Physics and contraints in Carrara - Polyloop

derk · 25th February 2006, 13:56

Hi to all.
I am trying to create a simple animation that uses a combination of physics and contraints. I cannot get it to work.
I am trying to build a catapult.
A ball is placed on a piece of wood. If I apply physics to the wood and the ball, I cannot get the wood to rotate around an axis even though I set up the contraints.
If I then disable physics for the wood and set explicit movements to it, the constraints work, but the ball just moves through the wood.
How can I do this? Any suggestions?
I included the carrara file

isdnmodem · 25th February 2006, 15:00

derk,

May be this can start you thinking in another direction

Try changing the angle of force to value of - the angle value of your cube.
and adjust the force according to the angle.

Here is the file, its not perfect but something to start with.

derk · 25th February 2006, 18:19

Thanks a lot for this.
It looks a lot better. What I do not understand is: Why did the ball went through the cube in my file?

isdnmodem · 25th February 2006, 18:50

Because the force was pointing downwards

derk · 25th February 2006, 19:37

Yes but with collission detection turned on, I can understand that the ball moves downward, but not through the cube. Why is that?

isdnmodem · 26th February 2006, 02:18

I think when Physics is enable on an object it ignores the collision detection and works on the Collide mode in the property. Eovia might have a better answer.

derk · 26th February 2006, 11:50

Thomas? Could you help out with this question?

Thomas · 26th February 2006, 20:32

Collision detection is only when you move -manually- objects, to lay on them where you want. But it's not a kind of "Physic property. Don't even think about it for your animation.
I have to take a look at your file.. but I'm currently pretty busy (that's why I'm a little bit off the forum this last couple of days..

derk · 26th February 2006, 22:39

Thanks a lot Thomas for your reaction.
Ok I understand what you say about collision detection. I do think however that when 'collide with other objects' is selected for the items in the scene, that the objects should not fall through each other. This does not always seem to work correctly.
Anyway, once you have some time, I appreciate if you can take a look at it.
Thanks in advance

26th February 2006, 20:32	#8 (permalink)
Thomas Always learning new stuff Join Date: Jul 2002 Location: Merignac, France Posts: 11,316	Collision detection is only when you move -manually- objects, to lay on them where you want. But it's not a kind of "Physic property. Don't even think about it for your animation. I have to take a look at your file.. but I'm currently pretty busy (that's why I'm a little bit off the forum this last couple of days.. __________________ Polyloop owner & Administrator - no support by PM or email. Polyloop [EN/FR] - Meuuh [FR +16 ans] - Totyo [FR] - Pixologic [JOB] - Le ZBlog [JOB] - La3dpourlesnuls [FR]

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25th February 2006, 18:19	#3 (permalink)
derk Vertex Join Date: Oct 2005 Posts: 24	Thanks a lot for this. It looks a lot better. What I do not understand is: Why did the ball went through the cube in my file?

25th February 2006, 18:50	#4 (permalink)
isdnmodem Extrusion Join Date: Jul 2005 Posts: 184	Because the force was pointing downwards

25th February 2006, 19:37	#5 (permalink)
derk Vertex Join Date: Oct 2005 Posts: 24	Yes but with collission detection turned on, I can understand that the ball moves downward, but not through the cube. Why is that?

26th February 2006, 02:18	#6 (permalink)
isdnmodem Extrusion Join Date: Jul 2005 Posts: 184	I think when Physics is enable on an object it ignores the collision detection and works on the Collide mode in the property. Eovia might have a better answer.

26th February 2006, 11:50	#7 (permalink)
derk Vertex Join Date: Oct 2005 Posts: 24	Thomas? Could you help out with this question?

26th February 2006, 22:39	#9 (permalink)
derk Vertex Join Date: Oct 2005 Posts: 24	Thanks a lot Thomas for your reaction. Ok I understand what you say about collision detection. I do think however that when 'collide with other objects' is selected for the items in the scene, that the objects should not fall through each other. This does not always seem to work correctly. Anyway, once you have some time, I appreciate if you can take a look at it. Thanks in advance