Scripting Tool Interface

I have already got a good idea of how I want the user interface for my script to work so I have been able to build this using python scripting. The functionality of the tool is non existent but you can get a better understanding of how it might be interacted with.

I had some trouble getting the layout I wanted initially. The 'columnLayout', 'gridLayout' and 'rowLayout' options weren't working out for me and using tabs or drop down frames wasn't what I wanted either. To get a move on with the interface I used a 'formLayout', although it took slightly longer to code it was easier to get the result I wanted.

The interface itself is pretty close to the sketch I did earlier and I think overall should be easy to understand by any user familiar with Maya.

In the first section of the layout the user can select the type of control shape they want to make, by default it is a 'General Handle' which in this case is a NURBS circle. A 'Rotator Handle' can also be chosen which I described in my last scripting tool progress blog post.

For both shape types their radius can be chosen in the text input box and I've also included a check box here if you want to setup an orient constraint connecting the shape and joint. I initially had this feature locked to the rotator handle only but quickly decided it would necessary to orient constrain shapes other than the rotator type.

A separator separates the shape type options with the additional options. This currently includes the ability to colour the control shape. Right now I plan to have the colour automatically selected and applied depending on where the joint is: blue on the left side, red on the right side and yellow for central shapes. As a more advanced feature I could allow the user to select the colour themselves through a colour selection UI but for now I'm happy with the automatic as it will be useful in my own rigs.

Locking translation controls is also useful especially for joints with an orient constraint so this will simply lock and hide the translation attributes from the control shape.

In addition I've included the option to override the automatic name given to the control shape. The script to create control shapes which we used earlier in the semester automatically names the control shape after the joint. My thought behind the custom name was where when I used this script in the past I sometimes wanted a different name for the shape. Example: a control shape assigned to jnt_head_2 might want to be called ctrl_head_top.

I think the userface's design resembles that of what most Maya windows look like. I've also contained both the 'Create' and 'Add' buttons at the bottom (many maya windows have this) where they both apply the create operation but 'add' keeps the window open so you can perform multiple uses of the tool.

My next step is to simply implement the creation of control shapes into the buttons, then work down the list of features on the window adding in the relevant functionality.

Pseudocode

For the functionality of my scripted tool I've written some pseudo-code (in python format) that will guide me in programming later on.

This handles functionality of creating control shapes as well as user interface elements.

• import maya commands

• define function name_check_select
• enable name_input textField

• define function name_check_deselect
• disable name_input textField

• define function create_control
• joint_name from selection
• joint_name_stub = replace "jnt" with "" in joint_name
• current_ctrl_shape = "ctrl" + joint_name_stub
• current_group = "grp" + joint_name_stub + "offset"

• radius = radius_input from textField
• if radio_general radioButton is selected
• create nurbsCircle with name current_ctrl_shape and radius of radius
• if radio_rotator radioButton is selected
• create nurbsCircle with name current_ctrl_shape and radius of radius
• delete history on current_ctrl_shape
• duplicate current_ctrl_shape with temporary name circle_1
• duplicate current_ctrl_shape with temporary name circle_2
• rotate circle_1 by 90 degrees in X axis
• rotate circle_2 by 90 degrees in Y axis
• freeze transformations on circle_1
• freeze transformations on circle_2
• parent the shape node of circle_1 to current_ctrl_shape
• parent the shape node of circle_2 to current_ctrl_shape
• delete circle_1 transform node
• delete circle_2 transform node
• create a group with name current_group for current_ctrl_shape
• parent current_group to joint_name
• set rotateX attribute on current_group to 0
• set rotateY attribute on current_group to 0
• set rotateZ attribute on current_group to 0
• set translateX attribute on current_group to 0
• set translateY attribute on current_group to 0
• set translateZ attribute on current_group to 0
• unparent current_group from joint_name

• if window wnd_control_maker exists
• delete wnd_control_maker
• create wnd_ctrl_maker

• create buttons, radioButtons, text and textFields
• position buttons, radioButtons, text and textFields on form

• show wnd_control_maker

Scripting Tool Ideas

For my scripting tool the idea I wanted to make was an assisting tool to making control shapes.

For the character rigs in my Professional Project the control shapes are mostly for FK rotation rather than the IK solvers used in my rig for this module.

I've found that the easiest rotation control shape looks like the rotate tool itself which is made up of 3 circles. To make this manually is on the complicated side and even requires the use of a command.

How this control shape is made is by creating a NURBS circle, duplicating it twice and rotating them into position. You then freeze transformations on these circles and delete their history. To combine them you combine their shape nodes under the main circle's transform node. Then, it is like any other control shape that requires grouping and positioning.

I would also like to include other options such as locking translation controls, automatically Orient Constraining the joint to the shape and colouring the control shape.

This is a sketch of an interface I'd like to aim for, it also includes some notes on the functionality of the script.

Looking at Other Scripts

For inspiration into my own scripting tool I did some research into other tools out there that are designed to assist in the rigging process.

There is definitely a lot out there, ranging from simple scripts that can solve a simple problem to complex tools that can automate most of the rigging process. The type of tools and where they are used can vary, with some tools being used to interact with a fully built rig, to others that help build the rigs.

Here's a few I found with some notes on their uses in relation to my own work so far.

Display Color Override

A neat little script that displays a colour index UI used for easily selecting a colour. This is used for objects such as control shapes to change their colour rather than having to go into the attribute editor and using the slider to find the colour you are looking for.

Radial Blend Shape

Useful tool that assists in setting up facial deformers such as eyelids and eyebrows. The deformer is suited to keeping eyelids deforming properly (i.e. over the eye).

Control Curve Creator UI

A similar scripting tool to what I imagine I want to create. This is quite extensive offering multiple shape options, a colour selection grid and additional options such as auto/manual name toggle and adding text.

This script only creates the control shapes for future use in rigs, it doesn't apply them to any joint.

Biped Auto Rigging Script

Create a full rig or a specific part of a rig, can rig characters in any position and is fully scalable. Allows IK/FK switches and other features.

One of the many auto-rigging tools out there, this was created by a student. Is pretty comprehensive but other auto-rigging tools have gone much further.

Rapid Rig: Poser

The only scripting tool on this list that costs money. This is a UI designed to enhance animation and allows the user to save out poses on a character rig. It also allows you to mirror a pose across the body and to transfer poses to other rigs.

It also acts as a picker allowing you to select control shapes from a user interface. This script is by far the most advanced and comprehensive script on this list but it does have dependencies on other tools.

This is a companion tool to the Rapid Rig: Advanced script (another auto rigging tool). Poser tools are often tied to the rigs they are designed for.

Blend Shapes

As my character rig is for animated films rather than games, I will be using a blend shape system for facial controls over a joint based system. Blend shapes work a bit like keyframes, where you set multiple poses on different faces, then on the main face controller you can blend between them.

The 'MikeAndTina' and rig I've mentioned previously uses blend shapes combined with a floating interface for interacting with these blend shapes. For now I've built the control shapes and will consider any user interface as an advanced feature later on.

As the mesh for my characters face is included in the mesh for her entire body, I had to extract the head from the body to be able to use as a blend shape. I used this YouTube video to work out how to extract the head. I discovered an issue with my character model that was seemingly unique to this model whereby when I cut the head from the body using 'Detach Component' the skin shader would seemingly trip out and produce a strange pattern. I tried troubleshooting many ways to fix this including removing all shaders, applying new ones, changing display modes and looking at vertex colouring but there seemed to be no fix. I had to re-import the skin mesh from another exported version of the character model for it to work. Thankfully it did work out in the end but I still haven't worked out where the issue came from.

Once my the head was detached and duplicated, I re-combined the original meshes (making sure to do so correctly without changing the vertex names) and merged the vertexes back together on the joint. The duplicated head would not be a blend shape itself but would be a base mesh for blend shapes to come off from that. The base head would then connect itself to the main mesh so to transfer the blend deformations over when used.

Blend shapes is another thing that a lot of time could be spent on. Many rigs that use blend shapes have a comprehensive selection of deformations that can be controlled. As my time was limited and I wanted to move on to skinning I decided to create a selection of blend shapes that would cover most facial expressions but that may not be as extensive as other rigs. However if time was given, creating more blend shapes from the base head is always a possibility.

In total I have 14 blend shapes that control the opening of each eye, the raising of each eye brow, mouth raise on both sides, a pout and wide mouth position, and a few more.

The soft selection tool came in handy here, in surface mode it was useful for opening the eyelids as well as deforming the shape of many facial features.

If I were to add more blend shapes I could add more deformers to the eye brows to change their shape, controls for cheek muscles, more mouth deformers, nose deformers and more eye lid deformers. All of these take time so I will consider adding more later if time permits.

Spline IKs and IK Solvers

My rig's skeleton and control shapes are progressing well but I've fallen behind on adding in IK solvers. I've taken the time to set these up before moving into the advanced features and setting up the hierarchy of controls.

I should mention I have now set up my spine. This uses a Spline IK connecting the bottom and top of the spine joints. Clusters are added to control three different parts of the spine. The middle controller automatically positions itself between the other two controllers.

Using the connection editor I've also added twist and roll setup to the spline controllers for additional functionality.

I had some trouble with this whole procedure having to re-do the process when I didn't correctly position the control shapes. I almost had to re-do the procedure again but using freeze transformations on the controllers (which had somehow again de-positioned themselves) I was able to avoid that. This is something that could be automated easily for a scripting tool. I may want to consider that if it decides to break again.

I've had to return to IK solvers as somehow was unable to build them when they were discussed in class initially. I think this has to do with how long it took me to do the set driven key (which is quite tedious) and learning the ropes about building control shapes.

Its been a while since IK solvers were mentioned so I've looked over the documentation on them and brushed up my knowledge on how to build them. I've now added IKRP solvers on the legs and arms, and two on each feet to stop them from rotating when I move the legs. These extra IK solvers will be used when I add advanced attributes to the feet later on.

Another issue to mention here is that my character model's feet point out to the side a bit instead of straight ahead. This along with the joint orientation means when adding in a pole vector constraint the leg tends to rotate out of position. I was initially unable to fix this (others had this problem and scripts were being used) but I just translated the rotator along and it rotated the foot back into position (although not back in the exact same position, I remember this is not entirely necessary, it was good enough). It does mean my knee locators are not located in front of the knee but instead are a little bit off to the side. But if the feet are not pointing forwards then the knee isn't either so I am happy this will be fine to work with.

I had the same issue with the wrists snapping out of place when adding a pole vector constraint but learned that adding an orient constraint between the joint and the wrist first before adding the constraint meant no joint movement occurred.

Technical Artist Research

This is a post mostly looking into Technical Artists in the industry.

Technical Artists are considered the connection between artists and programmers. They help to ensure assets can be imported into games and work correctly within the limitations but not hindering the creative vision.

They are also the researchers and tool designers. This is something we've seen an example of in our own coursework, where somewhere along the rigging process we'll find ourselves in need of a tool to help with that process. Improving pipelines is obviously more efficient to the process but can also help alleviate workloads by automating certain aspects of the process.

This year I've been learning 3D animation myself by optionally attending the Advanced Animation module. Through that I discovered the Mery rig which of course I am using the character model to rig myself to learn the process. The Mery rig is very advanced for something you can freely download on the internet and has been credited for being built to a very high professional standard. I mention this because it was only created by two guys and so far is the most robust and advanced free rig I've found.

Recently Sony Pictures Animation released a zombie rig from their Hotel Transylvania film. This was the first I'd seen of a major studio releasing something like this for anyone to try out. In the demonstration video one of the animators walks through the features of the rig. This is sort of evidence that the work of a technical artist to create a rig with a large variety of features pays off by making the job easier for the animator.


I've also discovered some information on DreamWorks website about technical art, particularly the process of creating character rigs. Artists are actually hired under the title of "Character Technical Director" (TDs) and can spend between three and six months of time on each character.

As their film "The Croods" required about 35-40 unique creatures the Character Technical Directors came up with their own package called the Creature Assembly system to help with this process. By storing information on different limbs and creature parts (wings, tails, etc.) they could mix and match them, analyse how they interact together and connect them up appropriately.

I'd highly recommend giving this article a read as I found it interesting and informative on the topic of character rigging: https://web.archive.org/web/20141214215455/http://www.dreamworksanimation.com/insidedwa/tech/cas

I'll leave you with a demo reel from Technical Artist Tim Carter who shows off some of the things he's created. This includes rigs he's made and their advanced features as well as dynamic cloth, scripts and some problem solving rig features such as no-flip elbows & knees.

Creative Skillset profile on Technical Artists: http://creativeskillset.org/job_roles_and_stories/job_roles/339_technical_artist_games