should be simple rigid body question

# 1 22-10-2008 , 02:29 AM

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Location: Denver, US

Posts: 48

Hello.
Trying to setup something simple, but no joy.
Just as a test:

Two poly cubes, one above the other.
The one above is thinner than the one below.
Nurbs floor plane.
Select both cubes and set gravity field and set nurbs floor as passive body,
Cubes drop and lay on each other and the floor, as expected.

If I set up the same as above but before I inroduce gravity, I select the top cube and delete the bottom face and then continue as before.

When the cubes drop, now the top one drops through the bottom cube and rests on the floor.

Why won't the top cube merely rest on the bottom cube, on it's topmost face, instead of just falling through the bottom cube geometry.

Maybe not possible?

Thanks for your time.

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# 2 22-10-2008 , 02:51 AM

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Not too sure if this is correct, but it might be that the face normals for the top cube are facing the other way.

I would model the cube without the face using extrusions so its "solid" or watertight so to speak, it should work no probs then

"No pressure, no diamonds" Thomas Carlyle

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# 3 22-10-2008 , 02:58 AM

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You nailed it.
I just reversed the normal for that top face and it works fine now.

Thanks a ton, mate!

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# 4 22-10-2008 , 03:00 AM

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No Probs

"No pressure, no diamonds" Thomas Carlyle

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# 5 22-10-2008 , 08:27 AM

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Hey Erik, nice to see you again.
Don't be a stranger.

Please feel free to post questions more than once every couple of years user added image

We're all here for ya!

Welcome back user added image

ragecg
Dynamics/Effects Moderator

Israel "Izzy" Long
Motion and Title Design for Broadcast-Film-DS
izzylong.com

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# 6 22-10-2008 , 08:44 AM

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Hi Rage,
nice to see you too.

While I have you, user added image

,

would you know the process of connecting or parenting a soft body to a rigid body and have them both react together to a collision object?

I am building a simulation of a gift box falling open, so the box lid shape would be rigid, obviously, but there is a ribbon/bow on the top, so my hope was to make that top piece a soft body and then join the two somehow and have them fall together and react/bounce to a floor. I know one way would be make the ribbon and lid one piece of geometry and then adjust the weights at the ribbon to make them more soft, but applying materials would be easier if they were separate shapes.

One thing that is perplexing and probably wrong... maybe a collsion object can't also be a passive object for the rigid body? Maybe I make a copy and one is a collision object and one is a passive body?

I'm hoping this is more straightforward than what I am thinking...

Thanks for your time!

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# 7 22-10-2008 , 03:07 PM

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Originally posted by erikober
Hi Rage,
nice to see you too.

I'm hoping this is more straightforward than what I am thinking...

Thanks for your time!

Originally Posted by

Actually, it is user added image

The answer will be one of those "oh my gosh, I forgot about that!!" sort of answers, hehe..

However, since the answer would help everyone, and it is not related to your original post in this thread, would you mind posting another completely new thread in this Dynamics & Effects forum so I may quickly answer you/everyone with the answer?

Awesome, thanks!

PS, lemme give you a hint.... nCloth user added image

Israel "Izzy" Long
Motion and Title Design for Broadcast-Film-DS
izzylong.com

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