How to CREATE LOOPS using MOTION CAPTURE and Motionbuilder - 3 methods

hey everyone and welcome to my youtube channel this is season one episode one and for this very first video i wanted to share three different methods of how to extract and create a loop using motion capture data and autodesk motionbuilder so the first method is going to be using the story only the second one is the traditional use of layers and poses and the third one is a method that i call personally the 50 50 you'll understand why in a minute all right let's get started so i've set up the scene in motionbuilder with one character as well as some mocap data that i have found online i'm gonna do a separate video on where i found the rig where i found the mocap so i want to share some good tips when it comes to finding uh quality contents online when it comes to both characters and mocap so when i start working on a scene like this having in mind i'm gonna have to extract a loop from that content um i usually focus on three main things the first one is the alignment so i usually work from the front camera so the first thing i do is i usually rotate my character so that it's following the positive z axis which means it's always going to work towards the camera so towards me right the second thing is the position i'm uh i i like my character to be centered in the scene so i'm gonna move and translate that to that clip so that it starts at the zero zero zero uh scene position and the third thing is obviously the data itself so i start analyzing uh which part of that data is going to be usable as a loop so i observe the pose observe the speed because you don't you you want the speed to be as constant as possible during the loop uh so this is uh this is what we're gonna do now so i'm gonna need to plot the data to my control rig before i can even start editing anything right so just go ahead and do this now and then we'll move to the story to adjust what we want so go ahead and create a new character track onto your story select your character insert the current take go ahead and turn the story on the first thing i want to do is from that camera the front camera make sure my character is facing me so to do this just click on that i icon here that turns the uh like clip edition actually the ghost uh of the clip make it visible and start rotating the clip on the y-axis so that it's almost uh facing you right and if you want to have something uh perfectly aligned then you're gonna have to switch to rotation here and input a data that is gonna be um a perfect axis right so in that case it is going to be minus 90 and then uh we're sure that uh first frame and and last frame are perfectly aligned and this is uh something you can confirm by so this is uh the clip trajectory so uh well the trajectory it's actually a direct line uh drawn from the end position and the start position what i'm gonna do next is the uh repositioning of the clip just switch to translation and then right here just input 0 0 0 and then you'll have a character starting at the center of your scene and then the last thing as i've mentioned was um picking the fragment you were really interested with so so we have a lot of data to work with here so it's just uh you know your choice to uh find what is uh best for your needs since we have a lot of data i suggest we take the most out of it and create for example a double cycle loop which means we're gonna have four steps total right so the first thing we're gonna do is to find a start pose right because you want your loop to start at a certain frame so of course any frame can become the the first of your clip but i suggest you always pick a passover pose which is a pose like this meaning you have one foot flat on the ground and then the second leg is passing the other one i usually work with passovers for two reasons the first one is because the pose is easily recognizable which means you're gonna you're not gonna struggle to find the next passover further later in the clip and the second reason is because it's a really good pose to blend from and to because you reduce by half the potential food sliding since you only have one on the ground what i'm going to do now is to split my clip so that this frame becomes the first frame of my loop so i'm doing this by using the result tool this one so if you click on this having your clip selected it's just gonna split it in half the keyboard shortcut for this is alt r and then i'm gonna just scrub my animation and find the like second next passover which is here and i'm doing the same thing i just split my clip with alt r this time [Music] to make sure that these two frames are similar and now this is the data i'm gonna work with which means right now i don't need this one so i'm deleting this and i don't need that one uh to avoid altering the default take you have what i'm going to do is just create a new tag here you can copy the contents it doesn't matter because we're gonna erase it anyway and then you can reframe that clip to your animation and then for the sake of having a clean scene what i'm gonna do is just i'm gonna drag by that character so that my first frame my first loop frame is that the zeroed out so i'm gonna put my uh so select my first frame here and i'm just gonna input here on a keyboard three times zero and then i'm gonna be able to uh move that clip back to the zero frame as well so that we have something both zeroed out in time as well as in position and rotation since we've made sure before that our character was following the positive z axis okay so here we are with our isolated fragment the next thing we want to do is to start working our way towards converting this into a seamless loop so here is how it looks to use the story to do so so what i'm gonna do is i'm gonna start by duplicating that clip and paste it after so go ahead and do this select your clip control c and then move to the end of your current animation paste it ctrl v and then reframe your take so that both clip are part of it so right now what we've just done is just we've duplicated the clip obviously it's repeating which means the position also resets right so the first thing we're gonna have to do is to uh fix this which means that the first frame of the second clip is gonna have to match these last frame of the first one so you have uh two options to do it the first one the most uh traditional one would be to use the uh match tool here but using this tool you have no way to isolate axis so if you want for example to just match the z-axis there's no way you can do it with the match option so make sure you select your second clip and then your ghost mode is turned on and then drag your clip so that those two markers which are technically so this this is the current frame of your clip and this is the last frame of the first clip so you just have to make the match like uh you know it's not going to be perfect but as much as you can and then you can observe what you've just done by so since we're on a passover then the left foot is going to be our reference point to make sure that there is no foot sliding obviously there's a cut in the animation because the the frames do not match but what's important here is to uh to not have any foot sliding forward so i think it looks uh it looks great right so right now if you look at your animation what it does is you have obviously a longer loop or longer animation sorry because it's not looped yet but what you have here is a cut in the animation because the two frames do not much and this is what we're going to do now so just position your um actually doesn't matter but i usually set my marker here so my cursor sorry in between the two clips and i'm gonna be able to start uh the blending operation using the story mode so uh if you drag if you select your first clip here and then you drag on uh you put your mouse on the bottom handle here your cursor is gonna change to that uh light cross here and if you drag this you're gonna actually met it so that the last frame of that clip still influences uh like overlaps onto the next one so do this for the first clip and then do the same thing for the second clip but that way just drag it backwards in time which means actually they're gonna it is a typical a to b uh blend right so what you've done john is that you you smoothed out the transition between the two clips so that the actual transition happens not in one frame but in uh i have like four and four i think so eight in total um if you want to do this even more uh so to have even better results you can select both of your clips go into your uh properties and then under fade in and out select smooth both for fade in and fade out interpolation so the last thing i need to do now since i have duplicated my clip is to get rid of the extra data you could stick with that long loop it's fine but i want to keep what i had previously planned which was having a double cycle so i'm gonna just gonna find in my first clip uh the the middle pass over and then i'll do the same thing for the second clip i think it's gonna be this animation i'm just gonna observe the yeah it's going to be this one this one here alt r to [Music] cut and if you remember since we've duplicated this clip then this frame and this frame are the same right because they're a copy of themselves i mean this one is a copy of this one so uh what i what i have to do now is just get rid of that first clip that last clip just select my two clips drag them over to the zero frame and then reframe my current take so that just these two are taken into account and i've just created myself a nice loop right so obviously right now we have made sure that the animation here i mean there was no cut in the animation but we're still going to have to uh work on on on some things right so in that case that would be the hand here so there's a position there's a difference in position right during that clip uh it's uh it's much more behind the body here it's much more exposed and then see in a couple of frames here it just uh it it just changes so this is something uh we would have to work on as well as this left foot here having a rotation flat on the ground but this is not something i'm going to focus on right now because it's a another topic right the goal was to create a loop and we have it so uh the very last thing i need to do because right now the contents is still only part of the story is just to plot it to my character so you can do this now hit animation and then plot all plot and right now on your control rig you have a nice loop [Music] all right so i'm back at the square where i had previously uh isolated the fragment i wanted to work with my character is already facing the positive z axis and the first frame is set to start at the center of the scene uh right now the rest of the work is going to happen outside of the story so we're going to have to plot the story contents onto our control rig right so hit animation plot all and then plot and then you can deactivate the story and hide it by the way um i don't know if you've ever noticed but it seems like on if you have a computer that is not that powerful having the story visible might affect performance so now that we have our data uh retargeted and plotted onto our control rig the next step is to make sure that the start frame and the end frame so the poses actually match right so you're gonna have to pick uh either of them uh i'll let you be the judge of uh telling which one is the best i'm i'm personally gonna take the the the start frame so i'm just gonna create a pose of uh that start frame so in your post control just do this create a new pose here create a layer key your layer so that this pose doesn't get affected and then set your cursor at the end frame and we're going to be able to paste that pose but before we do this there's a couple of things i wanted to explain regarding these parameters over here so by default you should have them like me so translation and rotation should be turned on and what it means is that motion builder when you're gonna paste the pose motion builder is going to perform what they call a pose matching which means you're going to paste a pose using a reference point in our case i have selected the hips effector but the translation and rotation are gonna be preserved which means that if i created a pose facing forward and then i want to paste that pose onto a frame where my character is facing backwards for example i would paste the pose but my character would still be pacing backwards and then the current translation would be maintained right preserved so in our case we want to do something slightly different than a full pose matching we want to the rotation to be preserved and we want also the x axis to be preserved so that our character is not for example at start frame here and from here right obviously i'm over exaggerating so that you can understand what i mean by this so uh what we're gonna have to do is just to turn off the pose matching for rotation as well as for the x translation component and then if you double click on the pose to paste it and then key it here you can see that your start frame and end frame are the same so the poses do match except for the z translation component right because obviously we do want our character to keep moving forward awesome so this technique is uh perfectly fine it's probably the most commonly used it is really fast really easy to use but in my mind it's good only when your first frame so first the start pose and end pose are actually similar the moment where they start being really different because of many reasons uh you're gonna have a lot more work to do in the layer to just compensate the change you're gonna automatically input when you're gonna paste a post that is uh really different right uh in that specific case i would suggest using the technique we're gonna we're about to see together which is similar but still enables us to kind of go halfway uh in between the extreme which is start pose and then pose [Music] alright so to explain this one i'm actually gonna mute the layer i've been working on and create a second one which is the one i'm gonna be working with to demonstrate how this technique works now it is pretty similar because we're gonna have to create a pose and then paste it but in that case we're gonna have to do this twice on the first frame and on the last frame uh to demonstrate the uh power of this technique i'm actually gonna alter one of the poses which is gonna be this one so uh sorry on this layer i'm just gonna show you i'm gonna introduce the difference so i'm gonna key that one so that it stays the same and over here i'm just gonna like do some weird stuff on my character so that you know the pose is uh it's pretty different or more than it was something like this right it would be worse to actually use the first technique we've seen a while ago to compensate that change so this layer here actually this one i'm gonna delete this one i'm just gonna rename and uh post difference and i'm gonna create a new one which is the one i'm gonna be working on with the uh with the poses so uh let me delete this post that we start fresh so um i'm gonna create a pose uh on the the first frame and as well as on the last frame and what we're gonna have to do now is just paste the pose we've created from the first frame on the last frame and vice versa the parameters are gonna have to be the same as previously so we want to keep the rotation as well as the x component of the translation so just paste the first pose on the last frame and paste the second pose on the first frame so right now obviously you still have differences but then the trick is like if you change the weight of your layer and set it to 50 then magically you have a perfect match so how it works is you reduce by half the changes you've introduced by pasting the pose the one pose is now halfway towards the second po the other one which means that if your character was for example on the first on the first frame bend forward and then our last frame was really straight then your first frame is going to be halfway towards the first and the last and the same thing for your last frame which means then they're they're they meet at some point which is the halfway point and and this point in our case is a pose and this is the pose we get when we do this operation on the first frame and on the last ring so it's good to have in mind that you've now altered uh more the animation itself by saying that if your first pose was like let's take the example from uh earlier uh really bend forward slightly lower and then a normal pose for the the end pose then your um your clip would be halfway towards these poses but then you propagate the changes during your entire animation so this is why it works really good when you have uh poses that are really different from start to end and there you go my three different approaches to quickly and easily create seamless loops from mocap if there is another method that you're using yourself please let me know in the comments if there is something you would like me to cover or to get back to for the story the layers the post controls please let me know as well in the meantime thank you for watching have fun stay safe and see you soon

Channel: Matt Courtois

Views: 1,518

Keywords: motion capture, motionbuilder, mocap, tutorial, animation loop tutorial, game animation, gameplay animation, motion capture animation tutorial, autodesk motionbuilder, motion editing, create loops

Id: GQpwmI8s9Bw

Length: 22min 38sec (1358 seconds)

Published: Sat Oct 17 2020