walking, Swimming, Climbing, or Running. |
| Certain Models cannot however be performed directly after others. For instance when the Dynism extends its front leg, resuming the `stand' Model when stimulated to do so poses no problems. However, should it instead be stimulated, by an internal sensor perhaps, to lie down from that Model, it will need to resume its Stand Model, then perhaps sit down using its hind legs, then lower itself the rest of the way using its front legs. This means that to move from the first Model to the last, it must pass through two `intermediate' Models on the way. |
| The Dynism's Output Sequences must therefore be stored in a different way from its Input Sequences. Indeed, they are stored more like Maps, which contain the `links' of Intermediate Sequences it must perform in order to move from one `end' Model to the next. Here I've used square symbols to represent Start or End Models, round ones to represent Intermediate Models, and diamonds to represent Link Models from which more than one Sequence can be reached. Many Models, the Stand or Sit ones especially, will allow the Dynism to perform various minor Models simultaneously such as reaching out from a Stance, or closing its Jaws to seize a Prey. |  |
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This drawing shows the actual Models the Dynism would perform at each stage in the central portion of the above Map: |
| Here too `Speed Numbers' may be attached to a Sequence to control the speed at which it is executed. The faster an Action is performed however, the fewer any Modifying Sequences that can be executed simultaneously with it. Running quickly may well only allow gentle turns for instance. In some cases, especially with very brief Actions, the force required to execute them may be more important than their actual completion, the Denarian equivalent of a kick in self-defense perhaps. |
| More advanced Dynisms evolve new `Target Models' to alter the configuration of certain Subcomponents, a hand or foot for instance. These Models are quite separate from the whole-body configuration Models we've just seen, and may be of different sizes for each Subcomponent. |
| They allow the Dynism to acquire its first crude `Targeting Reflexes', as we'll call them. When the Dynism perceives an object that it is stimulated to contact or grasp in some way, it can use a Target Model to place the fingers or toes of a hand or foot close to the object's surface in the optimum configuration for such objects. The Static Reflexes can then continue the movement until contact with the object is made. |  |
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A Dynism does not always need to be able to see a surface to touch it. It can use touch sensors in its Components to feel around or behind an object to probe for Prey or to grasp the object itself. |
| To aid in the location of surfaces relative to its Target Models, the Dynism now acquires Stereoscopic Vision, if it hasn't already done so. Two eyes set some optimal distance apart insert their Stimulus Images into two Image Buffers. Their positions within these Buffers will differ from each other by a factor that depends on distance; The closer the object is, the greater this factor will be, the more distant the lesser. A Distance Tester can then use this factor to derive the object's distance and size. |
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Stereoscopic Vision now also helps slightly more advanced Dynisms to determine some aspects of a RAM Object's three-dimensional shape as well. For instance, it may now be able to determine whether a surface is `flat' enough to step on without slipping. |
| Target Models are also useful to the Dynism in another way. Let's imagine that the Dynism is walking from an area of flat ground towards ground that becomes increasingly broken until it becomes strewn with sizable rocks. |
Once these Rocks exceed a certain minimum size, the Dynism substitutes a Stepping Action for the Walk Action. This is like a Walk Action except that each of its front feet now has to be positioned using its Target Model towards the nearest surface of sufficient size and `flatness' that it can be safely stepped on.
The Dynism also uses its Body Model to ensure the Step Action places its rear feet onto exactly the same Safe Surface as its front feet when it moves forward one body length.
But the point will inevitably be reached where such Safe Surfaces are too far apart for Step Actions; the Dynism can progress no further.
If however the broken surface is followed by a relatively flat one, the Dynism may be able to select one or another `Jump Action' which involves moving its entire body in a single Action. Since this `Safe Surface' will lie partly or completely outside its Body Model, the Dynism must acquire a Tester which determines whether it is large enough to take all four of the Dynism's feet and contains enough empty space to accommodate its body. The Surface must also not be too far away horizontally or vertically, and there must be no intervening obstacles.
We will look at how the Dynism might come to make such `Decisions' later on, in the meantime we will assume it makes them entirely at random.
