hit cylinder

bamb · Post by **bamb** » 31 Jul 2006, 12:15

instead of a sphere. It would be useful for tall structures like laser towers. And computationally actually more efficient. Rotations in z-axis wouldn't change it at all, and structures can't be tilted in spring, can they? So it would be rotation-stable, just like a sphere.
For buildings only of course.

Das Bruce · Post by **Das Bruce** » 31 Jul 2006, 12:18

Non rotating hit boxes are currently in use arn't they?

Post by **jcnossen** » 31 Jul 2006, 12:26

This is an implementation detail. If hit cylinders were such a good idea, SJ, or whoever wrote that, would have chosen cylinders.

TradeMark · Post by **TradeMark** » 31 Jul 2006, 12:28

Yeah good idea, i hate the spheres on small units, they take too much space :/

Das Bruce · Post by **Das Bruce** » 31 Jul 2006, 12:28

jcnossen wrote:This is an implementation detail. If hit cylinders were such a good idea, SJ, or whoever wrote that, would have chosen cylinders.

Not exactly, it might've been easier to do one than the other. Our footprints still don't rotate btw.

bamb · Post by **bamb** » 31 Jul 2006, 13:15

jcnossen wrote:This is an implementation detail. If hit cylinders were such a good idea, SJ, or whoever wrote that, would have chosen cylinders.

Of course I meant as a choice, in addition to spheres. Tall skinny structures don't really like those speres much, but a cylinder would fit there quite nicely. Just a niche solution really.
Maybe for really wide and low buildings too. (Air repair pad?) I don't know if it could be a tag somehow and automatically adjusted or if it's a part of the model file etc..

Caydr · Post by **Caydr** » 31 Jul 2006, 13:55

Would be useful as an option for modders.

Warlord Zsinj · Post by **Warlord Zsinj** » 31 Jul 2006, 14:37

We've been campaigning for better collision detection for a long time, as it is the cause of many issues in our mod, and the #1 prevention of the Star Wars in Space mod from getting off the ground.

We've come to the conclusion that it's unlikely to happen any time soon.

Pxtl · Post by **Pxtl** » 31 Jul 2006, 17:47

Most games use cylinders anyways. Almost every FPS and many other kinds of games use cylinders because it matches well to a humanoid form, square-based tanks, and the like. The few games I've seen that use spheres generally use 1 sphere per part (like the earlier Mechwarrior games) so that you can assemble a complex hitbox out of many simple hitspheres.

Caydr · Post by **Caydr** » 31 Jul 2006, 20:05

One sphere per object would kick colossal ass.

Acidd_UK · Post by **Acidd_UK** » 31 Jul 2006, 20:18

Edit: Somehow posted reply in the wrong thread. Ignore this..

FizWizz · Post by **FizWizz** » 31 Jul 2006, 21:00

What about for units that have a long, narrow geometry? Take something like the F-104 Starfighter for example. Hit cylinders would suck unless they could be oriented differently (although they would be an improvement on spheres). I would like to see collision boxes or meshes (ftw) implemented instead, but I guess cylinders are better than spheres for now.

Drone_Fragger · Post by **Drone_Fragger** » 31 Jul 2006, 21:17

or, howabout model defined hitboxes so you can easily make it whatever you want with minimal fuss?

FizWizz · Post by **FizWizz** » 31 Jul 2006, 21:25

that's what I meant to say when I said 'meshes.'
+1

FireCrack · Post by **FireCrack** » 01 Aug 2006, 00:17

^meshes can be quite slow, but a simple primative (sphere, cylender, cube...) or collection of simple primatives would work nicely for all but the biggest objects, the main problem with non spherical/cylindrical hit boxes is deciding what to do if the unit needs to turn and somthing is blocking it form doing so...

Pxtl · Post by **Pxtl** » 01 Aug 2006, 04:14

FireCrack wrote:^meshes can be quite slow, but a simple primative (sphere, cylender, cube...) or collection of simple primatives would work nicely for all but the biggest objects, the main problem with non spherical/cylindrical hit boxes is deciding what to do if the unit needs to turn and somthing is blocking it form doing so...

Hitspheres aren't used for unit-unit collisions anyways, afaik - only projectile ones, so we're good there.

FireCrack · Post by **FireCrack** » 01 Aug 2006, 08:54

That's excelent...

But what is used for unit-unit colossion then?

Warlord Zsinj · Post by **Warlord Zsinj** » 01 Aug 2006, 16:19

In terms of implementation, I think multiple spheres per model to mimick complex hit detection would probably be an easier option...

SinbadEV · Post by **SinbadEV** » 01 Aug 2006, 16:43

I believe for buildings it is a groudplate/footprint check, but I'm pretty sure everything else still used collision spheres.

bamb · Post by **bamb** » 01 Aug 2006, 16:43

nononono, why vertical cylinders are good that they don't care about rotation in the z axis! So you never have to transform (=rotate) them at all! I don't propose anything else.

They're as good as spheres. You never have to rotate speres since, well, they look the same anyway. That's why it's computationally efficient to have your peewee or llt in a sphere. If you had some box or so, it'd suck since you'd have to check the orientation of the unit and then rotate the box accordingly before checking hits. => expensive (you'd calculate some trigonometry)!. But vertical cylinder and sphere are the only forms that are z-axis-rotation independent.

A vertical cylinder has all the benefits of the sphere in a non-tilting unit (=building) and gives some extra accuracy.

You of course could have a box for a building too.

With units, you're still stuck to spheres since units rotate in all axes. You'd need trigonometry if you used boxes or cylinders. Ilmtitan proposed ellipses or oblong spheres, which is only slightly more expensive than spheres, but I dunno. You'd need the unit rotations too besides position to calculate hits, so amount of data would grow too.

Spring RTS Engine

hit cylinder

hit cylinder