I thought the cheetah looked too smooth, so I tried to add some kind of muscle definition. It’s hard to see exactly what the muscles look like for the reference images i have though.
I have been working on and off on the cheetah model for my major project since before christmas, so I thought it was about time I posted it here 
There is however something with it that I’m not quite happy about, especially with the head, but I can’t put my finger on it. Well I have to finish it off soon, so there will hopefully be an update within the next week.
For my Innovations Project I did a painterly motion blur for moving images.
I got inspired to do this from images by the artist Bill Hall.
I started by looking into ways of manipulating motion vectors, rendered from a short clip of animation. I tested different masks made from both moving and still images, such as smoke and elephant skin. The idea was to mask out areas that wouldn’t be affected by the motion blur and therefore get an interesting pattern for where the detail would appear. I also tested different inputs to change the shape of the motion vectors. On its own this turned out to give a too random result.
Later tests were done with displacements. I started out by doing tests on still images by experimenting with distortion filters in Photoshop. By following an article in Computer Arts Magazine by Pete Harrison, Photoshop Displacement Effects, I produced the following images.
Original image displaced with a black and white image. (Black and white image from Pete Harrison.)
Original image layered with the displaced image where parts have been erased.
I later tried to get the same results for moving images by using moving images as input for the displacement, in Shake instead of Photoshop. I tested a number of different pieces of footage as displacement, both 3D and video. The conclusion was that high contrasted footage, such as coloured liquid on dark backgrounds, gave more of a trailing effect than smoother images, such as smoke. I also noticed how much easier it is to create something that looks nice for a still image rather than moving ones.
A test where two pieces of footage of different kinds of liquid (filmed) were used as displacement in two layers. (The middle image is from footage shot by students on the MA Digital Effects Course.)
Mixing and layering different tests lead to the latest image sequence.
In the following 5 steps, Maya and Shake have been used, though other 3D and post production software with similar functions can be used.
Step 1 – Animated sequence
To create this kind of motion blur, an animated sequence with a subject moving relative to the camera is needed. The images generated from this sequence should not have any kind of blur due to motion (other kinds of blur, such as depth of field, are acceptable). This is the base pass.
Step 2 – Exaggerated “natural?? motion blur
This step can be done in one of two ways. The second pass can be rendered out with motion vectors (using Reel Smart Motion Blur). Motion vectors allow you to interactively change the amount of motion blur in post production software (assuming you have the Reel Smart Motion Blur plugin). This makes it easier to see how much “natural?? motion blur is needed to fit with the later passes, without having to render out more than the base pass (image below).Exaggerating it slightly will give a more dramatic effect and will enable this pass to fit better with the subsequent stages of this process. Alternatively the animated sequence can be rendered out with “natural?? motion blur already added. However, bear in mind that if this pass does not fit with later passes it will have to be rendered out again with different motion blur settings.
Base pass combined with motion vector pass giving, with the right settings, the exaggerated “natural?? motion blur pass.
Step 3 – Displacement with irregular background
The next pass is generated using an IDisplace node. The IDisplace node has two inputs. The first is the image to be displaced and the second is the source of the displacement. The IDisplace node distorts the images of the first input in x and y according to the colour channels specified of the source of the displacement, the second input. Using different colour channels for the distortion in x and in y can create a slightly asymmetric distortion.
The first input used for this pass is the base pass. The second is a filmed grainy irregular background, where the red channel is specified to distort in x and the green channel in y (image below). This creates a slightly irregular distortion of the base pass that works well as a merger of the passes produced in previous and following step.
Base pass displaced with a grainy image as source.
Step 4 – Displacement with filmed liquid
This step also uses the IDisplace node. First create three instances of the base pass fileIn node, A, B and C. Leave A unchanged, but reposition nodes B and C by -1 and -2 frames respectively. Nodes B and C now appear behind A as a trail when the sequence is played back. The fileIn nodes are then plugged in to the first input of three separate IDisplace nodes.
The source of displacement is footage of a liquid running down a pane of glass. Depending on the quality of the footage, this fileIn node may need to have its contrast increased.
The filmed footage should be rotated and skewed to fit the direction and the perspective of the object in motion (image below). The output is then plugged into all three secondary inputs of the three IDisplace nodes and again the red channel is set to distort in x and the green in y.
Base pass displaced with filmed footage of liquid. Here the three displaced images are layered, with different opacities, into one.
Step 5 – Mixing and layering the different passes together
Now the different passes can be added together. First mix the exaggerated “natural?? motion blur pass of step 2, with the displacement pass of step 3 and leave the opacity at 50% to show the two passes equally. To achieve a blurry effect on top of this, layer the output of the mix layer with the “natural?? motion blur again in a max layer.
Combine B and C with a second mix layer, B as input one and C as input two. Use this output in a third mix layer together with A. Adjust the opacity of these two mix layers so that A is more visible than B and B more than C, to give an effect of the displacement fading away when played back.
To complete the last step of creating the painterly motion blur, combine the output of the max layer and the output of the third mix layer in a new max layer.
After finishing the woman’s rig I started rigging the second character, the cheetah. Since I had never rigged a four legged animal before, I had a look around earlier in this project for examples of how other people have rigged quadrupeds. I found one free rig of a puma by Kiel Figgins (Rig Set 5), that I used in my block test. I first thought I could use this one even in my final piece, but fitting it to my character. However, from using the rig in my block test I had found a couple of things that I wanted to change. When I started changing these, though changing these made me find more things that I wanted to have in a different way. I therefore ended up making my own rig, but following Kiel Figgins’ puma as an example.
The Skeleton – In opposite to the human rig, where the root is close to our pelvis, with spine joints working up towards the head, the root joint of the cheetah is between its shoulder blades, with four spine joints going down towards the tail. The fourth of these spine joints is treated as a second root, to allow for the front and the back of the cheetah to move independently. From the back root the back legs follow with a similar setup to a human leg, with hip, knee, heel/ankle, ball and toe. The difference is that a cat’s ball is much more flexible than the ball of a human foot, which allows the cat to walk comfortably in away that would be equivalent to us walking around on our toes. The heel/ankle of the back leg is therefore placed much higher than on a human leg.
The tail follows after the back root, similar to an elongated spine.
In the same way the back legs has a lot in common with human legs, the front legs are similar to human arms, with shoulder blade/clavicle, shoulder, elbow and wrist. After the wrist cats have paws instead of hands.
The Back Legs – To get the movement of a cat’s leg I have used three IK chains on each back leg. One from the hip to the heel, with much the same function as the hip to ankle IK would have on a human rig. From the heel there is a single chain IK to the ball and one from the ball to the toe. Parenting the first IK handle to the ankle control and the second and the third to the paw control makes you able to split the movement so the heel and paw can be moved independently. Since the heel of the cheetah works in a similar way to a human’s heel, it should only be able to rotate in one axis. Therefore to not “break” the heel when the ankle control is moved from side to side, the movement of the paw control is driven by an expression that always keeps the paw in line with the ankle.
The Front Legs – The clavicle of the cheetah is placed close to the front root, to get motion of a shoulder blade. These are then controlled by FK Shoulder Controls.
Similar to the back leg setup, the front legs are also set up with three IK chains parented under two controls with the same expressions.
The Body – The spine is split up in two independent roots by using two IK chains. The first is a spline IK starting from the front root and ending on the third joint down the spine. From this joint another IK starts, a single chain IK, ending on the back root. This gives you a lot of control over the curvature of the back and you can also move the back part of the body independently from the front.
The Tail – This part of the cheetah is controlled by a spline IK with control clusters assigned to the control vertices of the curve of the IK. I tried at first to just use FK controls for the tail, but decided against it since it requires a lot more controls for the same round movement as with a spline IK.
The Head and Neck – I wanted to be able to have isolated head movements, the head and neck are therefore setup in much the same way I set up the head and neck of the woman, following Jason Schleifer’s tutorial. To get complete control over the ears they were set up with FK control curves. The eyes were also setup in a similar way to the woman’s, with aim constraints to get isolated motions.
Gave the woman some clothes and hair a while ago, but never posted them. So here is a small update on the female model.
I plan to use wire deformers for the dress with hair dynamics and I probably have to look over the positioning of the eye brows again. I know the hair line isn’t too pretty atm either, but I will see how much I can get away with in terms of texturing before I change anything.
Finally I have got the first draft of the whole block test done. It took a lot of pushing and forcing myself and even some pushing from Dan. I really don’t like doing block tests, but it is a “have to” to see what works and what doesn’t. So it’s just a matter of self discipline in the end I guess. Just too bad that I am in distinct lack of anything of the sort.
Anyway…here it is.
I’m not quite there yet though. As I have said before, I want the three loops to have different meanings. Where the first is supposed to be a clear chase, the second is there to confuse the viewer to what actually is happening. Then the third is supposed to make it all clear again. At the moment I think the first loop is working. It’s clear what is going on and it corresponds with what the viewer think is logical or plausible. The second loop on the other hand is not working as it is. I think there is more than one reason for this:
You as a viewer can only hold the information of very few shots in your head at one time. Therefore, in this case, when a loop ends what stays in your mind/your impression of the loop will mainly be based on the about 6 last shots of the loop. The subtle changes in the second loop, compared to the first, happen in the first half of the loop. Therefore when there is a slight pause, before the next loop starts, the shots the viewer holds in its head are the same as the ones for the first loop. The viewer might have a slight feeling that there were some differences, but won’t be able to tell what they were unless he/she watches the animation again.
To prevent these changes in the loop could be put more towards the end to make the ending of the loop different compared to the first. Another way to prevent this could be to have the excising changes more drastic to clearly show a change from one loop to the next.
To be able to notice a subtle change in something you need time. Therefore to convey something through subtle differences suits still images better than moving images. This is simply because than the viewer gets more time to notice and understand the change. With moving images you therefore need to either be more obvious or to give the viewer more time. This could e.g. be done through a constellation that loops, where the viewer can stay and watch for as long as they want.
The solution to this could either be to simply make the message, which I want to convey with each loop, more obvious. Something to watch out for doing this is to avoid making it too obvious. I still want the viewer to walk away from watching the animation feeling a bit clever for understanding. In the same time the worst case scenario would obviously be the exact opposite. The context which something occurs in can change if it appears obvious or not though. For example when the viewer watch the second loop I assume that he/she has seen the first and therefore has an idea of what they think is happening. To make him/her change their mind it will therefore take more than if the second loop would have been watched on its own and therefore had its contents evaluated separately.
The third loop is not clear enough as it is at the moment, but it’s getting there. I have tried to link motions from the woman and the cheetah together through similar framing and motions and then cutting them together to one. This needs to be more obvious than it is at the moment. I will try to do this by matching the movements better and see if I can use dissolves instead of cuts at some points. As the third loop is at the moment it could possibly work as the second loop instead and then make another version of this loop that is clearer to use as the third.
For my animation I need a model of an African woman and a cheetah. I started with the Woman and used reference images from 3d.sk.
I am not really sure how I will give her eye brows and eye lashes yet. At some point I will have to give her some hair as well. I am planning on keeping it to a short afro.
She also needs some clothes. I think I will make something being wrapped and tied around her.
In a tutorial with Phil Spicer he advised me to make flip books out of my story board images to try it out before I made it into a block test. This was to see quickly if the sequence would work, but without making an animatic. It also meant that I could jumble the images up as a deck of cards and create a large number of different loops. I could then see how the different orders of the images could make the sequence get a different meaning, instead of going the other way and trying to arrange the images in a way so they would mean different things. The idea was then also that I would be able to see how many different loops that actually could be made from the same images. It did however not turn out to work this way. Because there were so few images it was hard to flick through them without missing out a few or more. I tried different sizes of the images, different kinds of paper and I also tried to use double copies of every image to make it easier to flick through. It still didn’t give a satisfying result and instead it left me with frustration and confusion when I tried to make out what the new sequence meant. This could however turn to my advantage and help me with my second loop in my animation where I will try to make the viewer confused and maybe even frustrated over what is going on. To recreate this feeling that I got from the flip books, a loop could either contain deliberate errors or maybe even break.
When I started with the block test the idea was that all the shots would be the same length to create a steady rhythm that would feel like a heartbeat all the way through the animation. The tension would then build up through having shorter and shorter loops.
After creating the first version of my bock test I noticed that this didn’t really work. It was too slow and felt monotonous and dull. I also realised that it might not be necessary to have the woman and the cheetah doing the same motions and therefore have them in similar shots. Instead I thought that I could try to make them opposites of each other. As the animation progressed I could then have the woman go from 0-1 and the cheetah from 1-0 and later on letting them meet in the middle.
Later I happened to watch the trailer from Apocalypto (directed by Mel Gibson) that really inspired me to change my block test. I liked the music and the speedy rhythm of it and thought if I could find some similar music maybe that would help me find the right rhythm to make the animation feel more like a chase. I ended up cutting together some of the music from that same trailer and then using it for the second version of my block test.
It still needs some work, but I am happy with it for now and will now go onto sorting out the other loops.
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