This is an excerpt from Tradigital Maya by Lee Montgomery. Here Lee explains thumb-nail sketches and how they can be useful resources when working in 3D.
Thumb-nails are quick and simple sketches, which help to establish or layout the motion in a shot. The definition of a thumb-nail sketch is a small (thumb-nail sized) sketch of the motion or framing. You can use traditional media such as pen and paper when creating thumb-nails or alternatively use a graphics tablet on the computer. Using a graphics tablet has the advantage that you can also quickly make revisions to animation through using screenshots or renders of the animation with the action re-drawn as an overlaid layer in painting package. Let’s take a look at a couple of different areas you can apply thumb-nails when animating.
Overall Motion Planning
Thumb-nails can be used to block in animation from Pose-To-Pose in sequence. For example, for the jump animation and run-cycle thumb-nails were used to pre-visualize the overall posing and motion. Thumb-nails were used to establish both the overall distance of the jump over the sequence (see Fig. 5.1.1) as well as specific posing, weighting, and balance at the end of the sequence (see Fig. 5.1.2). When working on rough thumb-nail sketches to establish overall motion, the sketches can be pretty rough as detail is not required. Simple block figures or “Stick-man” style drawings can be sufficient when blocking out character animation with thumb-nails.
Character Posing – Rig Balance and Weight
Thumb-nails can also be used during the editing and refinement phase of animation. Where more detail is required, they can be used to figure out the pose at a particular frame. Figuring out the line and angle of the shoulders and hips for character animation is critical in planning out poses that look weighted and balanced. Shifts in the shoulders and hips need to correspond with the major weight shifts on the foot plants. For example, for the run-cycle, they were used to figure out the pose and rotations on the character’s spine, hips, and shoulders during the major contact poses when the legs and arms are fully extended (see Fig. 5.1.3). Overall, thumb-nails should be considered as an extension of your thought processes and are really just a tool to help figure out what work needs to be done or revisions made.
Reference for Animation
When working in 3D, it is important to have a game plan when working out the character pose or shot. For character animation, you can use thumb-nails as reference, to block out and validate the posing as well as to make revisions while animating. This can be really useful when working on the posing of major areas such as the angle or curvature of the spine as well as the rotation of the torso and hips during a run (see Fig. 5.1.4).
Roughing out some quick thumb-nails while animating can also be a great aid when you’re stuck on the posing for a particular shot or need to make revisions. You can quickly make comparisons and revisions when evaluating the animation in 3D while sketching out the major changes to the pose for the character and rig. For detailed refinement, it can be worth appraising the posing and thumb-nails from several angles to make sure the poses look balanced and poised (see Figs 5.1.4 and 5.1.5).
Life-Drawing and Study – Figure and Form
For character animation, it is worth in considering life-drawing classes to study human anatomy and form in more detail. Most life-drawing classes include a warm up section, where you work on a series of shorter sketches. This can really help in sharpening up your drawing and observational skills when it comes to animating (see Figs 5.1.6 and 5.1.7).
It can also improve your skills when it comes to quickly blocking in a character pose, whether it is as a quick thumb-nail without reference or in 3D in Maya on a complex character control rig.
Video and Photo Reference for Thumb-Nails
When animating, it is important to have as many tools or aids at your disposal as possible to help in analyzing and refining the motion. This is especially true if you are new to animation and particularly true if you are new to computer animation.
When working in 3D animation, it is easy to create animation quickly due to the tools that are available – you can quickly block in a shot and let the computer handle the key interpolation between frames. This isn’t the case with traditional Cell Animation, where animators are required to draw each individual frame in sequence. Due to this, it can be easy to forget the traditional skills of thumb-nailing and draughtsmanship when animating in 3D. Sometimes 3D animators feel that they should be able to get quicker results that are more final without the additional prework traditional animators would need to do in planning a shot or motion through thumb-nails. In addition to using thumb-nails and reference from life-drawing for character animation, it is also worth using Video or Photo Reference in conjunction with thumb-nails to block out major poses for character motion.
Video or photo reference is ideal when working on physical or extreme motion such as animations of characters performing fast actions or sports. For several of the exercises in the book, such as the baseball sequences, video and photo references were used to help in blocking out thumb-nails. This helps in understanding the major poses and contortions of the body, which can be pretty extreme when the motion is fast (see Fig. 5.1.8). When animating, you need to have a clear understanding of the overall mood and feel of the motion you’re working on. Having great reference and thumb-nails for extreme motion is critical in allowing you to feel out where the major shifts in weight and balance are.
Thumb-nails – Cartooning, Character Detail, and Self Portraits
In addition to the use of thumb-nails as a tool to study extreme or exaggerated body motion, you can also use sketching or cartooning to study more nuanced or detailed areas of human motion. For example, if you’re working on secondary motion for hands on a character or want to add more nuance to the performance take a look at the types of poses your own hands can make (see Fig. 5.1.9). Quick thumb-nails or cartoons showing the poses can help in the planning and refinement phase for the animation. As with other areas of character animation, it’s really worthwhile to act out the motion yourself to get a feel for how the body moves and range of motion you can create. Many animators like working with a full-length mirror close by, so that they can perform full-body motion and use this as a mental note for reference when animating the character in 3D space.
For facial animation, a lot of animators recommend to have a mirror beside the monitor to compare the range of facial poses to real life while animating. Studying the facial poses from a mirror can also be used in conjunction with thumb-nailing and cartooning to create a reference sheet for the range of poses you want for the character (see Fig. 5.1.10).
As with full-body motion, cartooning or thumb-nailing can be used to work out specific shapes for facial animation for detailed areas such as the eyes, eyebrows, and cheeks (see Fig. 5.1.11). This really helps when you’re working out the range of motion the character will need when creating and refining blend shapes for facial animation. As mentioned before, having a game plan for what you want to achieve at each stage of the work helps clarify what you’re doing and the direction the work’s headed. For example, will the character’s personality demand that he is quizzical, surprised, shocked, or angry? – can acting out these poses in front of the mirror and creating reference thumb-nails help?
Skeleton and Rig Design
Another area of production that thumb-nails can be used on that a lot of people overlook is in planning and creating a character skeleton or control rig. In fact, thumb-nails can be used for any rig design or control setup to plan out which controls are needed and where they should be placed for ease of animation.
For a skeleton rig, it is really important to be aware of where the skeleton joints should be created for the character to follow the proportions and form of the character model. Skeletons that are badly placed or misaligned can create bad deformations on the character when animating. For this, you can use thumb-nailing to draw over a print or screenshot of the character model viewed from several different angles in Maya. Photoshop or any other modern digital painting application allows drawing on layers. You can use this to block out the joint placement relative to the proportions on the character then use this as reference when creating the skeleton rig in Maya (see Fig. 5.1.12).
Similar workflow can be used to design effective control rig objects for character rigs. For example, you can quickly thumb-nail out where the control rigs should be placed for the character for logical ease of selection and manipulation (see Fig. 5.1.13). As with thumb-nailing for animation, you can use this when working on detail areas for the skeleton and rig to figure out how you want the setup to look and work.
As mentioned before, the thumb-nailing process should be considered as a visual mental note to help in planning and revision. Time spent working out how you want the rig to look and work will lead to a more effective setup and less time spent making revisions when it comes to actually creating the rig and control object setup in Maya.
Lee has worked professionally within the 3D Animation and VFX industry for over 9 years. Prior to joining Autodesk he worked as a Senior Animator and Artist on a number of high-profile AAA video game titles for well known studios. Notable titles he’s contributed to the hugely successful Grand Theft Auto and Manhunt Video Game series for Rockstar North. His background in production also includes experience in setting up mo-cap pipelines for game cinematics from shoot to edit and in-game implementation utilizing Vicon/MotionBuilder/3ds Max/Maya