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Speeding up slow dForce simulations

jukingeojukingeo Posts: 711
in New Users

Hello All,

I have a question in regards to dForce simulations.  On my machine a 60 frame simulation takes a half hour to 45 minutes to complete.  I know 30 frames is the standard but I usually take a simulation out to 45 or the full 60 frames to allow time for clothing to settle.  I know things are not going to be very fast because I am only using a CPU right now as I don't have a graphics card, but I have seen videos on You Tube with machines that have a less powerful processor than mine manage to do a 60 frame simulation in 2 - 10 minutes.  I know speed might be related to content as well, but right now I am only simulating a skirt, not even a full dress.  So I have no idea why a simulation is taking so long.  So my question is what can I do to speed things up a bit?

Thanks!

Comments

  • L'AdairL'Adair Posts: 9,479
    edited March 2019

    dForce sees every single visible item you have in the scene.

    The only items you want visible will be the item(s) you are simulating and the item(s) they are colliding with.

    There are two ways to make unnecessary objects not visible: either hide them in the scene, (you don't see them in the viewport or render,), or uncheck "Visible in Simulation" for those items. You can select all the items to hide in the Scene tab, then select all of them in the parameters tab. Type "visible" in the filter field above the right column to isolate the visibility options. Both Visible and Visible in Simulation should be among the isolated options.

    My preference is to click on the Visible button to turn it off. My logic is if I can't see it, I know it's not visible in the simulation. Just as I know if I can see it, it is visible in the simulation.

    For example, if you are simulating a dress on a G8 female figure, hide her hair and eyelashes. You'll probably want to hide shoes/boots and jewelry, unless the dress will need to collide against them. And if there is anything else in the scene—house, car, table and chairs, trees, other characters, and so on—you need to hide those.

    If she will be sitting by frame 30, you'll need that chair, of course. If the dress is long enough to fall on the floor, you'll need either the floor of the set, or my personal favorite, a single polygon plane primitive to mimic the floor.

    The fewer items visible to dForce, the less calculations it will need to make, and the faster the simulation.

    (And for the record, I typically simulate using the Timeline at 60 frames, final pose at frame 30.)

    Post edited by L'Adair on
  • DDCreateDDCreate Posts: 1,398

    Great info! I didn't know this! I dForce a lot when I'm making certain kinds of pictures and groan about the amount of time I know it's going to add to the process. I didn't realize dForce saw everything. I just figured it was only focused on that had dForce applied to it. Thanks for those nuggets of wisdom L'Adair!

  • jukingeojukingeo Posts: 711
    edited March 2019
    L'Adair said:

    dForce sees every single visible item you have in the scene.

    The only items you want visible will be the item(s) you are simulating and the item(s) they are colliding with.

    There are two ways to make unnecessary objects not visible: either hide them in the scene, (you don't see them in the viewport or render,), or uncheck "Visible in Simulation" for those items. You can select all the items to hide in the Scene tab, then select all of them in the parameters tab. Type "visible" in the filter field above the right column to isolate the visibility options. Both Visible and Visible in Simulation should be among the isolated options.

    My preference is to click on the Visible button to turn it off. My logic is if I can't see it, I know it's not visible in the simulation. Just as I know if I can see it, it is visible in the simulation.

    For example, if you are simulating a dress on a G8 female figure, hide her hair and eyelashes. You'll probably want to hide shoes/boots and jewelry, unless the dress will need to collide against them. And if there is anything else in the scene—house, car, table and chairs, trees, other characters, and so on—you need to hide those.

    I knew about hiding items of clothing that you don't want to interact with the simulation and also selecting the item to apply the dForce simulation on, but I didn't know that applied to all of the items in the scene as well.  I tried it again tonight just using the main building and turning everything else invisble.  That managed to get the simulation down to 5 minutes.  I would like to get this down even more, but I know that will not happen with the current render due to the large structure.

    L'Adair said:

    If she will be sitting by frame 30, you'll need that chair, of course. If the dress is long enough to fall on the floor, you'll need either the floor of the set, or my personal favorite, a single polygon plane primitive to mimic the floor.

    That is a good idea too, using a primative for the floor. Come to think of it, I could have made a box primative to mimic the wall and hid the building too and that probably would have sped things up.

    L'Adair said:

    The fewer items visible to dForce, the less calculations it will need to make, and the faster the simulation.

    Sounds good!

    L'Adair said:

    (And for the record, I typically simulate using the Timeline at 60 frames, final pose at frame 30.)

    This tidbit I picked up from someone on YouTube and use it as well.  The only time I don't use the Timeline is if I just have the character standing without too far leg movements. Then I go with the single frame simulation.

    DDCreate said:

    Great info! I didn't know this! I dForce a lot when I'm making certain kinds of pictures and groan about the amount of time I know it's going to add to the process. I didn't realize dForce saw everything. I just figured it was only focused on that had dForce applied to it. Thanks for those nuggets of wisdom L'Adair!

    I have to laugh as I am the same way.  I groan everytime I have to use dForce.  While it is nice when it works, it is very finicky and you do one tiny thing wrong...the dress (skirt, scarf, etc) explodes!  Then there is the simulation time too.  So it just adds considerably to the overall creation process.   I do like to use dForce to make standing poses look more natural.  It usually works fine with laying down poses too.  But when it comes to sitting poses, many times I would rather just grab a dress that has sitting morph controls and be done with it.

    I did this render tonight with one of my characters sitting on a wall.  It took me over 2 hours to get to that point...not including the render time:

    I had trouble in the positioning as I had her too low in the simulation.  Then she was sitting too far down on the wall and that was causing explosions and that took me a while to realize what was happening.  So it took a long time before finally getting the dress right.  So dForce certainly does add it's fair share of headaches, BUT when it works, it looks pretty good.

    Thanks for the info!

     

     

     

    Anna-SpanishMidnightdressRomaPlazaSittingOnWall.png
    989 x 1280 - 2M
    Post edited by jukingeo on
  • Richard HaseltineRichard Haseltine Posts: 100,781

    You don't have to fully hide the items, just turn Visible in Simulation off. That way you don't have to unhide before rendering, you can just leave the setting alone.

  • L'AdairL'Adair Posts: 9,479
    Richard Haseltine said:

    You don't have to fully hide the items, just turn Visible in Simulation off. That way you don't have to unhide before rendering, you can just leave the setting alone.

    LOL. I need to use Bullet Points more, me thinks, make my verbose wall-o-text more readable, like this:

    L'Adair said:
    [snip]

    There are two ways to make unnecessary objects not visible:

    • either hide them in the scene, (you don't see them in the viewport or render,), or
    • uncheck "Visible in Simulation" for those items.

    You can select all the items to hide in the Scene tab, then select all of them in the parameters tab. Type "visible" in the filter field above the right column to isolate the visibility options. Both Visible and Visible in Simulation should be among the isolated options.

    [snip]

    angel

  • Richard HaseltineRichard Haseltine Posts: 100,781

    oops, I thought I had checked. Sorry.

  • L'AdairL'Adair Posts: 9,479
    Richard Haseltine said:

    oops, I thought I had checked. Sorry.

    No problem. I'm the wordy one!

  • jukingeojukingeo Posts: 711
    Richard Haseltine said:

    You don't have to fully hide the items, just turn Visible in Simulation off. That way you don't have to unhide before rendering, you can just leave the setting alone.

    Hmmm, there are things I turn off in the render as well, so I can reason more with L'Adair on this one.  If I hide it, I know it is 'off'.

    Thanks!

     

  • vf1sveritechvf1sveritech Posts: 15

    Mesh Smoothing slows many of my simulations down when Posing; sometimes by a lot and sometimes not too noticably. I always turn it off for the simulation and then turn it back on if necessary.

  • cajhincajhin Posts: 154

    Play with Simulation > Collision Mode, and Collision Iterations.

    Some items need "Best / 4", some "Better", some work well enough with "Good / 2". The speed difference is significant (easily 4x)

     

  • jukingeojukingeo Posts: 711
    vf1sveritech said:

    Mesh Smoothing slows many of my simulations down when Posing; sometimes by a lot and sometimes not too noticably. I always turn it off for the simulation and then turn it back on if necessary.

     

    cajhin said:

    Play with Simulation > Collision Mode, and Collision Iterations.

    Some items need "Best / 4", some "Better", some work well enough with "Good / 2". The speed difference is significant (easily 4x)

     

    So turning off the collission and smoothing will significantly increase the simulation speed?   Would this have any affect on the outcome in terms of pokethrough issues?

  • juliano.cruz_97bea1265ejuliano.cruz_97bea1265e Posts: 76
    edited December 2020

    Sorry for my ignorance on the subject ..

    I recently bought a hair with D-force.
    I always render still images... is it necessary to simulate in 60 or 30 frames for still renders?
    My computer takes hours just to fit the hair in each pose that I want...

    Post edited by juliano.cruz_97bea1265e on
  • jukingeojukingeo Posts: 711

    juliano.cruz_97bea1265e said:

    Sorry for my ignorance on the subject ..

    I recently bought a hair with D-force.
    I always render still images... is it necessary to simulate in 60 or 30 frames for still renders?
    My computer takes hours just to fit the hair in each pose that I want...

    I know this is an older post and I am sorry for not being here, in the forums, as often.   But there is a way to speed things up if you are doing a static pose, as using the timeline is always time consuming.   So, there is a faster way if you just want hair or clothing to 'drape' over a fixed figure form.  Usually in a standing position.   If the figure is laying down or sitting and the clothing cannot be formed around the body, then you have not choice but to use the timeline (again this is in general, as hair wouldn't be affected as much if someone is sitting or laying down, however, if the hair is very long, you will probably want to simulate it pooling on the floor if your model is laying down).    Ok, so if you are going to have a standing pose in which the clothing and / or hair can be posed away from the body (usually by default), then here is what you can do.   Please referr to the attached:

    In the Simulation Settings Tab, go to Start Bones From Memorized Pose option and set it to "Off".  Then under the Frames To Simulate option, set it to "Current Frame" as shown.  This will give you the options below it and the one you are interested in is Stabalization Time.  You can increase the time figure to allow clothing or hair to "settle down" better.   I usually set this to 2 or 3 depending on how far clothing (or hair) has to drop.

    Keep in mind that the hair or clothing cannot clip through items when you set the simulation.  If it does, it will explode.   I personally VERY rarely use long dForce hair.  I have used short hair, but that generally doesn't need to be simulated.   I mostly do clothing and this method for quick standing poses cuts down on the simulation time drastically. 

    I hope that helps you out, but again this is an older post, so you probably have seen this option already by now.

    Regards,

    Geo

     

     

     

     

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