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Bullet Physics - Saving Solution ?

mmoriarty311_698a63361bmmoriarty311_698a63361b Posts: 0
edited December 1969 in Carrara Discussion

Is it possible to save the solution from bullet physics? I have created a tower of about 2000 scaled cubes. I run the simulation . . . looks good. play around with camera position. etc and do a quick render. Save everything. Comeback later and open the file. Run animation (without re-running the Simulate button). The animation mostly runs but 1or two frames per second jump the wrong frame. It will run for the first 10 frames and then frame 11 will be the same as frame 2 then frame 12 will be correct again and continue for several frames and then another out of place frame. Is this a known issue.

Am I missing something when I save?

If I just re-run the Simulation button, I get a different solution so then my original camera positions don't work any more.

Comments

  • evilproducerevilproducer Posts: 9,050
    edited December 1969

    If the simulation is the way you want and you don't need to run it again, would it work to convert it to keyframes when it's done?

  • mmoriarty311_698a63361bmmoriarty311_698a63361b Posts: 0
    edited December 1969

    I only tried that once but Carrara crashed. I assumed 2500 objects is just too much to keyframe.

  • evilproducerevilproducer Posts: 9,050
    edited December 1969

    Yeah, might be! :lol:

  • DUDUDUDU Posts: 1,945
    edited December 1969

    It could be you don't have RAM enought... ?

  • SockrateaseSockratease Posts: 813
    edited December 1969

    Is it just the preview skipping frames, or the render output as well?

    There is a button above the timeline to make sure it does not skip frames on previewing - without clicking that, it often skips frames in playback of previews.

  • mmoriarty311_698a63361bmmoriarty311_698a63361b Posts: 0
    edited December 1969

    I don't think it's a RAM shortage, I have 8GB

    MacBook Pro, 8GB Ram, 2.2GHz Intel Core i7, OSX 10.7.5

    I made sure I had the "Play Every Frame" on when I ran the simulation, and when when I saved it. When I re-opened it I made sure Play Every Frame was on as well but same result. Also, it's not like it is just skipping frames. It is like some frames have all the objects reverted to positions from several frames back or even from the first frame of the animation then the very next frame will look like it should.

    So based on the responses so far, this is not a common problem. I was hoping someone would recognize this problem.

    It

  • mmoriarty311_698a63361bmmoriarty311_698a63361b Posts: 0
    edited December 1969

    . . . and have a ready solution. I'll keep looking but I'm not coming up with anything in my searches so far.

    Thanks for the responses though.

  • tbwoqtbwoq Posts: 238
    edited December 1969

    Hi photonprez.

    Carrara doesn't have a separate bake or cache for physics, only what is saved with the scene. Your issue could be a bug(?). I haven't tried anything with 1000's of physics objects yet(using C8.1 Pro), but I did have crash issues in C6 with to many keyframes from converting physics. If your physics can be converted back to keyframes, you can create animation group then make an NLA master clip. This saves the simulation(or keys) in a clip form way.

    Tip; if you are using simple cubes, try using cubes made from the Spline modeler. Spline objects appear to simulate much faster.

  • Dave_5690Dave_5690 Posts: 19
    edited December 1969

    photonprez,

    I have the same problem. Did you ever find a resolution?

  • mmoriarty311_698a63361bmmoriarty311_698a63361b Posts: 0
    edited December 1969

    No solution yet. Would like to find one though. I have a couple of projects that I have abandoned until I can find a solution.

  • DUDUDUDU Posts: 1,945
    edited December 1969

    I will try to explain with what makes me think this problem:
    I make my renders in sequences of images and if their classification is not correctly made (000-001-002… for a sequence of less than 100 images)), when I import the file of images in the Premiere or AE project, the images are not placed in the good order on the timeline.
    1,3…19, 2,20,21…29,3,30,31… etc
    I think that it is same logic for the safeguard of the ".car" project.
    I also think that the originators of Carrara did'nt think that the computers would become so powerful to be able to manage so many objects (physical) in the same scene, perhaps that it is only a simple update of the program which could solve this problem ?

  • Dave_5690Dave_5690 Posts: 19
    edited December 1969

    My solution was much smaller than photonprez's, so I can confirm that converting to keyframes first allows it to save just fine. Shouldn't have to though. I logged a ticket.


    Anyone know what's up with the crazy jumping pieces occasionally in the physics solution? Pieces seem to randomly just take off, even after they've settled down.

  • Sci Fi FunkSci Fi Funk Posts: 1,198
    edited December 1969

    Is it the number of the objects or the complexity of them that is causing the crash?

    I wonder what happens if you try the same scene with low poly proxy's?

    It will calculate faster for sure!

  • tbwoqtbwoq Posts: 238
    edited December 1969

    dave said:
    ... Anyone know what's up with the crazy jumping pieces occasionally in the physics solution? Pieces seem to randomly just take off, even after they've settled down.

    The physics popcorn effect where objects suddenly jump around or fly out of scene, could be a failed collision detection value/keyframe or the physics trying to readjust the collision distances etc.

    In my experience, most of the time this happens with the Standard method rigid body and Bullet soft body physics. Manually moving the objects slightly in scene or adjusting the Physics tab physics engine properties can help, but theres still no guarantee/workaround that the simulation won't have errors.

  • DUDUDUDU Posts: 1,945
    edited December 1969

    I solved the problem by putting the slide on zero for the distance of collision in the parameters of the scene.

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