KActor Touch problem

[Jereak]

Hello everyone !
I almost find every answer I need here (very nice forum !), but now there is an exception. Even with hours and hours of research, I can't find the solution to my problems, and that's really frustrating !

I work on a game where the player can control a ball. This ball is a KActor and normal collisions (with the world) work well, the ball can roll and move as expected. However I have some problems, particularly about "Touch" detection for the ball.

For example, if I have a TriggerVolume, the "Touch" event with the ball is detected using the bounding box of the ball, and not the ball itself. That lead to very strange behaviors sometimes, especially because this bounding box is moving and scaling all the time... strange, like if the ball was in fact a rolling cube, and not a sphere. Here is an image illustrating the problem, you can see the "Touch" log to the left when the blue box has just entered the TriggerVolume :

Touch ! That's wrong !

--> How can I say to volumes to "Touch" with the yellow bounds (the sphere bounds) or the simple sphere collision instead of the strange blue bouding box ?

A second problem, that may somehow be related to the first one, happens with collision components with my actors (actors that I create in UnrealScript for example).
On the following images, I have an Actor (let's call it A) on the center of the circle that have a cylinder component for collision component. The ball doesn't "Touch" this collision component like TriggerVolume before. On the next image, we can think we see a normal behavior, because the blue bounding box of the ball touches the cylinder component and the bounding box of the actor A, and there is no Touch detection (top view) :

No Touch ! This is normal.

The problem is that the "Touch" event happens when the ball enters in the bounding box of the actor A, instead of the collision component (cylinder) that I defined for this actor. Like here (top view) :

Touch ! That's unexpected !

I would like the ball to "Touch" the actor only when the ball touches the cylinder component, not its bouding box. In fact, I don't know if this red volume is actually the "bouding box" of the actor A, because it only shows up with the "show collision" command and... it's red. But I never asked for this red collision volume.
--> How can I solve this second problem (with properties, unrealscript, ...) ? Maybe the source of this problem is the same as the first one above.

In the ball Mesh properties, I have unchecked "Use Simple Box Collision" and "Use Simple Line Collision" (it is even worse if I check these). I also tried to change the collision type of the TriggerVolume and the actor A, but it leads to nothing. Where could I look now ?

Thanks for your time reading and helping me.
Have a nice day.

[Marenz]

For the first problem: Maybe it helps if you set the CollisionComponent of your ball to the same as the mesh is? Don't know whether that is already the case, just an idea.
Also, in the UDK Editor, if you edit the PhysicalAsset of the ball, you can make it use a simplified bounding box of type "Shpere" though I don't know whether this counts for the normal physics or for the actually touch logic.. or for both.

--Marenz

[Jereak]

Thanks for this quick response.
The CollisionComponent of the ball should already be the same as its Mesh, because it's a KActor, that inherits DynamicSMActor, that have "CollisionComponent=StaticMeshComponent0" in its defaultproperties. I tried to do it again in my ball subclass and it didn't change anything, so it may not be the source of the problem.

And isn't PhysicsAsset for skeletal mesh only ? Joints, shapes, ... ?

[Marenz]

I was typing from my memory, and the memory was wrong. What I meant was the "StaticMesh' in the static mesh editor of the ball-mesh. In the view menu you can enable "Collision" to see what it currently has.
If it is that box that you see, go to the collision menu and choose "sphere simplified collision". (again, just ideas)

--Marenz

[Jereak]

Ok ! Thanks again, but it's already "sphere simplified collision", it wouldn't roll so well if it wasn't.
By the way, in this StaticMesh editor, I tried to uncheck "consider for bounds" in BodySetup, it sounded well but it made no change at all.

[Jereak]

Up !
A little more information, perhaps it will help.
Here are the default properties of the actor A (the one with cylinder component for collision). I removed properties that have no relation with collisions :

defaultproperties
{
	// ...
	
	Begin Object Class=CylinderComponent Name=CollisionCylinder
		CollisionRadius=+00128.000000
		CollisionHeight=+0048.000000
		CylinderColor=(R=200,G=128,B=255,A=255)
		bAlwaysRenderIfSelected=true
		HiddenGame=true
		
		CollideActors=true
	End Object
	CollisionComponent=CollisionCylinder
	Components.Add(CollisionCylinder)
	
	bCollideActors=true
	bBlockActors=false
	
	// ...
}

Actor A is a subclass of Actor, it has no other properties about collision at all.

[VendorX]

For 1. and 2. use static mesh as collision...

[Jereak]

Hi !
That's the problem actually ! I don't know how to "use static mesh as collision".
If you mean trying that :

defaultproperties
{
        // ...

	Begin Object Class=StaticMeshComponent Name=StaticMeshComponent0
	        // ...
	End Object
	CollisionComponent=StaticMeshComponent0
	StaticMeshComponent=StaticMeshComponent0

        // ...
}

It's already done, because the ball is a subclass of DynamicSMActor (defaultproperties above are in DynamicSMActor ). Anyway, I tried to add it myself in the ball class and it was the same problem.
Did you meant something else ?

I think the problem comes from some properties in collision components or mesh, but I can't find where.

[VendorX]

Just add second SMC, use the same SM as first only make it a little bigger, set hidden, disable any lighting related stuff, any block except BlockNonZeroExtent, set CollideActors and bDisableAllRigidBody - Touch should be called...

...don't forget to uncheck Use Simple Box Collision and Use Simple Line Collision...

[willyg302]

This should help.

[Jereak]

Thanks for answers !

@VendorX : Perhaps I don't understand what you mean, but all theses properties are already set like that, and I already have Touch events. The problem is that there is no precision because of touching with the bouding box of the ball. Trying what you propose here doesn't change anything.

@willyg302 : That's exactly what I want to do ! Touching a Volume with a KActor precisely. So it wouldn't be possible with Touch, but with RigidBodyCollision ? I tried it, but I can't get RigidBodyCollision called, both in the volume class and in the ball class. Did I miss some properties somewhere ?
In fact, is it really possible to have a RigidBodyCollision with a volume ? According to your link, it should be, but I don't know how. What sneaky hidden properties must I change... ?
I have tried to change many properties, even changing the volume physics to Phys_RigidBody (it sounds stupid, I know).

[willyg302]

The code should be in the ball class (the KActor, in other words). To my knowledge no "sneaky code" is needed, if the volume is set up for collision then when the ball hits it, it will register as a rigid body collision. The actual component passed to RigidBodyCollision(), that is the "OtherComponent", will be the BrushComponent of the volume. So all you'd need to do is grab the parent of this brush component by doing something like TriggerVolume(OtherComponent.Owner) != none. This will test whether the owner of the component is a trigger volume. If it is, you do stuff.

Hope that makes sense!

[Jereak]

That makes sense, and actually that's exactly what I am trying.
Here is the code of my two test classes for this problem :

a sub-TriggerVolume :

class MyTriggerVolume extends TriggerVolume
	placeable;

event Touch( Actor Other, PrimitiveComponent OtherComp, vector HitLocation, vector HitNormal ) {
	`log("MyTriggerVolume Touch");
	if (OtherComp != NONE && MyKActor(OtherComp.Owner) != NONE)
		`log("Touches MyKActor");
}

event RigidBodyCollision(PrimitiveComponent HitComponent, PrimitiveComponent OtherComponent,
	const out CollisionImpactData RigidCollisionData, int ContactIndex)
{
	`log("MyTriggerVolume RBCollision");
	if (OtherComponent != NONE && MyKActor(OtherComponent.Owner) != NONE)
		`log(">>>>>>>>>>>>>>>>   MyKActor RB-DETECTED   <<<<<<<<<<<<<<<<");
}

defaultproperties
{
	Begin Object name=BrushComponent0
		CollideActors=true
		BlockZeroExtent=true
		BlockNonZeroExtent=true
		
		bNotifyRigidBodyCollision=true
		ScriptRigidBodyCollisionThreshold=0.0001
		
		RBChannel=RBCC_GameplayPhysics
		RBCollideWithChannels=(GameplayPhysics=true)
	End Object
	CollisionComponent=BrushComponent0
	
	bNoEncroachCheck=false
	bIgnoreEncroachers=false
	bCollideActors=true
}

and a sub-KActor :

class MyKActor extends KActor
	placeable;

event Touch( Actor Other, PrimitiveComponent OtherComp, vector HitLocation, vector HitNormal ) {
	`log("MyKActor Touch");
	if (OtherComp != NONE && MyTriggerVolume(OtherComp.Owner) != NONE)
		`log("Touches MyTriggerVolume");
}

event RigidBodyCollision(PrimitiveComponent HitComponent, PrimitiveComponent OtherComponent,
	const out CollisionImpactData RigidCollisionData, int ContactIndex)
{
	`log("MyKActor RBCollision");
	if (OtherComponent != NONE) {
		if (BrushComponent(OtherComponent) != NONE)
			`log("BrushComponent RBC-DETECTED");
		if (MyTriggerVolume(OtherComponent.Owner) != NONE)
			`log("################   VOLUME RBC-DETECTED   ################");
	}
	
}

defaultproperties
{
	Begin Object name=StaticMeshComponent0
		StaticMesh=StaticMesh'LLBPackage.Balls.Ball5.LLB_Ball5'
		
		CollideActors=true
		BlockZeroExtent=true
		BlockNonZeroExtent=true
		
		bNotifyRigidBodyCollision=true
		ScriptRigidBodyCollisionThreshold=0.0001
		
		RBChannel=RBCC_GameplayPhysics
		RBCollideWithChannels=(GameplayPhysics=true)
	End Object
	CollisionComponent=StaticMeshComponent0
	
	Physics=PHYS_RigidBody
	bWakeOnLevelStart=true
	
	bCollideAsEncroacher=false
	bNoEncroachCheck=false
	bIgnoreEncroachers=false
	bCollideWorld=true
	bCollideActors=true
}

I have created a map where a MyKActor (a ball in this case) rolls down and go in the trigger volume (a MyTriggerVolyme, of course).

- The ball rolls and collides very well with the world, bsp, staticmesh, other KActors, etc.
- The Touch event is called, I can see my four different logs in both classes ("MyTriggerVolume Touch", "Touches MyKActor", "MyKActor Touch" and "Touches MyTriggerVolume").
- I can see the "MyKActor RBCollision" log almost every frame when it rolls on the ground, but never when it hits the volume (no "MyKActor RBCollision" when the ball enters in and no "VOLUME RBC-DETECTED" log).

As you can see, I have tried many properties, true/false on theses and others... changing chanels, the value of ScriptRigidBodyCollisionThreshold...
Any idea ?

(Even better, if someone thinks he can make it work and can try to code this successfully, it would be great ! )

[Doublezer0]

in the properties for the TriggerVolume , have you tried adding BlockRigidBody=true ? I remember it being false by default which would cause a lack of event notices for rigid body collision.

[Jereak]

Hi there !
I added "bDisableAllRigidBody=false" in the BrushComponent of the Volume, it seems to be important, but it has no effect for now.

Doublezer0 : Actually, I don't want the ball to be blocked by the volume. I just want the TriggerVolume or the KActor to call the RigidBodyCollision event when the KActor goes through the volume.
Anyway, I tried what you said, and as expected it blocks the ball very well. I can see my "VOLUME RBC-DETECTED" log. The only problem is that it actually blocks the ball.
In fact, is it really possible to have a RigidBodyCollision without blocking ? For me, it should be, because a "collision" is not a "blocking", and Willyg302 seems to explain that it is possible (perhaps I misunderstood ?), but I can't figure out how.

Otherwise willyg302, if you successfully coded it like in the "More Accurate Trigger Events" article you wrote, perhaps you could show me this code in order for me to understand where I am wrong ?

It should be possible, because like I said in my first post, there is another kind of "collision volume" for one of my actors that has exactly the behavior that I want (Touches exactly when the ball itself enters in, ignoring the ball bounding box). The problem is that it didn't create this volume and I have no control on it... (that was the "second problem" in my first post, explained with the two last images).
So, detecting KActor with precision AND without blocking IS possible... but I don't know how to make it work with a "normal" volume.

[willyg302]

Weird that it doesn't work...what I have is a custom volume that extends DynamicTriggerVolume, and there's practically nothing in it (it's just different so my ball will not react to normal DynamicTriggerVolumes too). I'm not sure exactly what's missing, but after digging through the classes I found this in BrushComponent:

native final function SetNotifyRigidBodyCollision(bool bNewNotifyRigidBodyCollision);

This is the component that your volume owns. So you could do MyVolume.BrushComponent.SetNotifyRigidBodyCollisio n(true); and see if that works. But yes you're right "collision" and "blocking" are not the same thing, so it should be possible.

[Jereak]

Hum... actually, it's already done in the defaultproperties :

class MyTriggerVolume extends DynamicTriggerVolume
	placeable;

//...

defaultproperties
{
	Begin Object name=BrushComponent0
		//...
		bNotifyRigidBodyCollision=true
		ScriptRigidBodyCollisionThreshold=0.0001
		//...
	End Object
	// ...
}

And even with doing it again somewhere like in PostBeginPlay(), it doesn't change anything.