Ok a few years ago I posted that I was having problems with Plastic Spheres sinking into ground plane instead of bouncing around.  I thought this might be a bug in Carrara 5 pro.  Now I'm using Carrara 6 Pro and I still have the same problem.

Physicial Properties
Collide with other objects Checked.
Material: Plastic
Density: 1.100
Bounce: 70%
Friction: 10%

Spheres sink midway, I'm attaching image for reference.  I've tried tilting the ground plane to make some fall off which they do but some still stick and sink.

 Particles are "pretend" objects and don't actually exist. So, Carrara calculates the collisions based upon the hot points of replicated objects. The trick is to make an invisible object above the floor for the hot point to collide with.

Thanks.. I'll make another ground plane make it invisible and set it slightly higher than the visible one and see how it works.

ok... so the dilema now is that , I cant place any objects ontop of the ground plane without them looking like they are floating.. and if I make the gap between the visible and invisible plane, to little, the bottoms of the spheres start to look sinked in again.

I can turn off collision detection on the objects to be placed on the ground, but than the spheres dont bounce off them, and effect that I'm trying to achieve is lost.

I tried changing hotpoints on the particle generator and the ground plane and no luck.

 Since I'm not sure what kind of motion you are requiring, if you are running into issues with the particle emitter, you can instead use the replicator and convert into real objects. Just make sure to set the physical properties of the replicated object prior to converting.

These converted objects will respect other physical forces in the scene also.

Mark you are a genius!! :)

Ok I will try this and see how it works.  I just want to drop spheres, that as dropped interact with objects around by bouncing on and off of them.  Kind of like a rubber ball.

 This will do the trick then. :)

Mark
I am missing some understanding about the replication idea/particles actions
Any chance of spelling it all out for my slow old brain please.

Brian.

bwtr

 Hi Brian,

The physical interaction of particles is different than other shapes in your scene when working with collisions. Carrara will correctly "bump" objects into one another for everything EXCEPT particles.

Particles are instantiated - that is, ghosts of the source object and are kept track of only by the hot point and nothing else. So, when particles collide with objects, all Carrara is tracking is the hot point, not the geometry. This results in the visible particles penetrating other objects in the scene up until the hot point collides with another object.

Mark

Hi Mark
Sorry if I am having a thick day--again.
OK. the particles can be changed into objects--say spheres.
But, where does the Replicator idea integrate into that please?
(Unless you are only saying the number of emitters can be increased by the Replicators?)
Brian

bwtr

 No worries. The Replicator, unlike the particle emitter, allows you to convert the replicated objects into actual geometry. Then the real geometry acts like any other geometry and responds to collisions correctly.

Marks explanation make perfect sense.

If my scene only had the Ground Plane and Particles falling onto it, I could simply do the trick he suggested in earlier posts, where I create another plane but make it invisible.  The Particles will fall through the invisible plane partially and will look as if they are ontop of the solid plane.

Since I have other objects in the scene the particles will not interact with I need to utilize the method of converted objects.

I just got back from a concert and its late at night I will try this method and report later :)

Is this what is meant? I have the replicator set at 1. Brian

bwtr

• If the Replicator is the Parent and the Particle Emitter is the child than I get a mess because the particle generator itself is replicated.

• If the Particle Emitter is the Parent and the Replicator is the child nothing changes spheres still sink.

I must be missing something.

I was looking at Brians example and I see a sphere, where did that sphere come from?

In the advanced (second tag) down in the lower LH corner of the Particles workings is where you access a "real" object rather than a particle. I used the standard Sphere at 1.00 size I think?

BUT--- I still can not work out why I need the Replicator and neither, in the replicator mode, how to stop the sinking into the ground?

And I had the Replicator as only 1 therefore no "mess"!

Brian

bwtr

Thanks for the info Brian, and yes I've got the same results as you did.

I've been playing with different variations and settings.

This is what I tried.

Particle Emitter -> Basic -> Shape -> Objects

Advanced -> Replicated Objects -> Replicator

I also added a sphere to the Replicator.

Oh and also created a converted replicator, which changed
the behaviour of the particles bouncing everywhere but still sinking problem.

Same thing the replicated Spheres are sinking.

Another description of what I'm trying to achieve is to create the effect of droping a bucket of tennis balls onto a floor.  The balls simply bounce around everywhere and eventually rest/stop moving.