Rigging and Skinning
Max vs. Maya
To start the practical aspects of this project, I intend to take the research I have completed and put it into practice. First I am going to rig and skin a model I have generated using Autodesk’s Character Generator in 3DSMax, detailing my process as I go, as well as weighing the pro’s and con’s of the software, and summarising what I have learned whilst using it.
I will then move to Maya, and using the same model, I will rig and skin it in that software, following the same procedure as above for detailing my experiences.
Once I have been successful in creating a model that is ready to be animated in each of the two software, I will reflect on my experiences with both pieces of software, and discuss the differences between them.
Max vs. Maya
To start the practical aspects of this project, I intend to take the research I have completed and put it into practice. First I am going to rig and skin a model I have generated using Autodesk’s Character Generator in 3DSMax, detailing my process as I go, as well as weighing the pro’s and con’s of the software, and summarising what I have learned whilst using it.
I will then move to Maya, and using the same model, I will rig and skin it in that software, following the same procedure as above for detailing my experiences.
Once I have been successful in creating a model that is ready to be animated in each of the two software, I will reflect on my experiences with both pieces of software, and discuss the differences between them.
Autodesk 3DSMax
Rigging
Rigging
In regards to learning how to rig and skin in 3DSMax I thought it would be most beneficial to speak to my tutor Lee, since he has a wealth of knowledge in this particular piece of software. He agreed to hold a workshop on the subject, and this is where I gained the majority of my knowledge for this practical.
I learned that before starting, it is heavily beneficial to have your model in a symmetrical pose, it is not a requirement, but it will speed up the workflow, as for why will be stated later.
The actual rigging in 3DSMax is done using a tool called a “CAT Parent”, it is created like all objects by clicking and dragging in the view pane. The most important part lies here, in the scale of the parent. The idea is to create this controller at the base of your models feet, once you have it, you can hit ‘create pelvis’ in the toolbox, this will place a cuboid above the parent, which will act as the root and pelvis of your rig. However, its important here to get it positioned right, as I’ve found out the hard way, and the main problem is that it’s down to trial and error. You can’t just simply move the pelvis around once its created, I’m not sure exactly why this is the case. So when creating your pelvis, make sure it ends up amongst the hips of your model, if not, you need to delete the entire thing and go again, if its ending up too high, try creating the parent a little smaller, and vice versa. The reason you need to get it right where you need it, is that, if its off, it tends to throw out the IK’s in your leg controllers, causing them to bend over/under, and simply moving the pelvis won’t help.
Once you have this down, you can create the leg by using the add limbs button. There is one for the leg, and another for the arm for later.
The actual rigging in 3DSMax is done using a tool called a “CAT Parent”, it is created like all objects by clicking and dragging in the view pane. The most important part lies here, in the scale of the parent. The idea is to create this controller at the base of your models feet, once you have it, you can hit ‘create pelvis’ in the toolbox, this will place a cuboid above the parent, which will act as the root and pelvis of your rig. However, its important here to get it positioned right, as I’ve found out the hard way, and the main problem is that it’s down to trial and error. You can’t just simply move the pelvis around once its created, I’m not sure exactly why this is the case. So when creating your pelvis, make sure it ends up amongst the hips of your model, if not, you need to delete the entire thing and go again, if its ending up too high, try creating the parent a little smaller, and vice versa. The reason you need to get it right where you need it, is that, if its off, it tends to throw out the IK’s in your leg controllers, causing them to bend over/under, and simply moving the pelvis won’t help.
Once you have this down, you can create the leg by using the add limbs button. There is one for the leg, and another for the arm for later.
Once you’ve created the leg, you have to be sure to move the controller into position first, as this is the IK and controls the entire leg, then you can go about bringing the heel to the floor and lining up the knee joint with your mesh. Once the rig is positioned where you want it and everything is looking flush, you can simply hit the ‘add leg’ button again and it will create another on the other side, but it does so by mirroring your first leg. This is why it is a good idea to have a model in a symmetrical pose, as you only have to deal with half of the limbs.
The next step is to create your spine… I like to add three spine segments above the pelvis, the top most one will act as the shoulders, whereas the two beneath will allow for a reasonable amount of curvature in the back, any more than this would just be overkill I think.
The next step is to create your spine… I like to add three spine segments above the pelvis, the top most one will act as the shoulders, whereas the two beneath will allow for a reasonable amount of curvature in the back, any more than this would just be overkill I think.
The arm is positioned in much the same way as the leg, however, the noteworthy aspect here is the orientation of the hand, since it’s just a block, it isn’t quite possible to know which way up it is. In order to deal with this, click it and add the 5 appendices that make up the fingers, this will include a thumb, which will give away what way around it needs to be to fit your model. When adding fingers, you if you go about them one at a time, as in, type in a value of 1 in the digits to start, then rescale and move the bones so the joints meet those in your mesh, you can change the value to 2, and it will add another finger bone with the same values as the first one you edited, saving you a bit of time. Obviously each of the 5 fingers are different, so a change to each will still need to be made, however it will be better than rescaling them all from the default position.
Once you have your hand rigged and looking good, again, as long as your model is in a symmetrical pose, you can hit add arm again, and it will replicate everything over to the other side, mirroring the values, saving you from having to endure those pesky finger bones again.
Once you have your hand rigged and looking good, again, as long as your model is in a symmetrical pose, you can hit add arm again, and it will replicate everything over to the other side, mirroring the values, saving you from having to endure those pesky finger bones again.
The last step to finalise your rig is to add the head bone. My first thought was, well where’s the button for “add head”, and the fact is, there isn’t one, the head bone is an extension of the spine, so you just have to simply select the top of the spine, or the shoulders in this case, and add two more segments, I like to rescale the top most bone to the size of the head, and slim the bottom one down to the size of the neck, this is mostly aesthetic, but helps when animating. The last step is to make sure the rig is lined up nice, and then you’re ready to move onto skinning.
A note worth making here is that with the head bone, in the same way we added the toe bone to the foot, we can add more bones that in turn could be linked to facial features such as the jaw, and eyes, etc. I haven’t added any to my rig, as this is just to show motion for games, but I do have an understanding of how it works.
A note worth making here is that with the head bone, in the same way we added the toe bone to the foot, we can add more bones that in turn could be linked to facial features such as the jaw, and eyes, etc. I haven’t added any to my rig, as this is just to show motion for games, but I do have an understanding of how it works.
Skinning
Working the skin for your model in 3DSMax is actually a little simpler than I had first imagined it to be, before starting out I heard a lot of horror stories about how much of a pain the skinning process was, but this wasn’t the case for me.
Once the rig was set up how I wanted, it was a simple task of selecting the mesh, going into the modifier panel and selecting skin.
It’s not necessary, but an important tip here is to create an animation layer on the rig, with a simple pose change, such as the arm bending and the leg lifting off the ground. This way, when you’re working on the skinning process, you can simply scrub the timeline to see the quality of the skin without repositioning your rig.
The next step is to add the bones to the skin, so the modifier knows what it is working with. There’s a tab with a plus checkbox that brings up the object list in the scene, what you want to do here is select all the bones in the pelvis hierarchy. Be sure to only select the bones, and ignore the feet IK controllers and anything else that might be set up, it may not cause problems right away, but it will somewhere down the line. An example is that when importing a rig into unreal, the game engine can only recognize a rig with one root, since the IK handles aren’t actually parented to the pelvis, like the bones are, it will cause a failed import.
Once the bones are added to the modifier, I started altering the skin by hitting the weight solver, using the voxel distributor over the heat map, this practically adjusted my skin perfectly. The only issue I had was that the lower chin was somehow connected to the chest, causing it to drag and stretch when rotating the head bone. To solve this, I opened the weight tool, which is found just below the weight solver, and selected all the vertices in the chin that were being affected, and put a weight of 1 to the head bone. This meant that the head bone had full control over the movement of the selected area.
After touching up some vertices with a .75 weight between the neck bone and head, the skin was at a reasonable state.
I now have a rigged and skinned mesh ready to be animated.
Once the rig was set up how I wanted, it was a simple task of selecting the mesh, going into the modifier panel and selecting skin.
It’s not necessary, but an important tip here is to create an animation layer on the rig, with a simple pose change, such as the arm bending and the leg lifting off the ground. This way, when you’re working on the skinning process, you can simply scrub the timeline to see the quality of the skin without repositioning your rig.
The next step is to add the bones to the skin, so the modifier knows what it is working with. There’s a tab with a plus checkbox that brings up the object list in the scene, what you want to do here is select all the bones in the pelvis hierarchy. Be sure to only select the bones, and ignore the feet IK controllers and anything else that might be set up, it may not cause problems right away, but it will somewhere down the line. An example is that when importing a rig into unreal, the game engine can only recognize a rig with one root, since the IK handles aren’t actually parented to the pelvis, like the bones are, it will cause a failed import.
Once the bones are added to the modifier, I started altering the skin by hitting the weight solver, using the voxel distributor over the heat map, this practically adjusted my skin perfectly. The only issue I had was that the lower chin was somehow connected to the chest, causing it to drag and stretch when rotating the head bone. To solve this, I opened the weight tool, which is found just below the weight solver, and selected all the vertices in the chin that were being affected, and put a weight of 1 to the head bone. This meant that the head bone had full control over the movement of the selected area.
After touching up some vertices with a .75 weight between the neck bone and head, the skin was at a reasonable state.
I now have a rigged and skinned mesh ready to be animated.
(Video Below):
Autodesk Maya
Rigging
Rigging
Rigging in Maya was a real challenge for me, mostly because I haven’t had the opportunity to use this software since 2012. The first obstacle to overcome was navigating the scene and UI. Once I had figured at least that much out, I looked for help in learning to rig in Maya from a variety of sources. I had found a tutorial on YouTube by Jamie Telford entitled “Basic Bipedal Character Rigging Setup in Maya”. This tutorial was a breath of fresh air compared to the others that are out there, he talks simply enough for you to understand without prior knowledge, but not so simply as to waste time making you feel incompetent. He also takes the time to explain why we are doing things as we are going along, so you know why you’re doing something, and not just what. I strongly believe that this kind of teaching helps the knowledge to stick better, so you’ll spend less time learning, and more time doing.
Telford explains to us about the ease of rigging if your model is set up in a symmetrical pose, just like in 3DSMax, Maya has some mirroring options for the bones to speed up the process. He explains where each bone should go, and gives his reasons for doing so. Rigging in Maya for the most part is simply clicking and positioning a chain of bones. Using the orthographic views here help greatly with getting your positioning just right. It is also good practice to get into the habit of naming your bones as you go, this will speed things up later.
Once you have all your bones in place, you can select the skeleton and the mesh and hit the “Smooth Bind Skin” tool, this will apply an automatic skin, which we can clean up a little later. It’s then time to set up some controllers and IK Splines.
Once you have all your bones in place, you can select the skeleton and the mesh and hit the “Smooth Bind Skin” tool, this will apply an automatic skin, which we can clean up a little later. It’s then time to set up some controllers and IK Splines.
The IK splines are a lot simpler to set up than I had expected, you just hit the IK spline tool, and go from root to end, so for the legs, it will start with the hip bone, and end with the ankle, for the arms, it will start with the shoulder bone, and end in the wrist.
Creating a controller initially is as simple as creating a curve, and bringing it in line with the bone you want it attached to, you can shape the curve however you want, its simply aesthetic, but the main point is that it is outside the geometry and can be easily selected. To make things a little smoother when animating, you can lock and hide the scale transformations to prevent them from being set a key when you animate later down the line, once you have done this, you can then freeze transformations which will reset the units all to 0, meaning the pose your model is in now will be its default animation pose that you can easily get back to. Lastly, in order to attach the controller to the bone, you just need to select both the curve and the IK handle, and hit point constraint, and then orient constraint. This will then allow you to move and rotate the bone and the spline, by selecting its controller. It is wise to add controllers to all the major bones that you will be animating, these would be the feet, the hands, the pelvis, the spine and the head and shoulders.
Once you have all the controls set up, it is finally just a case of cleaning up the skin we automated on to the mesh, and we should be ready to animate.
Once you have all the controls set up, it is finally just a case of cleaning up the skin we automated on to the mesh, and we should be ready to animate.
Autodesk Maya
Skinning
Skinning
I was going to write up a separate section on the skinning process in Maya, much like I did for Max, however I mentioned the “Smooth Bind Skin” button that I used in the rigging process, just simply having the bone structure and the mesh selected, and having then clicked this button seems to have skinned my rig perfectly. Below I’ll drop a few examples of stretching the skin so you can see for yourself just how well it managed to be completed by just the click of a button.
(Video Below):
(Video Below):
What I have learnt:
• Rigging a Mesh in 3DSMax with CatRig
• Skinning a Mesh to a CatRig using Voxel Heatmapping and Weight Blending
• Skinning a Mesh to a CatRig using Voxel Heatmapping and Weight Blending
• Rigging a Mesh using Bones in Maya
• Applying IK Splines to Bones to Create IK Targets
• Setting up Controllers to Bones with Constraints
• Skinning a Mesh to Bones using the Smooth Bind Tool
• Applying IK Splines to Bones to Create IK Targets
• Setting up Controllers to Bones with Constraints
• Skinning a Mesh to Bones using the Smooth Bind Tool
