Today we learnt about setting up a basic facial rig by using shape keys and drivers.
Shape Keys
The first thing was to sort out getting a model, for this we used Suzanne, and applied one Subdivision modifier and added another to get vertices and smooth it out.
Then we were taken through how to create shape keys. Shape keys are basically a recording of the vertices on a model, my moving them about and having them on a Shape Key Blender interpolates the movement of these and thus you can animate and move them.
We made shape keys for closing the mouth, left and right eyebrow movements (one for up and one for down), left and right smile movements and even a blink (mine didn’t come out too great but I can learn from it for future). You can see below some fun I had with adjusting the influence of these.
We also learnt how to use vertex groups to separate out elements of the model by weight painting (so you can make a shape key for both brow movements, and copy this with new shape from mix, and assign the corresponding left/right vertex group).
Drivers
When it comes to controlling these values we need to connect them, and the way we do that is by creating a driver. A driver is a mathematical connection between the value and what you choose to control it (via a variable).
The way to do this is to create controllers (we used armatures in this case changed to empties as we learnt in previous weeks). We set our limit transform and lock our unused axis so that we just have this up and down movement. Then we go into our shape key and add a driver to the value, selecting our armature and controller in the variable menu. Then comes the math which had me very confused at first but I sort of got the hang out it later on, so once we have set these up- we need to make sure that our variable expression adds up to 1 (since that will turn our shape key on) and that is done with math. Then once that is sorted the control should work! I learnt that AFTER I had set my rig up that you should overshoot your Shape Keys, so that you have a lot more room for movement and flexibility when animating, so I know that now for future rigs.
Then I just quickly through together this animations before the end of class, the timing is off but it shows what the model could move like, with a better rig and more time this would have been a lot smoother.
Then once I was home I learnt a bit more about rigs.
I started by following Mike’s tutorial on connecting a Shape Key to a rotation on the bone. This was done in a similar way as above, just set up the armature and auto weight parent it. Then set up a Shape Key as a bicep, add a driver to this and and set the transform to the rotation of the top bone. Then you make sure to change the X Location to whatever axis Rotation, and do some maths to help. To finish this off I added a limit rotation on the arm as well.
Then I wanted to learn about the Progressive Shape keys, since the blink on my monkey didn’t go too well. Again I followed along with Mike’s tutorial and set up some similar shapes, using a cylinder that I inset the faces on and bridge edge looped inside. Then I went and duplicated these and scaled so I had this sort of telescoping shape.
I went and set up Shape keys for each of the stages, moving the parts above and scaling to fill the space, duplicating the model and adjusting on it to join shape and then I had all my stages set up. I then went and set these to follow the stage previous when possible so that it relatively scaled.
Then I went and created a custom property to scale these on. I copied the data path of this value and added drivers to each of my shape keys using the property as my variable. The way this works for progressive objects, is to times the variable by the amount of stages, so here I have 3 shape keys and so my initial expression is var*3, meaning that when my value hits around 3.3 my first stage will have a value of 1, then for each proceeding stage I will -1 ( so (var*3)-1 ) and so on, giving me the final result of one controller for all of these stages.
Extra Work
I decided to have a redo of my monkey rig and this time it went a lot better, using weight painting I added some bones to make the Jaw and ear move as well as giving the blink another go. While it didn’t turn out amazing I think it was a bit better with the set up and I also included a Damped Track (for this I used the eyeballs that came with Suzanne but these didn’t work at all and kept clipping). So, I played around and added some slight animation here as well to check that it worked.
I also wanted to have a go at recreating this floaty sphere cube transition that Mike made and showed us, using what knowledge he gave us at the start of class and a bit of searching online. So the first thing I did was to set up a sphere, and then create a cube and duplicating my sphere, I scaled this up to cover the whole box and then applied a shrink wrap modifier so that it become the shape of the cube and applying this. I then added this as a Shape Key to my original Sphere and deleted this. Then to get the wavey movement I added a wave modifier and a solidify modifier and went to play with the material. For this I had a set up with a Fresnel and emission node that hooked into a Mix Shader, adjusting the colours and values to fit. I then duplicated these and scaled downwards so I had multiple of these wavy shapes and made sure to adjust the Alpha on them so they were see through.
I then keyframed the shape key and rendered this out. I thought the first pass was too strong so I went ahead and did a second render with a decreased emisson and adjusting the Bloom output, as well as playign in the compositor menu to add a bit of glare. WHile it doesn’y look like Mike’s version I still think it looks pretty cool and I learnt about some new nodes!