Houdini KineFX 101: Tutorial One - FBX Import, Rig Pose, Skeleton Blend

with eugenie 18.5 character rigs and fbx's have been moved to the stops level in the first course of this series i'll be going over the basics of kinfx and side reading 18.5 and how it can be useful in many ways to start the way we import fbx's is now completely different to start we're just going to drop a geometry node and then we'll hop right in that and then the way we import fbx is now is through fbx uh through through kinefix so there's fbx character import fbx skin import um an fbx animation import fbx character import kind of combines all all of these um so really this is the one you'll be using most of the time the others is kind of there if you want to isolate stuff so we'll import it and from the get go there's nothing plugged into it so we don't see anything so i will go ahead and put in one of my just this is just the base model i downloaded from miximo um so let's open it up and you'll see right away we are seeing the uh rest model and we can see these bones inside of her and one thing we'll also notice is that um it came in at the right size which is great because we have this little convert units button um which without it it would import i think she's about uh 200 meters high in this one so that would happen to me a lot and it would be annoying having to go real scale everything and bring everything down so it's just a nice little thing they have this automatic um conversion of units so she should be the right size okay so let's break down what these three little outputs are so the first one is your rest geometry so this is just the mesh and then the second one we got the capture pose which is essentially the skeleton at its rest position and then the third input we don't actually always need but this is if there is an animation or anything on your on your fbx and this is your animated post so this is basically your skeleton but moving re-highlight this and i bring in something that is animated so this is her room with dancing we'll see this uh this skeleton and we'll see it move if we jump through the the timeline and uh we'll notice that nothing's really happening with the base mesh um and that's because each of these outputs don't really do anything to affect the model so we actually need another node for that we need a bone deform node i'll drop that down you'll notice it has three inputs which are actually these exact three uh outputs so it has the basically the geometry you want to deform your model with all the painted weight attributes and everything and then you have your uh rest points which is the skeleton at rest and then you have the deep form points which is your skeleton animated so if i move and i plug all three of these in you'll notice we have this little room with dance animation and i'll go ahead and i'll tie this to the timeline so awesome so we can import animations and if we wanted to on the timing so there's if we wanted to make this slower or make the animation faster on the fbx character import node we have this timing tab and we can do it by time or are by frames um and let's say i wanted to make this twice as fast i just input that two now she's going twice as fast let's just make this drastic so you can see that's ten times as fast um i can make it like half speed now she's slow roomba dancing um so yeah so that's how you can kind of play around with stuff you can change the animation start time by default it's linked to the first frame you have so i have mine set to 1 right now if i change it to 10 then the animation is going to start at 10 i actually think i might need to change this by time yeah okay so you can see now it starts at 10 15 20. all that stuff so that's great um but now i'm going to go back to just the base mesh with no animation and from here i'm going to show you how we can control fbx's that have skeletons but no animation basically most of kinfx revolves around one i mean i wouldn't say revolves around it because you don't really want to use this to animate but um for posing and for just right out of the box the node rig pose is going to be one of your most used nodes in this scenario and what we're going to do is we're going to be plugging this in from the animated pose into the deformed points and you'll notice nothing is really on this node we won't want to be controlling this node from the parameters we want to control this node in the viewport and essentially what it does is it allows you to rotate and transform the joints of your skeleton mesh so you can do things so if i select this elbow joint and i start moving it you'll see that all of a sudden we can deform our mesh by the skeleton without having to do any type of setups or anything um and this is essentially uh what's considered fk animation which is where according to the hierarchy you'll see we have this new hierarchy view if i was to move the right shoulder then the right arm the right forearm and everything down this list would rotate along with it you'll see if i rotate this everything's moving downward but if i say rotate the finger it's only going to rotate what's down the hierarchy of this and the hip is usually where you'll control any type of master movement as you can see i can move uh her whole body here if i want to move the leg up this down so this is a really quick way of just immediately getting poses out and you'll notice as you move things in here we'll get these added little parameters um so if i move the foot that i hadn't already moved you'd see well okay well this is seven now so i have transformed seven joints and now if i click on another joint that i have not added yet it's going to add another um transformation and the nice thing about this is you can go through these and you can either just clear the whole thing out so if i hit the clear button then we're back to no transformations but let's say i wanted this to um see i don't like these because these numbers are like incredibly small and they bother me so i'm going to zero these out and then i'm going to change the rotation to minus 45 because i only want it to be rotated 45 degrees and so you can you can use this directly if you want to but you do have to just kind of select just kind of to touch it any of the joints to get them up on here one thing that you want to note is that typically with rig pose you don't want to be doing much transforms so you want to i mean when i say transforms i mean literally like the position rotations awesome work perfectly fine but as soon as you start transforming things um there's no constraints on this rig pose so you'll notice things kind of just start deforming and just not not some great looks if you accidentally touch some of the translates or anything you can control middle mouse button click to zero them out i'm saying what the rotations are uh any of that stuff so what can we do um with this um because like i said animating on the rig pose is usually not what most people i mean you definitely can do it and there's definitely been times i've done it i'm not saying don't do it um but i'm saying usually it's not the ideal way to go about um animating uh these fbx characters so one thing i like to do a lot is so let's get a pose here so i'm just gonna put her arms down and let's say i wanted to have her look off to the right one thing you'll notice about rig poses is that they're procedural so they kind of stack on top of each other in local space so this one i can just rotate her neck and on this one i'm gonna go call it rotation neck raw and then on this one i'm gonna call it arms down and you'll see that if i plug this one just directly into the base her head is still going to be exactly the same everything we edited on this node is still going to be applied but we can just take this off so it's maybe to maybe show you a better way of this um i'm gonna rotate the neck on the arms down rig pose oh get this out of here and then i'm going to add this on top and you'll see that this actually this rotation adds on to the other rotation so we can keep rotating on this and then this will still be applied after that one so the nice thing about this is that we can use this to create um some nice poses and i'm going to just delete this neck transformation so let's say i wanted to make her head go left and right and i didn't want to i essentially didn't want to animate using the rig pose and just have to do that uh animate all three uh rotations every time i wanted to rotate her neck so i'm gonna go ahead and call this r [Music] l for rotate left and i'm just gonna alt drag to create another one and then i'm gonna go ahead and hear this and drag her head that way so i have a left and a right and what i can do now is we have this other note which is called skeleton blend and this is different than a blend shapes or a sequence blend or anything like that because this kin effects um in rig pose works in local space and as well as world space but um instead of blending directly between the two positions it's going to kind of still maintain the hierarchy and the parenting values so we can go ahead in here and we can plug these guys in and then right now it's set to one which means that it's going to take the input from the the b input so the one and then zero would be taking from this input so we'll notice that uh i call this this is a terrible naming structure actually um rot right change this to rot left so it's less confusing um and so we'll notice she's looking right because i have it coming into the one and now if i blend to zero you can notice she'll be looking back and forth and now the nice thing about this is we can use a lot of this so i'm gonna go call this look right left and then i'm just gonna create another null put these guys in here and then have this as kind of its own little thing so we got this guy in here now and then if we wanted to we could just copy and paste this whole setup and we'll take this again and i'm going to zero these out for right now and then i'm just going to go ahead and i'm going to create a rig pose that we can pose on so i want one where her legs go up and again this is just for example um this is uh just trying to show you how you can use this um so i'm gonna call this legs up and on this one i'm actually going to just delete one of these guys and um replace this one so we actually want the original coming in through the first pass so we can essentially say um don't do anything to the legs if we're at a value of zero but if we're at a value of one we want the legs lifted and this won't override anything back here um so we can use these to continuously um adjust our model we can animate these values and um they can look great um and as far as just the basics uh i'm gonna stop this video here and in the next one i'm gonna go over um some more so thank you for watching

Channel: Parker Coleman

Views: 7,670

Rating: 4.9433961 out of 5

Keywords: Houdini, KineFX, kine, fx, rigging, fbx import, fbx, rigging in houdini, rig pose, rig, pose, skeleton blend, fbx character import, kinefx 101, class one, basics, houdini 18.5, rig vop, fullbody ik, ik chains, procedural rig, rig hda, houdini digital asset

Id: 7vg0bnc5R7Y

Length: 14min 20sec (860 seconds)

Published: Mon Jan 18 2021