Breakable objects - Revision history

Tels: fix name of spawnargs

2008-02-11T19:32:59Z

fix name of spawnargs

← Older revision		Revision as of 19:32, 11 February 2008
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	The [[broken]] sets the model that will replace the default model after the destruction. The entity itself will stay around, but it cannot be damaged any further.		The [[broken]] sets the model that will replace the default model after the destruction. The entity itself will stay around, but it cannot be damaged any further.

	=== ~~[[def_broken]], [[broken_offset]], [[broken_probability]] and [[broken_count]] ===~~		=== def_flinder, flinder_offset, flinder_probability and flinder_count ===

	~~'''TODO''': Rename these to [[~~def_flinder]], [[flinder_offset]], [[flinder_probability]] and [[flinder_count~~]].~~

	Setting:		Setting:

	"~~def_broken~~" "models/darkmod/junk/wbottle01_broken.lwo"		"def_flinder" "models/darkmod/junk/wbottle01_broken.lwo"
	"~~broken_offset~~" "0 0 -5"		"flinder_offset" "0 0 -5"
	"~~def_broken1~~" "models/darkmod/junk/glass_shard.lwo"		"def_flinder1" "models/darkmod/junk/glass_shard.lwo"
	"~~broken_count1~~" "6"		"flinder_count1" "6"

	will result in the bottle spawn one broken lower half bottle, and 6 glass shards. The original entity will be removed from the world automatically.		will result in the bottle spawn one broken lower half bottle, and 6 glass shards. The original entity will be removed from the world automatically.

	''~~broken_offset~~'', ''~~broken_probability~~'' and ''~~broken_count~~'' are optional.		''flinder_offset'', ''flinder_probability'' and ''flinder_count'' are optional.

	== Todo ==		== Todo ==

Tels: fixup

2008-02-10T23:37:49Z

fixup

← Older revision		Revision as of 23:37, 10 February 2008
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	For breaking the connection between bound objects, please see the article about [[breakable bonds]].		For breaking the connection between bound objects, please see the article about [[breakable bonds]].

	== ~~Destroying~~ Objects ==		== How to Destroy Objects ==

	When the force acting on one entity becomes very strong, it should be destroyed. This can happen while the entity is still bound to another entity, or after they have become unbound.		When the force acting on one entity becomes very strong, it should be destroyed. This can happen while the entity is still bound to another entity, or after they have become unbound.

	Currently, there are ~~three~~ ways to denote that an entity should be destroyed/broken upon ''death'':		Currently, there are two ways to denote that an entity should be destroyed/broken upon ''death'':

	=== Setting [[health]] ===		=== Setting [[health]] ===

Tels: fix typo

2008-02-10T23:23:15Z

fix typo

← Older revision		Revision as of 23:23, 10 February 2008
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	Setting:		Setting:

	"~~def_spawn~~" "models/darkmod/junk/wbottle01_broken.lwo"		"def_broken" "models/darkmod/junk/wbottle01_broken.lwo"
	"broken_offset" "0 0 -5"		"broken_offset" "0 0 -5"
	"def_broken1" "models/darkmod/junk/glass_shard.lwo"		"def_broken1" "models/darkmod/junk/glass_shard.lwo"

Tels: fix spawnarg names

2008-02-10T23:22:20Z

fix spawnarg names

← Older revision		Revision as of 23:22, 10 February 2008
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	The [[broken]] sets the model that will replace the default model after the destruction. The entity itself will stay around, but it cannot be damaged any further.		The [[broken]] sets the model that will replace the default model after the destruction. The entity itself will stay around, but it cannot be damaged any further.

	=== [[~~broken_spawn~~]], [[~~broken_spawn_offset~~]] and [[~~broken_spawn_count~~]] ===		=== [[def_broken]], [[broken_offset]], [[broken_probability]] and [[broken_count]] ===

			'''TODO''': Rename these to [[def_flinder]], [[flinder_offset]], [[flinder_probability]] and [[flinder_count]].

	Setting:		Setting:

	"~~broken_spawn~~" "models/darkmod/junk/wbottle01_broken.lwo"		"def_spawn" "models/darkmod/junk/wbottle01_broken.lwo"
	"~~broken_spawn_offset~~" "0 0 -5"		"broken_offset" "0 0 -5"
	"~~broken_spawn1~~" "models/darkmod/junk/glass_shard.lwo"		"def_broken1" "models/darkmod/junk/glass_shard.lwo"
	"~~broken_spawn1_count~~" "6"		"broken_count1" "6"

	will result in the bottle spawn one broken lower half bottle, and 6 glass shards. The original entity will be removed from the world automatically.		will result in the bottle spawn one broken lower half bottle, and 6 glass shards. The original entity will be removed from the world automatically.

	~~Both~~ ''~~broken_spawn_offset~~'' and ''~~broken_spawn_count~~'' are optional.		''broken_offset'', ''broken_probability'' and ''broken_count'' are optional.

	== Todo ==		== Todo ==

Tels: update

2008-02-08T15:29:13Z

update

@@ Line 11: / Line 11: @@
 == Destroying Objects ==
-When the force acting on one entity becomes very strong, it should be destroyed. This can happen while the entity is still bound to another entity, or after they have become unbound. These cases are already working for some objects, like wine bottles.
+When the force acting on one entity becomes very strong, it should be destroyed. This can happen while the entity is still bound to another entity, or after they have become unbound.
-Currently, this is done by setting the following [[:Category:spawnargs|spawnargs]] on one entity:
+Currently, there are three ways to denote that an entity should be destroyed/broken upon ''death'':
          "health"                        "20"
-The [[Spawnarg:health]] sets the amount of damage that needs to be done to the object until it breaks, and the
+the entity will be destroyed when the health drops to 0.
-[[Spawnarg:broken]] sets the model that will replace the default model after the destruction.
 Drawbacks of this method are that health can drop by small forces acting on the entity. After the health has dropped considerable, a small force can then suddenly break the object. For instance, damaging a wine bottle by 9 points 2 times would leave the bottle with only 2 points health, and thus suddenly a damage of 2 points can destroy the bottle.
 Another drawback is that forces do not translate into damage except in some specially coded exceptions, like hits from weapons or movers that ''damage'' entities.
 {{important|headline=TODO|text=

Tels: move content of breakable bonds to sep. article

2008-02-08T13:12:22Z

move content of breakable bonds to sep. article

Show changes

Tels: add torque and compression force

2008-02-01T16:09:03Z

add torque and compression force

← Older revision		Revision as of 16:09, 1 February 2008
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	{{clear}}		{{clear}}

			=== Torque ===

			Forces acting on a joint also create torsion. If the torsion is bigger than a certain amount, the bind should also break up. This simulates shearing off the bound entity.

			[[Image:Compression force.png\|200px\|right]]

			=== Compression ===

			When the force acting on the joint lies actually in the direction of the binding force, the bond would not break up, as the acting force will just reinforce the joint. However, in reality there is a limit on how much force the connection can carry, and this is more or less related to the strength of the component carrying the load. In the image to the right, the compression force is acting on the part between the ground and the upper part.

			{{clear}}

			{{important\|headline=TODO\|text=
			* Define a maximum force that the part can carry, before it gets destroyed.}}

	=== Pivotpoints/Joints ===		=== Pivotpoints/Joints ===

Tels: add relaying impulses forward/backward

2008-02-01T15:26:33Z

add relaying impulses forward/backward

← Older revision		Revision as of 15:26, 1 February 2008
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	{{important\|headline=TODO\|text=		{{important\|headline=TODO\|text=
	Currently, the impulse is always relayed to the '''single''' bind master.		Currently, the impulse is always relayed to the '''single''' bind master.
			}}

			The incoming forces/impulses need also be relayed '''back''' from the bind master to the bind slave.

			{{important\|headline=TODO\|text=
			Currently, the impulse is only relayed in one direction.
	}}		}}

Tels: add multiple joints

2008-02-01T15:24:21Z

add multiple joints

← Older revision		Revision as of 15:24, 1 February 2008
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	Drawbacks of this method are that health can drop by small forces acting on the entity. After the health has dropped considerable, a small force can then suddenly break the object. For instance, damaging a wine bottle by 9 points 2 times would leave the bottle with only 2 points health, and thus suddenly a damage of 2 points can destroy the bottle.		Drawbacks of this method are that health can drop by small forces acting on the entity. After the health has dropped considerable, a small force can then suddenly break the object. For instance, damaging a wine bottle by 9 points 2 times would leave the bottle with only 2 points health, and thus suddenly a damage of 2 points can destroy the bottle.

	Another drawback is that forces do not translate into damage except in some specially coded exceptions, like hits from weapons.		Another drawback is that forces do not translate into damage except in some specially coded exceptions, like hits from weapons or movers that ''damage'' entities.

	{{important\|headline=TODO\|text=		{{important\|headline=TODO\|text=
	* Except wine bottles, no object breaks when a sufficient force acts on it.		* Except wine bottles, no object breaks when a sufficient force acts on it.
	* Strong forces do not nec. damage entities. For instance dropping a crate on a bottle does not break the bottle.}}		* Strong forces do not nec. damage entities. For instance dropping a crate on a bottle does not break the bottle.
			* Damage needs to be calculated from the impulse, not from a fixed set of "damage" values.}}

	== Breaking Bonds (Unbinding) ==		== Breaking Bonds (Unbinding) ==
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	{{clear}}		{{clear}}

			=== Multiple joints ===

			It is not enough to have one possible bind/joint per object, as the following graphic shows:

			[[Image:Pivot_point_counts.png\|center]]

			{{clear}}

			In the first case on the left, there are four objects and four joints, such that each object can be bound to exactly on other object.

			But by adding one more object, we need now more joints than we have objects, making it nec. that at least one object has more than one bind-partner.

			=== Relaying forces ===

			Forces/impulses acting on one object need to relayed to each bind partner, through the pivot points. At this point the force needs to be dampened (to simulate stiff joints and friction).

			{{important\|headline=TODO\|text=
			Currently, the impulse is always relayed to the '''single''' bind master.
			}}

	=== Sumary ===		=== Sumary ===

Tels: add info aboit pivotpoints

2008-02-01T14:08:21Z

add info aboit pivotpoints

← Older revision		Revision as of 14:08, 1 February 2008
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	This article deals with details in regarding of breakable objects in the physics simulation.		This article deals with details in regarding of breakable objects in the physics simulation.

	=== Destroying Objects ===		== Destroying Objects ==

	When the force acting on one entity becomes very strong, it should be destroyed. This can happen while the entity is still bound to another entity, or after they have become unbound. These cases are already working for some objects, like wine bottles.		When the force acting on one entity becomes very strong, it should be destroyed. This can happen while the entity is still bound to another entity, or after they have become unbound. These cases are already working for some objects, like wine bottles.
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	* Strong forces do not nec. damage entities. For instance dropping a crate on a bottle does not break the bottle.}}		* Strong forces do not nec. damage entities. For instance dropping a crate on a bottle does not break the bottle.}}

	=== Unbinding ===		== Breaking Bonds (Unbinding) ==

	[[Image:Bind entities.png\|right]]		[[Image:Bind entities.png\|right]]
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	{{important\|headline=TODO\|text=This is currently never the case.}}		{{important\|headline=TODO\|text=This is currently never the case.}}

	==== Forces acting on bound entities ====		=== Forces acting on bound entities ===

	To simplify the explanations, we consider here only 2D-forces. The third dimension can then be easily added by using an impulse 3D vector.		To simplify the explanations, we consider here only 2D-forces. The third dimension can then be easily added by using an impulse 3D vector.
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	{{clear}}		{{clear}}

	==== Attachment Strength ====		=== Attachment Strength ===

	[[Image:Attachment strength.png\|right\|320px]]		[[Image:Attachment strength.png\|right\|320px]]
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	{{clear}}		{{clear}}

	The force that binds two objects does not only depend on the mass (due to gravity), but on the size of the contact face, and on the strength of the contact (consider glue vs. nails):		[[Image:Contact face.png\|320px\|right]]

			The force that binds two objects does not only depend on the mass (due to gravity), but on the size of the contact face, and on the strength of the contact (consider glue vs. nails). We simulate this by setting different <code>bind_force</code> arguments for each joint:

			{{clear}}

	[[Image:~~Contact~~ face.png\|~~320px~~\|right]]		=== Pivotpoints/Joints ===

			[[Image:Pivot_point_automatic.png\|320px\|right]]

			The ''bind_force'' applies at a certain point, the pivot point. Here is an example showing different situations and the different pivot points:

			In these cases it would be possible to automatically calculate the position of the pivot point, namely if the bind slave and the bind master have one common contact face.

			{{clear}}


			[[Image:Pivot_point_manual.png\|400px\|right]]

			However, in the following cases there is either no contact face (the entities are not touching each other) or
			more than one contact face. This means the pivot point would have to be set manually:

	{{clear}}		{{clear}}

	==== Sumary ====		=== Sumary ===

	To evaluate whether two bound objects should separate, we need to consider the following forces:		To evaluate whether two bound objects should separate, we need to consider the following forces: