BA2 - Lecture: Subdivide and Conquer!

Weekly Tuesday Lecture: Subdivide and Conquer! Digital 'Objet d'art' (Notes and Research)

Form:

Shape, size. Function, anatomy, e.t.c.

Surface: The surface texture. Pores, wrinkles, scratches, scars, wood-grain, e.t.c.

Substance: The material the object is made of: Wood (Oak, Pine, Balsa), Metal (Aluminium, Iron, Steel), glass, skin, e.t.c. Colour: Frequency of light that is reflected (absoption) Defined by a shader and texture maps. R = ~700 - 635nm

G = ~560 - 490nm

B = ~490 - 450nm

Optimisation: For rendering and editing. (High poly - Keep in mind how it moves) 60 Frames per Second

The first Digital Model used in film was 'Future World'

• Polygons

• NURBS

• Subdivision - Surfaces (Catmull Mark)

Object Types:

Polygon Divisions: Smaller - Quicker to render

Higher - Slower to render / More detail

Adding more information to a polygon object adjusts the silhouette.

Polygons are like 3D dot to dots. Limited resolution. More points = More information and Higher Detail

Doesn't relate to quality (Topology) NURBS Mathmatically calculted

Problems - Flat surface wrapped to a shape - Doesn't join up.

Patches multiple surfaces aligning together

Holes appear when you animate and hard to set up properly

Great however, for architectural visualisation

Not used in digital sculpting or a real time engine - too expensive to render

Subdivision Surfaces

Advanced Polygons - Additional vertices. Easy to manipulate and can be creased.

Pixar use Open Subdiv, which is a hardware implementation of subdivison surfaces.

This creates a fast number of Polygons quickly.

Voxel

Volumetric Pixel (Think digital cubes) zBrush Skin - Surfaces - Video = Mass Underneath / Volume there

Limited resolution. Think DPI dots per inch.

More points = More information = Intense. Think about surface and everything within it.

Processor Memory Intensive

Not often used in real time engines - Delta Force 4

• Dot To Dot

Without enough information (Dots), you cannot define form.

Object Components:

Vertex:

A single point. Location of 3D space. Where lines intersect.

Defined Euclidean Space ( x , y , z ) Identify a location using space. 3 Axis, using Cartesian Co-Ordinates ( 0 , 0 , 0 )

Underlying Mechanics

Edge: Line between 2 vertices. A single edge has no volume.

Face: The geometry. Trangles on a single sided surface.

Light bounces off one direction of a polygon.

Polygon: Multiple conjoined face.

3 Sided - Tri , 4 Sided - Quad, 5 Sided - N-Gon (Bad)

Bad N - Gons

Single sided face polygons

Break shapes into triangles

Everything must be rendered with triangles. Always flat.

Advanced Components (Polygons) Green Lines - Surface Normal Must be Perpendicular (90 degrees towards the surface) Same direction the face is facing

Vector (A direction) zBrush - Enables me to see the lighting - Predicting where you can move it

zBrush - In 10 Years has evolved Traditional digital modelling - Primitive

Cube Sphere Cylinder - One torus

Utah - First to exist - Teapot, Monkey

Custom DIY

Box - Pull face out

ZBrush - Dynamesh.

Primitives: Cubes and spheres

Chop it up to start sculpting, then dynamesh, then import polygon mesh.

• zSpheres

• Shadow Box

• 3DWally.com

• Work Low res to High res

zSpheres The Good: Quick to block out ideas

Easy to manipulate, resize and rotate

Maintain proportion

Defines clean topology

Press 'A' for a preview

Great for Limbs

The Bad: No numerical control

Volume does not always translate as expected

Not ideal for flat surfaces (Ex. Wings) The Ugly: Fiddly

Adaptive or unified skin

Used to rig and pose models clumsily

Dynamesh

The Good:

Allows for creativity.

Great for sketching, blocking, form finding. Test ideas. Used to boolean - One object to affect another The Bad:

Not great for detailing

No attention to topology

Can create hopes of the objects volume - Too thin The Ugly:

Patience needed.

Hard surface can be tricky to master.

Shadow Box

The Good:

Hard Surfaces

Scupting Package - Interim Components

3D silhouettes

Mechanical shapes using radial symmetry The Bad:

Doesn't retain crisp edges due to resolution

Geometry

Things to Remember:

- Read the manual

- Look at tutorials

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