cortex: thesis/cortex.org comparison

comparison thesis/cortex.org @ 464:8bf4bb02ed05

sleeeeeep.

author	Robert McIntyre <rlm@mit.edu>
date	Fri, 28 Mar 2014 00:42:42 -0400
parents	6d55ac73bc6f
children	e4104ce9105c

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-:6d55ac73bc6f
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 screengraphs to avoid drawing things that do not appear on the
 screen. It has an active community and several games in the
 pipeline. The engine was not built to serve any particular
 game but is instead meant to be used for any 3D game.
 I chose jMonkeyEngine3 because it because it had the most features
-out of all the open projects I looked at, and because I could then
+out of all the free projects I looked at, and because I could then
 write my code in clojure, an implementation of =LISP= that runs on
 the JVM.
 ** Bodies are composed of segments connected by joints
+For the simple worm-like creatures I will use later on in this
+thesis, I could define a simple API in =CORTEX= that would allow
+one to create boxes, spheres, etc., and leave that API as the sole
+way to create creatures. However, for =CORTEX= to truly be useful
+for other projects, it needs to have a way to construct complicated
+creatures. If possible, it would be nice to leverage work that has
+already been done by the community of 3D modelers, or at least
+enable people who are talented at moedling but not programming to
+design =CORTEX= creatures.
+Therefore, I use Blender, a free 3D modeling program, as the main
+way to create creatures in =CORTEX=. However, the creatures modeled
+in Blender must also be simple to simulate in jMonkeyEngine3's game
+engine, and must also be easy to rig with =CORTEX='s senses.
+While trying to find a good compromise for body-design, one option
+I ultimately rejected is to use blender's [[http://wiki.blender.org/index.php/Doc:2.6/Manual/Rigging/Armatures][armature]] system. The idea
+would have been to define a mesh which describes the creature's
+entire body. To this you add an skeleton which deforms this
+mesh. This technique is used extensively to model humans and create
+realistic animations. It is hard to use for my purposes because it
+is difficult to update the creature's Physics Collision Mesh in
+tandem with its Geometric Mesh under the influence of the
+armature. Without this the creature will not be able to grab things
+in its environment, and it won't be able to tell where its physical
+body is by using its eyes. Also, armatures do not specify any
+rotational limits for a joint, making it hard to model elbows,
+shoulders, etc.
+Instead of using the human-like ``deformable bag of bones''
+approach, I decided to base my body plans on multiple solid objects
+that are connected by joints, inspired by the robot =EVE= from the
+movie WALL-E.
+#+caption: =EVE= from the movie WALL-E.  This body plan turns
+#+caption: out to be much better suited to my purposes than a more
+#+caption: human-like one.
+[[./images/Eve.jpg]]
+=EVE='s body is composed of several rigid components that are held
+together by invisible joint constraints. This is what I mean by
+``eve-like''. The main reason that I use eve-style bodies is for
+efficiency, and so that there will be correspondence between the
+AI's vision and the physical presence of its body. Each individual
+section is simulated by a separate rigid body that corresponds
+exactly with its visual representation and does not change.
+Sections are connected by invisible joints that are well supported
+in jMonkeyEngine3. Bullet, the physics backend for jMonkeyEngine3,
+can efficiently simulate hundreds of rigid bodies connected by
+joints. Sections do not have to stay as one piece forever; they can
+be dynamically replaced with multiple sections to simulate
+splitting in two. This could be used to simulate retractable claws
+or =EVE='s hands, which are able to coalesce into one object in the
+movie.
 ** Eyes reuse standard video game components
 ** Hearing is hard; =CORTEX= does it right

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comparison thesis/cortex.org @ 464:8bf4bb02ed05