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Collisoin
Topic Started: Mar 24 2009, 01:06 AM (1,187 Views)
saijee
Elite Member
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Did they use elliptical collision(with environment) in games like:
Mario 64: http://www.youtube.com/watch?v=DgHMObCvcYg
Zelda OoT: http://www.youtube.com/watch?v=GqYY5iAGxTo&feature=channel_page
Paper Mario: http://www.youtube.com/watch?v=-4WE4FSsISI&feature=related
Armored Core: http://www.youtube.com/watch?v=6SWio7yMmLU

I'm not entirely sure, though it seems more like a collision 'cylinder' then an elliptical. Though it does seem that the collision with environment in all the examples is done in a similar way. To get an effect like it would it be good to use elliptical collision? Why or why not?
Edited by saijee, Mar 24 2009, 01:07 AM.
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Satyr
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I really have to prefer collision cylinders, because of the fact that if you fall off a ledge you fall off, not get stuck on the side, while continuing to have the smooth wall collisions of a sphere. imo btw
The feeling of homesickness never goes away when you return to your parents home from years of being away.

same goes with the smell of ash and smoke from the day you set it ablaze.
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Despellanion
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It was a very long time since I played Ocarina of Time but as I remember it, the wall collisions where pretty smooth. I think Mario64 and Zelda used the same collision system. I would guess it was either spherical or cylindrical collision detection. Simple ray tracing would have made the collision more choppy and inacurate.
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saijee
Elite Member
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I feel it was more like a cylinder because I remember that if you stepped on a corner, you never slid off like you would in u3d's sphere...

Though how do you think you would do a collision cylinder?

One thing I was thinking of doing is having a system of rays...

One pointing strait up, one pointing strait down, and two pointing in a direction the object wants to move in (is facing) the latatude would be based on the direction your facing, but the longitude of the rays would depend on the direction the face your standing on is facing...

Though I have never tested this...
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skarik
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kitten eating scum
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No rays. Better way. Make a sphere really flat and then make it go from head of start position to toe of end position. Not exactly a cylinder, but gives the same effect. New version of Stickman does it.
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saijee
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'No rays' err do you mind explaining to me why not? (Keep in mind I'm new to u3d's collision stuff, for the past whatever, I have only been using it to simply display the graphics.)

Anyway, your idea seems cylinder enough to me.... Do you know the easiest way to get a general representation of where (what space it is occupying) the cyntricoid is?
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saijee
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Umm, hello? I want to know...
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zeo
I like turtles.
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No need to spam this forum mate, there is very few active members and it takes time to get the needed reply.



Anyway, I made this drawing, basicly explaining what Skarik is referring too:
Posted Image

49 46 20 59 4F 55 20 43 41 4E 20 52 45 41 44 20 54 48 49 53 20 59 4F 55 20 52 45 41 4C 4C 59 20 4E 45 45 44 20 54 4F 20 47 45 54 20 4C 41 49 44 3A 29
recur-recur-recur-recur-recursion-sion-sion-sion-STACK OVERFLOW
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saijee
Elite Member
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Actually it's a bump not spam.

Thanks for replaying but that but that did not answer my questions, and I could already understand that part. But I wanted to know why 'not to use ray tracing' and what an easy way to draw the cylindraptoid would be.


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skarik
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kitten eating scum
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1. You don't use ray tracing for a few reasons. Mainly, if you're doing more than one ray, it takes much more GM-side calculations than an automated swept ellipsoid does. If you do just one ray, it isn't precise enough. If you were standing on top of tight rope in your game, it would be impossible to stay on it unless you give the computer control. Even then, it's iffy. To solve this, you would cast more rays downward. However, the number of calls to U3D increases like crazy in this case. If you let the ray casting approach a high number, you basically get a cylinder check. Why not just do it all in one function call?

2. Give a moment. I've gotta draw a picture.
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skarik
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kitten eating scum
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2. Here's the explanation:

Posted Image
Attached to this post:
Attachments: Collision_Explanation.png (7.98 KB)
Edited by skarik, Mar 28 2009, 09:13 PM.
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saijee
Elite Member
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Ok skarik, so multi rays uses more processing power then a swept ellipsoid.

As for the picture, maybe I was not clear, but by 'draw the cylinder I meant in the game... I can tell what it would look like on a diagram just by thinking of it, but I want to know how I would draw out a representation of where the cylinder is as a shape in the game for debug purposes... You know? Just to make sure it's doing what it is supposed to.
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skarik
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kitten eating scum
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On drawing it, I have no idea. You could always draw the rays. XD
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saijee
Elite Member
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Would it be best just to make a *.3ds of a cylinder that is the same size and shape as what it is supposed to be in the game, then have an object that draws this cylinder and make it always track the characters?
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skarik
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kitten eating scum
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Probably.
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