Rigid Planes Move Away

Discussions about rigidbody simulation in Realflow 4
shaun_michael
Posts: 4766
Joined: Sun Sep 10, 2006 8:04 am

Rigid Planes Move Away

Postby shaun_michael » Fri Aug 17, 2007 3:47 pm

Hi Stephen,

I've taken a look at it and run the sim and all appears normal - initially. Just to check I ran the simulation again, and this time there were some pieces not showing in the viewport and the movement was slightly erratic although I dont think anything nearly as erratic as your movie shows. Very weird.

Anyway, I closed RF and shut down the PC to go off and do something else for a while whilst mulling over your problem and came back and after restaring the system, running RF for the first time, ran the sim and it came through - as far as I can see - absolutely fine. I'm seeing 26 objects and the dynamic motion is fine for how you have it set-up.

So, I've saved the scene under a different .flw file (sequence3) and rezipped the scene including the data generated from my sim.

Download Link (approx 2.08MB zip)

I thought I'd let you look at my sim to see if it worked on your system fully intact before continuing to look for a reason so that you could get on with your work if it was what you were after. Meanwhile, I'll test out what I found earlier to see if it repeats itself.

Shaun


shaun_michael
Posts: 4766
Joined: Sun Sep 10, 2006 8:04 am

Rigid Planes Move Away

Postby shaun_michael » Fri Aug 17, 2007 3:58 pm

Nope, completely mistaken. Must have been a long day. What I'm seeing is your object's pivot points offset somewhat meaning I assume you modelled your object away from the origin in your 3D application and then cloned it.

Ran the sim again, and again, no problems.

Shaun

Refillable
Posts: 13
Joined: Thu Dec 07, 2006 1:15 pm

Rigid Planes Move Away

Postby Refillable » Sat Aug 18, 2007 1:57 am

Hey Saun,

thanks for your help so far, I appreciate it.
I tried to open your data in RF, but it crashes everytime. I have to add, that the simulation in RF looked here good to, but when you import it in the 3D app (maya)
it is getting this strange moving planes like in the movie.
I thought maybe it is an old object file, so I deleted everything an ran the sim again and imported again in maya, but still the same problem.

shaun_michael
Posts: 4766
Joined: Sun Sep 10, 2006 8:04 am

Rigid Planes Move Away

Postby shaun_michael » Sat Aug 18, 2007 9:20 am

Which version of RF are you using Stephen? I ran the sim on RF4.3. This could be the reason for the scene not loading.

Was I correct in my assumption about how you made the original objects? Are they clones of an object that wasn't created around the origin? Judging by the offset pivot in RF that was my assumption and i thought that perhaps you should remake one object ensuring it's centred around the origin and then clone it from there.

Shaun

Refillable
Posts: 13
Joined: Thu Dec 07, 2006 1:15 pm

Rigid Planes Move Away

Postby Refillable » Sun Aug 19, 2007 11:07 am

shaun_michael wrote: Which version of RF are you using Stephen? I ran the sim on RF4.3. This could be the reason for the scene not loading.

Was I correct in my assumption about how you made the original objects? Are they clones of an object that wasn't created around the origin? Judging by the offset pivot in RF that was my assumption and i thought that perhaps you should remake one object ensuring it's centred around the origin and then clone it from there.

Shaun

you´re right, the Version I use is 4.2 so I think this is the reason.

As for the objects, I created a box, scaled it down, without moving it and then duplicated it. I didn´t realize, that the pivot has an offset, maybe the is the problem.
I will try an do it without duplication and create new ones every time, because the first was in the origin....I let you know, if it works.

Refillable
Posts: 13
Joined: Thu Dec 07, 2006 1:15 pm

Rigid Planes Move Away

Postby Refillable » Mon Aug 20, 2007 10:26 am

sooo, I finally got it working. It was because of the offset of the pivot. I imported just one object and duplicated it in RF and this works fine, so thank you very much shaun for the help here.
But now another Problem came up, I try to make an gravity upwards, which should slow down the boxes, but it has no influence on anything...also when I put in a drag force, it has no influence.
the daemon is in the global link box, I gave it a box boundary.
any thoughs on that one?

shaun_michael
Posts: 4766
Joined: Sun Sep 10, 2006 8:04 am

Rigid Planes Move Away

Postby shaun_michael » Mon Aug 20, 2007 1:36 pm

Whats the end effect you're trying to produce by adding an inverse gravity force. BTW, have you tried adding a negative gravity force rather than rotating the normal one?

Also, you can use a rigid body's air friction to slow it's decent if you choose.

Hope that helps.

Shaun

Refillable
Posts: 13
Joined: Thu Dec 07, 2006 1:15 pm

Rigid Planes Move Away

Postby Refillable » Tue Aug 21, 2007 9:01 am

The effect I wanted to achieve was to slow down the animation. to change the air friction has worked fine with that, thanks.
There is yet another problem, when I import the animation into maya, the objects overlap each other and sometimes sink into each other.
In RF everything is looking good.
I changed the primitive into mesh and played with fixed substeps, but it didn´t help.
Sorry for all this propably easy questions, but I didn´t work much with this prog.


thanks.

shaun_michael
Posts: 4766
Joined: Sun Sep 10, 2006 8:04 am

Rigid Planes Move Away

Postby shaun_michael » Tue Aug 21, 2007 9:09 am

Hmmm, interesting. You say that there is definitely no overlapping occuring in RF? I dont quite understand in that case why Maya would be changing the positions of each object to cause the overlapping. If you can, have another look at the RF side of things for the overlapping. If you're finding it is in there try turning on the "stacking" option in the simulation options (next to the simulate button.

Start off with a low value and work your way upwards. I've also found that increasing the poly count of your collision object can help, but don't over-do it. If your collision object has 12 polys, try doubling it.

On the Maya front I'm afraid I'm unable to shed any light, but as you're just tranfering keyframes from RF to Maya my first port of call would be RF.

Shaun


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