gravity for certain material instance

Hi Behzad,
you can mimic (anti)gravity by prescribin permanent force on certain bodies.

########################################
bs = (
   sphere(( 0,0,0),1),
   sphere(( 5,0,0),2),
   sphere((11,0,0),3),
   sphere((20,0,0),4),
)
O.bodies.append(bs)

for i,b in enumerate(bs):
   m = b.state.mass
   g = ((-1)**i) * Vector3(0,1e-6,0)
   f = m*g
   O.forces.addF(i,f,permanent=True)
########################################

Cheers
Jan

Thanks Jan. It's a good idea. However, my concern is that this is supposed to cover future bodies as well. What you suggest can take care of only already existing bodies.
Can we do similar thing but specify the material type (like let's say vaporMat which can be a FrictMat instance) so whenever a body with this material is created during iteration, it applies the anti-gravity force?

cheers

sure:
######################
vaporMat = FrictMat(...)
...
b = ...
O.bodies.append(b)
if b.mat == vaporMat:
   O.forces.addF(b.id,f,permanent=True)
######################
Jan

Well, this won't cover future bodies. I need to repeat this command whenever a new vaporMat is generated. Or embed it in a pyRunner which I didn't want to.

Thanks anyway. :)

> I need to repeat this command

Is it a problem? from source code point of view, you can of course wrap all it into one function
#
def myOBodiesAppend(b):
   O.bodies.append(b)
   if b.mat == vaporMat:
      O.forces.addF(b.id,f,permanent=True)
#
Then you just call this one function
cheers
Jan

Good, that's what I meant!