Fixed joint

[Araqiel]

Is there a way to create a joint where the two attached bodies can't move at all relative to each other?

I suppose I could hack it by trying to supply 0,0 for the axis of a prismatic joint, or combining a prismatic joint with a distance joint... but neither of these are very elegant.

The most rigidity I can get, the better. I may just end up making a work-around...

[Ryne]

I'm sure Taehl might be able to help you, or you could try looking at his code I guess. He's been working on a game based around plant growth. It works with joints, similar to what you're looking for.

http://love2d.org/forums/viewtopic.php?f=5&t=2244

[Robin]

@Ryne: I don't think those plants use physics…

Is there a way to create a joint where the two attached bodies can't move at all relative to each other?

I suppose I could hack it by trying to supply 0,0 for the axis of a prismatic joint, or combining a prismatic joint with a distance joint... but neither of these are very elegant.

Or a PrismaticJoint and a RevoluteJoint? They are each other's complement, so I think it is less hackish than the other ways, albeit far from elegant.

[Taehl]

Nope, my plants are physics-less. At about 200 pieces per plant, Box2D probably wouldn't be able to keep up, anyway.

As far as a physics-based solution for that... Hm. Well, I haven't used the physics engine much, but couldn't you just attach both of the objects to a rectangle which is invisible and doesn't collide with anything?

[Robin]

As far as a physics-based solution for that... Hm. Well, I haven't used the physics engine much, but couldn't you just attach both of the objects to a rectangle which is invisible and doesn't collide with anything?

Then the problem remains, doesn't it?
Instead of object a <-> object b, you suggest doing object a <-> rectangle <-> object b, where "<->" is a way of jointing together two things without allowing any —

Wait. Wait a minute.

Araqiel: two attached bodies you say? Do they have to split apart at one point? If not, why not use a single body? You can attach more than one shape to a body, IIRC.

[Araqiel]

Yeah, I finally decided that it'd work to use one body and multiple collision shapes. When they need to split, just break that piece off into its own body.