Hi all,

I have created a 2d grid in msd and I have a question regarding the use of force...

I'm going to have to mix my metaphors here I think:

Is it possible to send force so it acts almost like in layers so that, say, I have my grid;
 ._._._.
|._._._.|
|._._._.|
|._._._.|

which is fixed.

I would then like to add a ball (for want of a better descriptor) which can travel around the grid by being 'blown' by an overall x,y type force (which I already know msd has/can do).  On top of this I would like the separate masses and links to be capable of speeding up and slowing the 'ball' as it travels around the space.

Pinball on train-tracks sort of thing (how's that for a simile:)

Is this even possible and if so how do I go about it?

Also, what's the best way of doing the grid?  At the moment I have one version where all the masses are fixed and another where just the corners are fixed.

Many thanks in advance,

Julian