Prototype Spell: Orbit Shield

posted in A Keyboard and the Truth for project 96 Mill
Published August 19, 2009
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Two videos (with slightly borked timestep from video frame drop)
showing a prototype for a spell in MW2 called Orbit shield, which picks up environmental debris and whips them around you at a fixed distance creating a ring of rotating matter that can both protect and harm enemies; me likey :)


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Comments

shadowcomplex
Hey EDI! It's been nice to read about your progress on MW2. A lot of things already look superior compared to the original.

The orbit spell conceptually is great -- who doesn't want a big vortex of debring protecting them from things that go bump in the night?? :D

The video was a bit dark for me, however, one aspect really stood out as unnatural. The orbiting paths of the debris weren't constantly smooth -- often they looked to follow a polygon shape around the character and sometimes even coming to dead points before making hard course changes. Perhaps this has to with the time step you mentioned? If not, I'd consider smoothing it out to be more circular/elliptical -- it currently breaks immersion.

From a gameplay standpoint: when the debris collide with something (say the environment or a nasty creature) will they go richocheting out of orbit? Or correct the path after reflection? Maybe this was apparent in the video, but I couldn't tell and am curious how you plan on handling that. It seems to me like a critical balancing point for the spell :)

Keep on showing off progress!!
August 19, 2009 03:21 PM
EDI
Quote:Original post by shadowcomplex
Hey EDI! It's been nice to read about your progress on MW2. A lot of things already look superior compared to the original.


Thanks :)

Quote:
The orbit spell conceptually is great -- who doesn't want a big vortex of debring protecting them from things that go bump in the night?? :D


That was my thought really; I was so excited to be dealing with actual physics, almost my first thought was to have a bunch of stuff orbiting around you as a shield.

Quote:
The video was a bit dark for me, however, one aspect really stood out as unnatural. The orbiting paths of the debris weren't constantly smooth -- often they looked to follow a polygon shape around the character and sometimes even coming to dead points before making hard course changes. Perhaps this has to with the time step you mentioned? If not, I'd consider smoothing it out to be more circular/elliptical -- it currently breaks immersion.


It's at least partially due to time step; the routine I use to orbit debris is actually quite simple:

- get all actors within a 256 pixel radius of you, omitting yourself and other special things
- measure the distance between yourself and each object
- calculate the deviation in distance between the object an the ideal orbit radius... (say 200) taking into account a +-32 pixel dead-band
- use that deviation along with mass to apply a force to the object to bring it into the dead-band
- if within the dead band, rotate the unit vector formed between the object and yourself 90 degrees, and use that to apply a force to rotate the objects around you.

I can surely say at 60 fps (which is currently where the timestep is happy) i can sit in a spot without any collisions and get a nice ring of objects flowing happily and smoothly.

Quote:
From a gameplay standpoint: when the debris collide with something (say the environment or a nasty creature) will they go richocheting out of orbit? Or correct the path after reflection? Maybe this was apparent in the video, but I couldn't tell and am curious how you plan on handling that. It seems to me like a critical balancing point for the spell :)

Keep on showing off progress!!



The answer is, it depends; the spell is based entirely on your envelope of influence, which is currently a 256 pixel radius; if an actor steps in your path properly it will get bombarded by the objects orbiting you
some of those objects are likely to be sucked up and accelerated again into orbit, some might go flying in another direction, it depends a lot on the angle, mass difference, if any rotation on the object is currently present; in short it's freeform which is what makes it so much fun.

August 20, 2009 08:15 AM
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