Please help with a basic physics scene!

cobusp

Hi all.

I have this basic scene with 5x duplicated, low geometry bill packs that I just want to fall down on the floor. But, for the love of Mike -- no matter what I try, it doesn't work. The bottom-most object falls alright, but the other ones just stay in the air! This is with bullet physics. If I switch to standard physics, they fall down, but they then go through the floor!

WIll someone be so kind to have a look at my file and advise?

 

Diomede

Here is a physics tutorial I haven't seen before.  I am wondering if it has to do with your duplicates.  Did you get a choice to edit the master or create a new master when you set the physics for the first cash pack?  

WendyLuvsCatz

I find it impossible to get duplicates to be treated as separate objects as far as properties go

the exception being lights and cameras

meshes keep all the same attributes especially in the vertex room but you can get a create new master dialogue applying some other changes

however replicated objects converted to real instances work

 

video

Diomede

Good to know.  Thanks, Wendy.

cobusp

Thanks for that tutorial. It covers elementary physics. I have ceased working with duplicates -- I now copy and paste objects. I used to use the replicator and turn the objects into real instances, but even though there were not too many instances, physics would just cease to work properly. So now, I've only used a few copied and pasted versions of the same object, and this still doesn't work out. When switching to Standard physics, at least the objects fall down, but then they fall right through the floor! These tests were done with various, simple vertex objects. Parametric objects (such as 3D text or spline-generated objects) work much more consistently with physics.

Conclusion: Physics in Carrara is useless -- the only times it works reliably is when using parametric objects.

 

Diomede

I have not used Carrara's physics very much.  But I did use it for a bowling animation in a recent challenge.  The bowling ball and the bowling pins worked about as expected.  The bowling ball was a vertex object.  The bowling pins were objects that came in the old Carrara content files, so presumably spline.

WendyLuvsCatz

I an not sure what is going on with your scene but I myself use physics quite a lot

duplicated objects do work for me too but they share the same properties which is not always ideal

are you looking at scene settings and collisiondistance, geometric fidelity, simulation accuracy  etc?

is your plane subdivided eniugh?

I set the accuracy to 1K, fidelity to 100, collision to 1

 

cobusp

Thanks for your comments. One thing I did wrong was to set the collusion to 100 (I thought 100 was best; a bit misleading). 

However, this didn't solve my problem. But I did come to a new insight where physics and geometry are concerned: the problems come in when one imports geometry from another app. (I'm doing most of my modelling in Cinema (much, much better). These are the problems that crept in when I exported the geometry to:

 

1. Obj - the normals got flipped (no wonder the object behaved so erratically. I fixed this, but for some reason, one polygon would continuously render as invisible! No matter what I did. Ok, so next I tried Collada:

2. Dae - imports beautifully, but the UVs were corrupt. I couldn't fix this in Carrara's UV mapper. Ok, so next I tried:

3. FBX - for some reason those format imports as "Corrupted" in Carrara. Ok, so the next thing tried was the final solution:

4. 3DS - imported perfectly, and the UVs worked great

One thing I find lacking though, is the ability to apply physics characteristics to entire groups. I have to go and set the physical characteristics for each group item individually.

Hopefully this solution may help someone else in future.

 

cobusp

Here s the final result of my physics trials and tribulations - it eventually came out pretty well.