Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. If you continue browsing the site, you agree to the use of cookies on this website. See our User Agreement and Privacy Policy.

Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. If you continue browsing the site, you agree to the use of cookies on this website. See our Privacy Policy and User Agreement for details.

Like this presentation? Why not share!

398 views

Published on

No Downloads

Total views

398

On SlideShare

0

From Embeds

0

Number of Embeds

2

Shares

0

Downloads

6

Comments

0

Likes

1

No embeds

No notes for slide

- 1. CREATING A 3D IMAGE Michael Heron
- 2. INTRODUCTION In this lecture we are going to look at the process we go through in order to build a 3D image. At least in theory. Will need to wait until the lab before we do it For Reals. Two main techniques for doing this. Line Mode Box Mode
- 3. TERMINOLOGY Face A simple shape used to make up a more complex shape. Also known as a polygon Vertex A corner point of a polygon Edge A line represented by two connected vertexes
- 4. CREATING A 3D OBJECT We need to do several things. Define the geometry of the shape. Apply transforms to set Location Scale Rotation Define surface details. Textures We do this for each object in a scene. We’ll talk about only one.
- 5. DEFINE THE GEOMETRY How do we define the geometry? We choose between two main ways. Or a hybrid of the two. First way is to draw each point in the shape. For large, complex shapes – extremely difficult. The more polygons we have, the more difficult this becomes. This is the line mode of drawing shapes. There be dragons.
- 6. DEFINE THE GEOMETRY How do you sculpt an elephant? You take a block of marble, and chip away all the bits that don’t look like an elephant. This is the Box Mode of drawing shapes. Start with an approximate shape. Usually one of the standard geometric principles. Manipulate it until it fits your needs. Or at least, closely approximates your needs. Recommended approach.
- 7. DEFINE THE GEOMETRY A third way is to make use of a representation of a real object. Requires the use of specialised hard-ware Which you don’t have. The method you choose depends on The nature of the object Requirements of the model. A hybrid approach is usually the best Start with a rough shape, draw extensions to handle fine detail work.
- 8. 3D REPRESENTATIONAL FORMS Several ways to represent 3D Geometry: Polygonal. Objects approximated by nets of polygons A polymesh Bicubic Objects represented by nets of curved patches. Constructive Solid Geometry Constructed from sets of basic geometric shapes Space subdivision Ray-tracing We focus primarily on polygonal today. Talk about the rest in the next lecture, or thereabouts.
- 9. SIMPLE POLYMESH (x1,y1,z1) (x2,y2,z2) (x3,y3,z3) (x4,y4,z4) (x5,y5,z5) (x6,y6,z6) (x7,y7,z7)(x8,y8,z8)
- 10. SIMPLE POLYMESH – LOCAL CO-ORDINATES (0,0,0) (50,0,0) (50,0,50)(0,0,50) (0,50,0) (50,50,0) (50,50,50)
- 11. SIMPLE POLYMESH - REPRESENTATION object surfaces polygons vertices
- 12. SIMPLE POLYMESH - REPRESENTATION Represented by a face-vertex mesh A list of faces represented by vertexes A list of the vertexes and what faces they are part of Co-ordinate space of each vertex. This provides a mathematical, context independent representation of an object in its own local space.
- 13. FACE-VERTEX MESH
- 14. POLYMESH NOTES Shape is only an approximation for complex images. Can’t represent a circle. Can represent something that is almost a circle Level of approximation dictated by polygon count. Shading and other detailing approaches can help to hide shape approximations. Ubiquitous representation. Graphics cards usually include specialised hardware for rendering large numbers of polygons.
- 15. DRAWING AN OBJECT Begin with simple starting shape. Want to draw a head? Start with a sphere. Can add a sphere as a base shape in Blender Consider necessary transforms. Can do vertex, edge, and face manipulation on polymesh shapes. Can apply basic transforms to part of a shape. Can also extrude. Used to extend a part of a shape.
- 16. DRAWING AN OBJECT Can also spin basic shapes: http://en.wikibooks.org/wiki/Blender_3D:_Noob_to_Pro/Modelling_a_Mu g_using_Spinning_and_Extrusion
- 17. DRAWING A SHAPE Blender provides many different modifiers to change the basic structure of how you interact with a shape. Mirror allows you to mirror modifications across a shape. Subsurf makes a rough image much smoother and more organic. Lots of these modifiers Experimentation is the key
- 18. MODIFIER - SUBSURF
- 19. MOLDING A SHAPE Back to the elephant. How do we turn a simple shape into what we actually want? Begin with a sphere Elephant body Select appropriate faces on that sphere. Extrude into legs Add another sphere The head Extrude a trunk Extrude a tail The rough work is handled using these kind of processes.
- 20. EXTRUSION Extrusion is one of the most powerful tools you have available in blender. Pick a face, and extend it outwards or inwards. Used to raise and lower surfaces. Can be used to create entirely new surfaces. Used to create shapes where shapes did not previously exist. For example, in the coffee cup.
- 21. EXTRUSION
- 22. TEXTURING Once you have a basic shape you want to make use of, you can apply various textures to it. This changes the colour, and how it interacts with light sources. A base blender scene has three elements. A light source (by default, the sun) A camera A shape
- 23. TEXTURING The texturing system in Blender is extremely rich. You can set how your object interacts with light You can set the specific kind of rendering to be done You can choose transparency and type of textures. Most of these will not be visible except in preview until a scene is rendered.
- 24. TEXTURES Importantly, we can also make use of predefined bitmaps for a texture. We can make use of our own images which get layered onto the shapes we provide. We’ll see more of this later lectures and labs. It’s not a simple concept and easier to understand when shown rather than simply described. Experimentation very important. Can’t even begin to cover what Blender makes available!
- 25. SUMMARY Polymeshes are the graphical representation must used. We’ll talk about the rest later. 3D Object created by: Representing geometry Applying transforms Applying textures Rendering

No public clipboards found for this slide

×
### Save the most important slides with Clipping

Clipping is a handy way to collect and organize the most important slides from a presentation. You can keep your great finds in clipboards organized around topics.

Be the first to comment