Much Needed Update

I've been really busy in the past few weeks with dissertation work and other projects, hence, the blogging has taken a back seat of late. Anyhow, things have come a long way. I've nearly done all the working parts of the rig (skeleton, skin weighting, muscles, etc.) and I'll soon be moving on to constraining control curves to everything and finishing it off. After that it's the home straight with just some animation cycles to do to demonstrate that the rig works properly and that, most importantly, I'll be able to animate with it when it comes to making the film next year.

The initial skin weighting was (as always) soul-crushingly tedious and a massive pain in the ass but I managed to get the best movement I could before converting the skin cluster to a muscle system. Here's the rig at the stage after weight painting was finished:

Notice in the video that the basic skin cluster system has some deformation problems around the legs. This is something that can't really be fixed using normal skin weights since adding influence to make the leg fuller when stretched forward would cause it to cave in more when stretched backwards, and vice versa.

At the stage when the skin cluster was weighted as well as possible I then moved on the muscle system. I only really needed to do muscles for the legs mainly since that's where most of the remaining deformation problems were. I put some in the neck too to keep it from collapsing when it was bent to the side.

Here's a demo of it with the muscle system:

The muscle system ironed out some of the problems with the deformations fairly well, but the iconic scapular movement of the tiger still isn't there. What I had planned to do here was to model a scapular bone from polygons, convert it to a muscle object and then paint sliding weights as well as some sticky weights and have it move under the skin.

This did work, but for some reason it gave the rig unworkable slow-down even if I turned the sliding weight evaluation off in the cmusclesystem1 node. The way I eventually got round this was by using normal capsule bones instead which are faster to solve than polygon shapes.

I then went about creating and IK/FK switch system. I originally wasn't going to include this, but I decided to do it in the end since I don't know exactly what sort of movement I might want to animate for the film next year. I did this the traditional way, duplicating the joints I wanted included in the IK/FK system then orient contraining the original joints both to the new IK chain and FK chain. I then created a curve control which was parented to the foot to be used as the switch. On this control I added the 'IKFKSwitch' attribute with limits of 0 to 10.

The control's new attribute was to blend between the IK chain's constraint and the FK chain's constraint as the value was changed between 0 and 10. The way I got that working was to set the IK/FK control as the driver and the IK and FK constraints as the driven with the 'set driven key' tool, so the IK chain has full influence over the original chain at 0 and the FK chain has full influence at 10.

After that was the long, tedious process of creating control curves and constraints for everything else. For the FK areas I used the 'null group method'. This involves creating the curve and making it a child of a null group, orient constraining the curve to the joint you want rotational control over and then parent constraining the null group to the joint above in the heirarchy. The reason the curve is made a child of a null group is the if it was parent constrained directly to the joint above, it wouldn't allow animation to be added since any movement of the joints above would cause it to snap back its origin.

Other constraint types used a similar process as the FK controls but with different constraints. Many of the facial controls are curves with the relevant joints constrained to them using aim constraints or driven keys.

For the tail I used IK spline handles with control curves having influence over groups of spline curve clusters. The tongue, for example, uses spline clusters point-constrained to curve controls while the tail uses spline clusters orient-constrained to control curves which give control similar to FK, but slightly smoother.

The rig is near-enough finished now, so here's a video showing it in use:

There are still a couple of glitches to iron out, and I'll be working on those next.

Starting the Rig

Having fine-tuned the model the tiger is now ready for rigging. I've decided to used a mesh which is double the resolution of the base mesh I initially modelled in order to give a higher level of control over the deformations.

I've spent a long time poring over videos on the internet of tigers moving in various ways. One of the biggest challenges, it seems, is getting the tiger's unique front leg and clavicle movement right. What I've found from the videos is that the clavicle is always more or less pointing towards the paw. This is an effect I thought could be achieved by somehow utilising an aim constraint which dictated the rotation of the clavicle as pointing toward the paw.

I decided to test this out and came up with this:

I think with a little fiddling about and maybe adding a physical clavicle bone mesh into the muscle system it'll work pretty well.

Having done that I've made most of the rest of the skeleton:

Now I'm moving on to the facial rigging which I think is going to be a big challenge to get right. I think I'll probably do the whole face using joints as these give a more organic, non-linear feel than blend shapes.

More soon.

It's Been a While

I haven't updated in a good 2 weeks so I thought it would be a good idea to do so while I remember to. The lack of updates doesn't mean I've not been doing anything: quite the opposite! I've been basically working non-stop on all my projects and just haven't found the right chances to update anything.

The main thing in the past 2 weeks has been modelling the tiger. It's taken a fair bit longer than on other models purely because I was it to be at a high enough standard to sit in along side live-action footage. This means I need to get the everything spot on and to do that I've been scouring the internet for as much reference material as I can find to get it right.

Having found enough reference material to begin, I started drawing out a concept image and the front and side profiles to start modelling from:

At the moment the base model is complete, including the inside of the mouth (teeth, tongue, jaw, etc.) and I've taken it into Mudbox to sculpt the muscles in and tweak and correct certain details.

Here are the base models for the tiger, its jaw, teeth and tongue:

Having finished this stage I cut out UVs for the model in Roadkill:

The next stage is doing the finer details in Mudbox, which is where I'm at now. Here's the state of the model thus far:

I've trying to think of a way of getting a good-looking furry effect without relying too much on Maya fur at render time. So far I've used a stencil in Mudbox to sculpt a furry effect onto the model. It works alright but I did it very quickly and won't be settling for it the way it looks now.

That's everything. I'll probably start rigging it very soon as the texturing can wait until last really.

Clarity

I have been asked by my tutors exactly what I expect to have for this project by the deadline. Obviously, concepting, modelling, texturing, and rigging a realistic tiger along with all the muscle systems, weights and bones and then animating it in a match-moved film with dynamic fur, realistic lighting and a ton of post-production is probably a little too much to expect from one person in one semester especially considering all the other projects I have on the go. All along I intended for this film to be my main project for the whole year but perhaps I haven't made that completely clear and, thus, look like a crazy masochist with a wish for suicide by exhaustion.

Let me dispel that idea and reassure anyone reading this that I'm not completely mental and will only be doing half-ish of that colossal pile of work. By the end of this semester, I aim to have an intuitive and detailed rig of a realistic, anatomically correct tiger along with some realistic animations; run cycles, walk cycles, etc. Of course, this might look a lot like character rigging, but the difference is that this rig is to be used to try and suspend disbelief alongside live-action footage and as such will be much more of a challenge than rigging and animating something which has come entirely from my imagination.

Hopefully this makes this a little clearer.

Before I go, I've been amassing an impressively huge collection of reference images and videos of tigers and have started modelling the beast itself.

More on all that soon.

The Idea is Falling into Place

After much thought I've come up with a final idea for the film. The idea centres around the idea of adopting a big cat. We often see adverts about adopting wild animals for their welfare, although the animal is in another part of the world, the premise is that for a monthly contribution, the person adopting the animal receives regular updates on how it's doing and maybe gets a card and a soft toy. I'm going to put a twist on that.

My film will be about someone who goes on to the internet and signs up to adopt a big cat (a tiger, jaguar or leopard, preferably one without too much thick fur since I'm not concentrating on my ability to create ridiculous render times). A few days after signing up they get a knock at the door and open it to a delivery man asking for a signature for a package. Expecting it to be the card and plush toy the person signs for it without really thinking too much about it.

Then they notice a large, (probably match-moved) wooden crate outside as the van drives away. Once opened, he finds that he's actually ended up having a real, live big cat shipped over and delivered to his door. It's not aggressive which is good news. The film then shows life with the big cat; house training it, taking it to the park and the funny situations which could accompany these things. Our proud new owner of the big cat becomes more and more attached to the animal throughout the short montage until tragedy hits. His payment is declined and the animal is taken away.

Here's the rough script so far. There won't be any dialogue through the film beyond maybe a "cheers" from the  delivery man as he gets his signature:

> [Desaturated, limited colour palette] Close-up of a computer screen, cursor moving over 'Adopt a Big Cat' website. Fade to Black.
> Sudden shot of a young man (early twenties a student) sitting up from bed followed by a series of quick cuts showing breakfast being made (Edgar Wright-style) due to desaturated colours, everything seams dull and routine: KETTLE ON / TOASTER ON / POUR TEA / TOAST POP / EGGS FRYING / CLOSE-UP OF GUY'S MOUTH AS HE BITES AND CHEWS TOAST, CHEWING STOPS AS A KNOCK IS HEARD FROM THE FRONT DOOR.
> Quick cutting ends giving way to a continuous shot of him walking through the hallway to the front door. Shot continues as the door is opened to a postman. Camera settles over the student's shoulder as the postman says "Signature?" and the package is signed for. "Cheers" says postman as he walks off. Camera angle changes to the other shoulder revealing a large wooden crate (match-moved).
> Enter the big cat.
> [Colours become increasingly bright, lively and more saturated, almost dream-like through the next few shots] Initial fear gives way to a montage of life with the animal: shots of the it in the house, house training, playing fetch in the park, all the while showing a growing fondness between man and animal. Probably have some sort  of music here.
> Montage fades out (always fade out in a montage!).
> Another breakfast scene again, very similar to the first one but with a sense of happiness (saturated colours, smiling while eating toast).
> Shot of computer screen again "Payment declined - Insufficient funds"
> Close-up of student's eyes: surprised and upset. [Colours return to desaturated as realisation kicks in]
> Knock at the door.
> The animal is taken away and the shot fades to black.

I might add a third breakfast scene showing a return to boring normal life but this might be overkill.

Anyway, that's it so far. I'm now in the process of story boarding the shots.

Why's the Hell is There a Tiger in Cambridge?

This is a bit of a problem, assuming I'm to create a film about a sabre tooth cat in Cambridge. If there's no reason for this animal to be there, the film could fall apart whether it is technically impressive or not. Even though the narrative and film work aren't a priority and aren't something I'll be being marked on, I want to aim for something which is cohesive and which makes sense so that I end up with a piece of work I'm happy with (that's if I get as far as doing a film).

I'll obviously be thinking of ways I can resolve this problem or even just changing it entirely into, say, a pure CGI animation, but at the moment I think my focus will be on the vital preparation; anatomy, concepting, research, etc.

Anatomy of a Sabre Tooth Tiger

I've spent the last few hours getting reference images for saber tooth tigers and normal tigers and then doing an anatomical study so that when it comes to modelling and animating the creature I'll have be able to do so accurately.

Here's the study:

 I couldn't find any visual reference for the muscle structure of sabre tooth tigers or even just normal tigers so I had to use a muscle structure diagram of a house cat and adapt it to a sabre tooth skeleton.


That's it for now.