Method to Make a Movable Collision Mesh?

[Apollo13]

Assume I have an animated part. There is a collision mesh parented to that part. I then attach another part to it, such as a battery. When the first part animates, I want the second part to travel with it. Is this possible in Unity?

As of now, when I parent a collider to the animated part and add another part to the first part, as I animate the first part, the second is left behind clinging to the non-moving collider mesh.

thanks

[CaptainKipard]

I think collision meshes should be components of objects. Highlight the object that animates and add the component, choosing the mesh you want.

[Apollo13]

In Blender, I created the collision mesh. In Unity, I removed the mesh renderer and added the mesh collider to that collision mesh. That's what did not work.

[nli2work]

if you mean moving a part attached in VAB/SPH, it won't work. If you mean in Unity, it's a matter of attaching the component directly to the animated part; or childing the collider to the moving part in Unity.

You can move the collider if you child it to a moving transform in Unity, landing legs and gears do just that. animating the collider properties like radius, height, won't work, you will get an error about animation curves when attempting to load the model.

[Apollo13]

I don't mean in the VAB/SPH. I'm not trying to directly animate the collision mesh.

Here's what I tried:

1. In Blender, I created the collider mesh and and made the moving part its parent

2. In Unity, I selected the collider mesh and removed the render component. I then added the "mesh collider" component to it. Unity indicated that the collision mesh was a child of the moving part.

3. In KSP, I moved the animated part (parent) not the collision mesh. I tried this in both the VAB and the launchpad.

You make an excellent point about the lander legs and landing gear. I must be missing something.

Edited September 14, 2014 by Apollo13

[nli2work]

did you mark the mesh collider as "Convex"?

[Justin Kerbice]

In the other hand, landing gear and legs use special and dedicated module to handle them, which may, or may not, take care of the moving collider, which is not the case of the basic PartModule used by static parts.

I tired once with a kind of "corridor extender" without success, collider was generated by unity, convex and tied to the mesh.

It may be possible to do something with Infernal Robotics (like the piston for example).

[Apollo13]

Unity setup:

the result:

Edited September 14, 2014 by Apollo13

[Starwaster]

The problem is not that collision meshes are not movable, because they are.

The problem is that the position of the child part (the part you attached) does not get updated. It has a specific position relative to the parent part and once that position is set, it is not changed.

The game has no concept of an object being attached to a specific mesh on an object with multiple meshes. It's just attached to the object.

Edit:

Justin's probably right about IR. Or maybe not; I'm not sure if IR parts move just a part of a mesh or the entire object....... but maybe you can accomplish what you want using IR, or see how they do it.

Edited September 14, 2014 by Starwaster

[Apollo13]

@Starwaster: If I understand you, the battery in the above example cannot rotate with the red lever. The battery is attached to the object, which consists of the red lever and turquoise plane. True?

Edited September 14, 2014 by Apollo13

[Starwaster]

@Starwaster: If I understand you, the battery in the above example cannot rotate with the red lever. The battery is attached to the object, which consists of the red lever and turquoise plane. True?

Correct.

It doesn't even know which of multiple meshes it was attached to because the only real attachment is the object as a whole.

It's not practically possible.... (theoretically maybe but that's a big maybe)

"The technology involved in making something properly invisible is so mind-bogglingly complex that 999,999,999 times out of a billion it's simpler just to take the thing away and do without it......."

- Douglas Adams, Life, the Universe and Everything

[SpannerMonkey(smce)]

Hi tried to do just this very thing for ages, and i'm firmly of the opinion it can't be done , one of the IR chaps explained to me why, it's something to do with collider origins iirc, but this is the reason IR exists, because if it was possible we'd all have animated robot arms etc. It's a lot easier than you may think to incorporate an IR element in your hierarchy , check out the IR tutorial , that I can't find again. and if you do go down the IR route I'd be happy to help with any issues

[NecroBones]

If you look at the VESSEL blocks in your Persistence/Quicksave, all of the parts on your ship have their coordinates set relative to the root-node of the vessel. So no, the battery will never move.

[nli2work]

you need Infernal Robotics for that.

[Apollo13]

Thank you all for the replies. That saved me a lot of hours trying to figure out something that can't be done, except through IR.