LO 1 Understand 3D character modelling techniques used in media products
P1) 3D Character Modelling Techniques:
Research and explain three character modelling techniques used in existing games.
i) Modelling process e.g. Polygon modelling, NURBS modelling, sub divisional modelling, extruding 3D shapes.
ii) Animation / motion Generation e.g. How characters / objects move in a 3D environment, use of lights, cameras, textures.
iii) Application e.g. How and where are 3D characters used in computer / console games, animations, live action.
Create a word document report explaining the three above elements.
Create an analysed report, approximately a page and half with relevant images for each question.
Helpful documents below:
3D Character Polygonal Modelling
http://blog.digitaltutors.com/modeling-with-quads-or-triangles/
Modelling with quads or triangles - what should I use?
Should I use quads or triangles on this model? The truth is, while it can come down to preference, there are some key advantages to using quads to create your models. It’s also not the end of the world – or your model – if you use both, but it is recommended to use as few triangles as possible to save you some major headaches down the line.
Understanding the different polygons.
For a modeller, there are only three polygons that matter.
Triangle
A triangle is the simplest polygon that is made up of three sides or edges connected by three vertices, making a three sided face. When modelling, triangles are typically a polygon type often avoided.
Triangles tend to pose a problem when subdividing geometry to increase resolution and when a mesh will be deformed or animated.
N-gon
An n-gon is a polygon that is made up of five or more sides or edges connected by five or more vertices. It’s important to keep in mind a n-gon is typically related to a five sided polygon, but it’s not limited to just five sides.
A n-gon should always be avoided, they often pose problems at render time, when texturing and especially when deforming for animation.
Quadrilaterals
A quad is a polygon made up of four sides or edges that are connected by four vertices, making a four sided face. Quads are the polygon type that you’ll want to strive for when creating 3D models.
Quads will ensure your mesh has clean topology and that your model will deform properly when animated.
So why choose quads?
When modelling with quads, the wireframe will have a much cleaner look and the model will be easier to navigate and edit. When you spend hours working on a project, you deserve to show it off. But, if the wireframe is messy you become very limited to what you can actually put out in the world for everyone to drool over. When you use quads you create clean, sleek lanes of polygons that are easy to follow through the model and provide beautiful edge flows that you can be easily modified by you or a team member. It is less distracting when you overlay the wireframe on a clay shaded model or even a textured asset. It is also good to work in quads if you plan on passing the model off to someone else or a team. It is easier for someone to convert a model made up of quads to triangles than it is for someone to convert a model made up of triangles to quads.
Edge loops
Edge Loops typically are a continuous loop which no start or end point is determined. If you were to start to follow a loop from a highlighted vertex, you would eventually end up at that exact vertex. Edge loops are helpful to add detail such as wrinkles or folds, they can also be used to help define how sharp an edge is.
If an edge loop runs into a triangle, the loop has to end. This breaks the flow of the line and it’s no longer a loop.
Sculpting
So you want to add that extra little detail to your model, you better use quads. If you plan on taking your model into a sculpting application, such as ZBrush or Mudbox, It is best to avoid triangles as much as possible.
As stated previously, it is easier to predict how the geometry will be affected. Sometimes you may need to subdivide the geometry 4-5 times pushing your model over a million polygons. This is why you want to work with a predictable quad-based mesh. This also helps build a lower resolution version and accent the model using edge loops.
Subdividing
When subdividing quads, your results are fairly predictable. You have rows and columns made up of four sided polygons and it is easy to see where those polygons will be split in half once it is subdivided.
When you subdivide triangles, things tend to get messy. There really isn’t a visual flow to the model.
Smoothing
If you plan on smoothing your geometry or using a quick smooth preview feature, triangles will produce anomalies across the surface of the mesh. Because of the uneven amount of vertices, the triangle can cause blemishes or pinch the geometry. This similar thing can happen to geometry created with n-gons.
Animation
Quads produce cleaner deformations. Typically, artists will focus on areas where there will be a lot of bending and deforming, such as knees, elbows and wrists, and provide a little extra geometry that will benefit the rig and animation. With Quads, this is easily accomplished by adding or manipulating edge loops. If you have a cluster of triangles in this area, it is harder to add or remove loops that will help benefit the animator. With Triangles, it is also harder to see a clean flow of geometry and they tend to produce sharp angles that can harm the mesh’s appeal. When it comes to animation appeal is important both to the model and the artist who provided the mesh for animation.
What about hard surface models?
When modelling hard surface models, the preference is still to use quads. The main reason: so you can quickly add and remove edge loops. When it comes to UV mapping your model, it is also easier when using Quads. There are less edges to clutter the texture editor when placing UVs. Triangles are not a bad thing. They just have to be used strategically throughout your model. When using them on organic models, it is best to hide triangles where they will not be visible or in areas where very few deformations are happening. A good thing to keep in mind when working in Quads is you can always convert it to triangles. There will be times when triangles will be preferred, an example of this is the final mesh of game assets or characters. In these instances most artists still prefer to work in quads and then convert their final model to a mesh built of triangles.
It’s always good to look at how other artists solve topology issues in their work. If you want to go through a series of exercises exploring techniques to create the best topology in your own models, follow along in this skill-builder course on Mastering Topology in Maya. Or if you feel like just going over some quick tips for better topology you can take a look at Modeller’s Toolbox: Topology Tips.You can also explore ways to re-topologise your mesh in Retopology Techniques in Mudbox or create facial animation topology in 3ds Max.
http://www.aliasworkbench.com/theoryBuilders/TB1_nurbs1.htm
Non-Uniform Rational B-Splines (NURBS) and is simply the name for the mathematics that is used to create the geometry in Alias, and in many other CAD systems.
Luckily, no understanding of the math is required to become an expert Alias user. There are a few technical terms that are used for controlling the shapes we design, but they are simply learned as each tool is learned, and don't need to be understood in a mathematical way.
The key benefit of NURBS is that it isn't an approximation of a smooth shape. The math calculates an accurate definition of the surface shape which is still smooth however closely the surface is examined.
(Note: For speed of interaction, the smooth NURBS curves will be displayed as straight-line approximations on the screen, but the actual underlying math, and the resulting product that is manufactured from the data will be smooth.)
Why NURBS is used
More important than the underlying math is understanding what unique features Alias NURBS has to offer you as a designer, compared to the other software tools you may be using:
- Flexibility to create sculptural shapes
- Tension to keep surfaces smooth and taught
- Alignment to create smooth, invisible joins
Designing with this level of attention to sculptural aesthetics is a specialised area of CAD modelling, typically used for premium products where elegance and surface quality are important factors in the product's appeal.
How NURBS is used
A NURBS surface is defined by a network of Control Points. The position of the control points 'pull' the surface patch into a shape, like a flexible sheet.
The key skill that you will develop is choosing the right number of control points, and the right position of each of them to achieve the sculpted surface shape that you need:
The following sections examine how freeform NURBS modelling differs from other CAD and modelling software used for similar tasks.
Comparing Alias NURBS to Engineering CAD software
Most engineering CAD systems use the same NURBS mathematics as Alias does to define the geometry.
This is useful as it makes data transfer between Alias and other CAD systems accurate and complete, without any loss of definition.
However, being based on the same 'material' - NURBS - doesn't mean that the interaction and the results are similar:
Engineering CAD
Most of the geometry will be defined as recognisable geometric shapes.
- Primary Interaction: geometric and dimensional criteria - arcs, ellipses, straight lines, angles.
- Secondary Interaction: freeform shape creation using splines, often this is also controlled through dimensions and XYZ positions
Alias NURBS
Alias NURBS allows the user to sculpt any shape, and is typically used for freeform, sculptural designs that can't be defined by dimensions or geometry.
- Primary Interaction: aesthetic, artistic, sculptural choices of shape and form.
- Secondary Interaction: geometric and dimensional criteria - arcs, ellipses, straight lines, angles.
Comparing Alias NURBS to Polygon Modelling
NURBS and polygon models are typically both used to create freeform designs, but are based on completely different representations of the geometry, and therefore have different methods of controlling the flexibility of the design.
Polygon Modelling
Polygon modelling has traditionally been used in Character Animation modelling and Games modelling as it is particularly good at:
- Creating surface detail (wrinkles in a character's face, vegetation, rocks)
- Fast rendering calculations (polygon models are already tessellated)
Polygon modelling is generally seen as easier to learn and easier to use than NURBS modelling, and because of this, it is beginning to be used more for concept design work.
Alias NURBS compared to Polygon Modelling
Polygon modelling is not used for production quality final designs because of the lack of surface smoothness.
A polygon model is a collection of flat facets that approximate a smooth shape. This is adequate for rendering or prototyping (and in fact NURBS models are converted to a polygon representation for these purposes), but not for production.
The CNC machine tools that create the tooling for final products work from the accurate, smooth NURBS data.
Subdivision Modelling
http://theorangeduck.com/page/subdivision-modelling
History
Subdivision modelling is a technique of digital 3d modelling used to create clean models with scalable detail that look good when rendered. It is used to some degree in almost all industries that employ digital artists. Saying this, it is often at the discretion of the artist or the tool, as to what modelling technique they choose to use. Other popular techniques are per-poly modelling, nurbs modelling and digital sculpting.
The technique and subsequent art of subdivision modelling arose more or less naturally due to several aspects or phenomena in how digital art is typically rendered. The main two examples of this being the default method by which vertex normals are calculated and the way in which Catmull–Clark subdivision (after which the technique is named) works.
An example of a subdivision model
Vertex Normals
A vertex is a point in space where various lines (or edges) meet. They can be thought of as the corners of geometric shapes. When a computer renders a shape on the screen there are two options. Either it can render each polygon (or face) of this shape as a flat surface and do lighting calculations based of that, or it can try to render some smoothed version of the same shape. This second option is often what we want, and this is where vertex normals are used.
If, instead of looking at face normals (the direction the face is pointing), the renderer looks at vertex normals (the direction the corner is pointing) then it can interpolate (a kind of averaging) this direction across the triangular face it is rendering, giving it something of a smooth look. In fact, for any triangle, graphics cards are specially designed so as to be able to do this interpolation the normals from the three vertices at each corner, very fast. This is what happens in all 3d computer graphics, from Lord of the Rings to Quake II.
But, before we can do this interpolation, we have to work out the actual vertex normals to use. To truly find the direction a vertex is pointing is impossible (it has no surface, so has no normal), but what we usually do is simply average out the face normals for all of the faces attached to this vertex - and use this as an approximation for the normal.
This allows us to render smooth surfaces using angular geometry (and a fixed number of polygons), but it does come at a cost. In many cases it does not quite work as expected, and can lead to visual artefacts or sections of the lighting that look weird. These arise from issues with the approximation of vertex normals, and also with the interpolation calculations across triangles. But, with a good mesh, these artefacts can be minimized or even overcome, and this is where subdivision modelling comes in.
Some Terminology
In computer graphics there are new terms for almost everything. I've probably already thrown some new ones at you which I'll revise here, but once you get to grips with these, everything becomes a lot easier to explain. The reason that some of these things have names will also become apparent later.
· Vertex - A point in space where edges meet, the corner of a shape.
· Edge - A connection between two vertices.
· Polygon - A face of a 3d shape, connecting several vertices via edges.
· Mesh - A collection of polygons, a shape in 3d space. Also referred to as a model or a body.
· Triangle - A polygon with exactly three vertices.
· Quad - A polygon with exactly four vertices.
· N-Gon - A polygon with five or more vertices.
· Pole - A vertex with three edges coming out of it.
· N-Pole - A vertex with five or more edges coming out of it
So where does Subdivision come into it?
Subdivision is a process that will smooth a mesh, adding more polygons and vertices while maintaining form. A quad will be smoothed into four quads which continue to follow the contour of the mesh. This process is used in many things from rendering to digital sculpting. It's essentially what allows you to build meshes with a manageable number of polygons, before using subdivision to make it as smooth as is visually needed.
Boots Mesh
Boots Smoothed
Subdivision, much like calculation of vertex normals, is not perfect. You get artefacts in many of the same ways. Also, any artefacts from vertex normals in the original mesh (at one subdivision level), will remain once subdivided (at the next subdivision level). There is a beautiful symmetry in how this works. On subdivision, Triangles become Poles and N-Gons become N-Poles. The opposite is also true. Poles become Triangles and N-Poles become N-Gons. Because of this, quads are the only thing that subdivides "perfectly", and so having quads in your mesh at all the key locations, which define the form and smoothness of the surface, is essential.
L02 Be able to plan a 3D modelled character for use in a game or animation
P2, M1) Plan for a 3D modelled character for use in a game or animation.
a) Genre –
i) Children’s Animation
b) Character profile –
i) Consider physical / emotional attributes
ii) Provide description of the character
iii) Special characteristics, gender, age, clothing and props
c) Series of character visuals –
i) Rough character sketches
ii) Storyboard depicting the character movement, interaction with their surroundings
d) Target audience –
i) Consider audience appeal, lifestyle, age, gender
BBC CBeebies wants you to model a snowman character for a potential new show for Christmas 2017.
The snowman can be male or female, but must have a friendly look. The clothes, eyes, nose and mouth can be textured in any colour.
Snowman must be able to move from right to left and in a full circle. Snowman must also in the animation head a football on their head and shoulders.
Place the snowman in a simple snow filled environment.
Therefore BBC CBeebies want you to animate the snowman character doing the following:
a) Moving their body around
b) Moving their head around i.e. Spinning head, rolling head
c) Heading a football with their head and shoulders
d) Ball knocks either snowman’s hat, nose, buttons etc.
e) Any other animation of your choosing
DESIGN PRE-PRODUCTION:
Create the following pre-production elements to show how you will plan to create your snowman character and animate them.
a) Genre –
i) Write a page and a half regarding what the genre of your snowman character /animation will be
ii) How the character / animation fits in the BBC CBeebies children’s programming?
Visualise page.
b) Character profile –
i) Write a minimum of two pages explaining your snowman character /animation.
Consider: Physical and emotional attributes, full description of the character, special characteristics, gender, age, clothing, props
c) Series of character visuals –
i) Create six snowman sketch images
ii) Twelve panel storyboard depicting character movement and interaction with their surroundings and prop.
d) Target audience –
i) Snowman character appeal to children and adults / parents
ii) Lifestyle of children and why that would inform their liking of snowman character
iii) Age and gender of children and adults / parents
LO3 Be able to construct an animated 3D modelled character for use in a game or animation
P3 P4, M2, M3, D1, D2) Construct a 3D character
in Maya using modelling tools
for a CBeebies show.
i) Watch youtube snowman character building videos and follow the video course until completion of your snowman character and environment.
ii) Once completed, re-model snowman character to relate to your pre-production sketches.
iii) Texture (colour) the character and clothes.
iv) Use Maya camera and animate snowman looking around and heading a ball on their head and shoulders / anything else you feel confident animating and have depicted in your pre-production materials.
LO4 Be able to produce a how to guide to illustrate the process of creating a 3D modelled character
P5, M4) Produce a step by step ‘how to guide’ on how
you created a 3D character and animated
them using. Use illustrations, own written
text and images individually created.
a) Use the below how to guide as an example:
http://www.3dtotal.com/tutorial/2162-a-step-by-step-guide-to-modeling-the-base-mesh-of-low-poly-game-character-part-1-3ds-max-zbrush-by-gavin-goulden-swordmaster-model
Step 17
With half of the face complete, you need to connect both sides. In the Modify panel, right-click Editable Poly and select Make Unique. This causes the object to no longer affect its instance. It also allows us to attach one model to the other (Fig.19).
Step 22
Extrude edges from the base of the clavicle all the way down to the waistline, adding a slight indication of where the chest will protrude. Using the side reference shot as a guide, begin to block in a loop for the entire waist. This quickly helps to show how wide the character will be and will also act as an anchor for connecting edges to the chest and legs (Fig.24).
Step 24
From here define the mass of the deltoids. I like to create a loop that circles the upper portion and loops around the arm. This comes mainly from an animation standpoint that has carried over to my base model creation technique, but it also helps to define the valley where the clavicle, trap and deltoid meet (Fig.26).
Step 25
To complete the body, the rest of the work is really just filling out these major points that we have defined with clean topology, keeping the mesh equally dense and composed of four-sided polygons. Much like the shoulders you should define the hips with a loop that will circle the legs. I also like to continue the edge flow of the shoulders across the entire back (Fig.27).
