Biped Tutorial

Sam Crowe

Description

Positioning biped into your character and getting ready to add the physique modifier. CHAPTER 1 This tutorial is geared toward beginner and intermediate users of Studio Max and Character Studio. A few words about this process… Keep in mind that there is no “perfect” way of doing this. What I am about to show you is simply one of many ways to get the same result. Once you go through this tutorial, I suggest you experiment with various techniques and find out what works best for you. Take your time and learn as you go. Be prepared to rework areas over and over until you get the desired result. In most cases, you may not see errors in your mesh until you’re on your final step, or well into the animation process. I have chosen to use the model pictured above as a base for this tutorial; mainly because it contains a lot of the “situations” you may run into when setting up (rigging, physiquing) a character. There are also areas in this model that will require some reworking during the physique process. As with many character models, not ever joint on the mesh will deform correctly, so there will be times when you have to go into the mesh and make adjustments, by either adding or subtracting verts. This tutorial is GAME based, meaning that it uses the rigid physique settings. A lot of what is talked about in this tutorial can relate to the Deformable(smooth) physique setting and I encourage you to experiment with both so you can see the differences in ...

Informations

• Publié par: Nesheg
• Nombre de lectures: 15
• Langue: English

Extrait

Positioning biped into your character and getting ready to add the physique modifier.   CHAPTER 1 This tutorial is geared toward beginner and intermediate users of Studio Max and Character Studio. A few words about this process…   Keep in mind that there is no “perfect” way of doing this. What I am about to show you is simply one of many ways to get the same result. Once you go through this tutorial, I suggest you experiment with various techniques and find out what works best for you. Take your time and learn as you go. Be prepared to rework areas over and over until you get the desired result. In most cases, ou ma not see errors in our mesh until ou’re on our final step, or well into the animation process.

  I have chosen to use the model pictured above as a base for this tutorial; mainly because it contains a lot of the “situations” you may run into when settingup (rigging, physiquing) a character. There are also areas in this model that will require some reworking during the physique process. As with many character models, not ever joint on the mesh will deform correctly, so there will be times when you have to go into the mesh and make adjustments, by either adding or subtracting verts. This tutorial is GAME based, meaning that it uses the rigid physique settings. A lot of what is talked about in this tutorial can relate to the Deformable(smooth) physique setting and I encourage you to experiment with both so you can see the differences in deformation and outcome. I should also note that, if a lot of the terminology used here is vague or not understood, just hit the F1 key on your keyboard for the Max Help section and look on your own for definitions of terms. There is also a help section for character studio, but it’s sorta hidden from view, you can access it by selecting the help function from the menu and then selecting, ADDITIONAL HELP (see diagram below) or hit the 3dbuzz forums, somebody will be happy to answer your questions. We all had to ask at one point ☺   Pictured below is how ou can access the character studio help files.

    About shortcut keys. For the most part, I’m not going to be using shortcut keys in the tutorial. I have mapped my own personal keys and I’m pretty sure they don’t match what you may have. So I have included screen shots of the menu commands to help you along. First, it’s pretty important that you set the scale of the character. Meaning, what is the system of measurement used in the game engine. For most cases, it’s usually in Meters. A human that is 6.2 feet is roughly 2 meters tall. I have created a wire template you can use to gauge the size of your character, you can download it HERE. INSERT LINK HERE.  

  This scale template is set for the meter scale system. For instructional purposes, we will be using the meter scale system through out this tutorial. 1.   Open your mesh file 2.   Merge the scale template into your current scene When you merge an object into the scene, you maybe presented with a popup dialog that states something about the scale differences. This is because the scale system (units) that you created your character at does not match that of the scale. If this is the case, check the adopt new file scale. This will change your scale settings to match those of the merged file. If you are not presented with this message, don’t worry…that’s a good thing ☺   If your character is too big, you may not see the scale template. Use the select by name dialog to highlight your scale template, or start scaling down your character mesh so it roughly matches the template. You will want to center you character in the world. Meaning you have CENTERED the pivot point for the mesh with the co-ordinates of 0,0,0. DO THIS: 1.   Select the hierarchy button 2.   select the AFFECT PIVOT ONLY button 3.   click the CENTER TO OBJECT button. 4.   DESELECT!!! The AFFECT OBJECT ONLY BUTTON 5.   click once on the SELECT AND MOVE button 6.   Then right click on the SELECT AND MOVE button 7.   In the pop up dialog, you want to make sure that the highlighted areas all contain zero’s. This will center your mesh, based on it’s pivot point to the center of the world in max. Once done, close the dialog box.

  We can’t have our character just floating around in space, so we need to decide where his/her/it’s feet will be. This should be the same for ALL characters that are exported. With the Scale template, you’ll see he is standing on a wire box, this is where the feet will contact the ground. Use that as your guide for foot placement. This will help keep the feet from penetrating the ground plane or hovering above it when actual animation is applied. You can move this ground plane after you center your mesh, but try to keep it in the same place for all your characters. The Scale template is a group, if you wish to move the lower plane, simply OPEN the group and then move the Ground plane as desired. Once you are done, simply close the group. Before we move on, select all of your geometry and put it into a named selection. This way, you can easily select your geometry, if it’s hidden or frozen, with out having to go through various menus.

  If you need help with using named selections, look in your manual or hit F1 for online help and do a search for named selections.   Ok, check list time: •   Your character is scaled correctly •   Your character is centered in the world •   Your character has some sort of guide as to where the feet will be placed.   CHAPTER 2. BIPED TIME!!!!   CHECK LIST: •   In the front viewport, your character is facing towards the front •   You have successfully completed the above check list   DO THIS: 1.   Click on the create tab 2.   click on the systems button 3.   click on the BIPED button and STOP!!!!

 Ok, before you get too click happy, let’s go over what’s happening in this panel. Not a whole lot really, but there is one very important section that can be useful to you. The ROOT NAME section. This is where you can NAME the parts of your biped. So, instead of there being BIP_01 etc etc, you have something like SNOTPILE_01. So essentially, all the prefix names of your biped bones can have custom names. Now, if your game engine supports sharing of bones for character meshes, you may want to keep a single name or use the default. BIP.  

Don’t worry about the section below root name, we’ll cover that later in a separate panel.   Now, it’s time to click… In the front view port CLICK AND DRAG, starting from the very bottom of your character’s feet. And drag upwards. Character studio draws the biped from the feet upward, so to keep from moving stuff everywhere, start at the feet and drag up to the top of the head. As you drag, you’ll see your selection indicated by a bounding box, use that as a rough guide until you reach the tip top of the head. Once ou’re done, ou should have something that looks like this:

  Now it’s time to start positioning the biped so all of its components lie inside your mesh. In order to do this, you need to be in FIGURE MODE!! 1.   Select the bip01 ,or any bone of the biped object from the named selection dialog box. 2.   Go to the motion tab and click on the figure mode button

  Figure mode is where you set the DEFAULT pose of your character and where you make adjustments to the biped. You CAN NOT create keyframes while in FIGURE MODE. So, if at some point down the road, you’re animating your character and can not generate keyframes…chances are, you’re in figure mode. The pos that you see now, is the current default pose of the biped. Just to make sure you understand the difference, let’s do this : 1.   Deselect figure mode 2.   grab any joint and rotate it, move it what ever you wish. 3.   Go ahead and move all the joints around if you want to. 4.   Once you are happy with that, select the figure mode button. 5.   BAM!! The biped has now snapped back to it’s original pose. Figure mode is a great way to temporarily revert back to the default pose for any adjustments you may need to make.      

Go ahead and select figure mode again. The main goal is to put all of the biped bones into the mesh so they are just barely showing up through the mesh. But before you do that, you need to move the entire biped. Moving the biped is done through the COM, or center of mass object, sometimes referred to as the bip1. To move the COM, ou have 3 icons to chose from, called BODY keys.

  By using the body movement keys, move your biped inside the mesh of your character. Place the COM in the center of hips by manually moving it, or you can try a familiar method… Since your mesh is already centered in the world, you can do the same with the biped. Make sure you have the COM selected and right click the select and move tool as you did previously to center your mesh. Zero out all the co-ordinates. You’ll notice that you can only zero out the X and Y co-ordinates, this is because you do not have the body vertical button selected. Simply select it and it will allow you to zero out the co-ordinates. Now your biped should be centered and the COM should be rett close to where we want it.

 

  Now lower the COM just a bit so the pelvis is just below the crotch area. PHEW!!! Here is where it starts to get in depth…. How many spine segments, how many fingers, how many toes? How many neck joints… Well, the answer to those questions really depends on your character. Just remember this, the more bones you have, the more “stuff” you’re gonna have to animate.So try to keep it as simple as you can. Let’s get rid of some screen clutter. Remove those damn selection brackets. Right click on the name of your view port, upper left of every viewport and select configure. Then in the pop up dialog, uncheck the USE SELECTION BRACKETS. This will remove those annoying selection brackets for that window. Now the ALT X!! By pressing the ALT and X keys, you will ghost anything you have selected. This makes your selection transparent. This is very handy when using biped. You can ghost your mesh and see inside it while you try to position your biped. Depending on your system specs, working in ghost mode may slow down performance. You may want to ghost only certain parts of your mesh as you get to them. You can always exit ghost mode by selecting the mesh and hitting the ALT X keys again. You should have your mesh in a named selection, if so, select it and hide it. Now, select all of the parts of the biped and created a named selection for it as well. Now, just go to your named selection pulldown and select your mesh. This will unhide your mesh. If your entire mesh is Ghosted, and it’s frozen, you can still “see-through” the mesh but it’s in a frozen state, meaning you can’t select it.                      

How to freeze your mesh: 1.   Select the display tab 2.   expand the freeze panel 3.   with your mesh still selected, click on the freeze Selected button   Check list: •   Understand what Figure mode is •   Understand what the COM is •   You have centered your biped, using the COM to the world’s center. •   You have adjusted the COM so that the pelvis is roughly in the correct place between the hips of your mesh. •   You know how to use named selections   You know how to use GHOSTING(Max referrers to Ghosting as “see-through”) • •   You know how to remove those damn selection brackets. •   You know how to freeze your mesh   With your mesh still selected, freeze it.

                           

 

 

  Let’s start with the spine. First, you need to decide how many spine segments are needed. The number of segments will vary depending on the length of your characters torso and how much motion you want in this area. For the most part, all humanoid figures have an ‘S’ sha ed s ine.

  As seen in the image of the spine, the spine curves in and out at various places, It is important that you match this curvature as close as you can so you’re character’s movement, as far as breathing, bending and twisting are animated much like a real spine would. Since you don’t have Rib bones, your breathing animation can be created by using the clavicle bones and slight spine movements. How much movement or degree of freedom does the spine have? Well…that’s easy, stand up and bend and move to see for your self. Try to bend sideways without turning your waist, your ribs get in the way, try bending forward and backwards. Obviously, there isn’t as much freedom of movement in your spine as say…your elbow. The spine bears a great deal of weight and it just wouldn’t make much sense if it was flopping around at each segment., unless you’re a snake. So for my example, my character doesn’t need a whole lot of spine segments, she can move and perform a wide range of motions with onl 4 se ments.

           

 

I have ghosted my pelvis bone and created a named selection for the COM. This way I can see where my COM is and I can easily get to it for animation with adding a named selection.

  Make sure you’re in figure mode, for the most part, from here on out, we will be in figure mode. Make sure you are in local mode Scale our elvis so the le bones move into osition where the should be.

  Some bones can be moved while other can’t. A great example is the spine. In most cases, the parent of the chain of bones can be moved, but the children can’t.                                

Do this: 1.   Grab the Bip01 Spine and move it out of the mesh, now try and do the same to any of the other spine segments…biped will not let ou. You can scale, and rotate them, but movement translation) will not happen.

  2.   This hierarchy is very important to remember. Especially when you’re trying to position your biped into your mesh. 3.   Go ahead and position your spine segments in the ‘S’ curve shape and be sure to scale them accordingly.  

 

  

 

    You’ll notice that I’ve scaled the biped bones...there is a reason for this.

First off...BIPEDS ARE NOT MENT TO BE PRETTY!!!!!!!! These are bones, and the physique modifier works by VOLUME (this will be evident later on) so it’s important that you scale your bones to match your mesh as close as possible with out completely penetrating the mesh.. By doing this, you will save your self a lot of time later on. It may look funny to you once you’re done, but remember, it’s the mesh that deforms...not the bones. UGLY LOOKING BIPED BONE ARE COOL!!! Wait until you do a quadruped ☺   NOTE: The neck bone is part of the spine, so be sure to position it as needed to finish the curvature of the spine. Now character studio realizes that things are starting to get pretty cluttered now so, thankfully the biped is color coded, default being blue and green. If your character is symmetrical (proportional on both sides) then you really only need to work with half of the biped...no problem. Simply hide one of the two sides of the biped. Don’t worry, if you need all of them visible again, simply use your named selection and they will appear. Ok, I’m going to hide the blue half of my biped, which half you hide, is totally up to you. But one half must remain visible.

  With half hidden, let’s focus on the arm. By using the move and rotate tool, I have position my clavicle bone and upper arm bone roughly where I want it. But it’s TOO SHORT!                                                                      

So instead of using scale, we use the RUBBER BAND MODE. When working with positioning of your biped, it’s better that you work in the LOCAL system. Local basically means that you’re working with the co-ordinates of the selected object instead of the co-ordinates of the world. DO THIS: 1.   Make sure you’re in local mode 2.   turn on the rubber band mode 3.   select the upper arm bone 4.   Use our move tool and move the arm bone.

  Rubber band mode allows you to stretch your bones, much like a rubber band, this in turn, does NOT affect the children bones. IF you used the scale tool, to scale the bone, this would also affect the bone below it, causing it to extent to far out. Rubber band mode does not work on all bones; it’s used mainly with the arms and legs. Go ahead and position your upper arm bone so it’s end rests just above the elbow of your mesh. Now, adjust your forearm bone so its top rests just below the elbow of your mesh. Don’t worry about the hands; we’ll come to those later. This is a good point to talk about a big misunderstanding about placement of the biped in the mesh. Your bones do not have to be exactly at the center of your mesh. In other words, in my arm the bone doesn’t fit exactly down the center of the arm. Not a problem, it’s the joint area that I’m most concerned with because this is where all the deformation takes place. You can make adjustments in your physique modifier for proper deformations if you can’t get the placement just right. Using the same techniques above, position your leg bones so they are placed correctly in the mesh. Once you get your arm and leg bones in place, use your named selection pull down to unhide all the bones you’ve hidden. Now here is the nice part…If your me sh is symmetrical, you can cut your time in half by using the copy and past posture commands. DO THIS: 1.   Select the arm and leg bones that you have adjusted. Don’t forget the clavicle bone 2.   click the copy posture button 3.   click the aste osture o osite button

  This will mirror all the changes you’ve done on one side to the other side.