December 14, 2010

3D Concepts

Modeling: Modeling is the essential part of 3D. You'll always need to create geometry for your scenes. Even if you are re-using or purchasing a model you might need to make changes on that model to adapt to your scene. The following methods I'm going to explain based on polygonal modeling. Some 3D applications using a mixture of creation methods such as NURBS. NURBS = Non-Uniform Rational B-Splines and uses curves instead of polygons to define surfaces. NURBS can be used to create soft organic surfaces. But lately the CG world moved to polygonal and sub-division modeling rather than NURBS to create organic models such as characters and creatures. Here I only mention about the methods I've experienced with.

- Subdivision Modeling: Sub-D (in short) is all about creating a polygonal cage around a smoothed poly surface in order to manipulate that high resolution geometry. When you convert your object from poly to sub-d you'll have this process automatically done then you can switch to poly editing mode to use poly tools on a sub-d object (Maya). Or you can put your poly object into a Hypernurbs modifier and make it editable to start using polygonal modeling tools on it (Cinema 4D) or hit tab to switch to sub-d modeling mode (Modo). The tools and names changes, workflows are different from software to software but the techniques are the same. When you learn the logic, reason and idea behind a modeling method you can do the same things in many different software.

- Box Method: With utilizing sub-d you can start with a simple box and add details later increasing the sub-d level and transform the polygons to bring out the shape you want from the box. The point is; that you start with a simple box and make it more complex as you go along. Also the base shape doesn't have to be a box, could be a sphere or cylinder. When you get more experience on modeling you'll understand at a glance which primitive base object you need to start with.

UV Mapping: Second step after modeling an object is creating the coordinates to apply texture maps to it.

The process of UV Mapping transforms the texture map onto the 3D object. In contrast to "X", "Y" and "Z" Cartesian Coordinates, which are the coordinates for the original 3D object in the modeling space, another set of coordinates is required to describe the surface of the mesh, so the letters "U" and "V" are used.

UV texturing permits polygons that make up a 3D object to be painted with color from an image. The image is called a UV texture map, but it's just an ordinary image. The UV mapping process involves assigning pixels in the image to surface mappings on the polygon, usually done by "programmatically" copying a triangle shaped piece of the image map and pasting it onto a triangle on the object. UV is the alternative to XY, it only maps into a texture space than into the geometric space of the object. But the rendering computation uses the UV texture coordinates to determine how to paint the three dimensional surface.


- Resource: Wikipedia

Till the days of powerful alternative UV tools such as Headus UV Layout, UV mapping was a tedious and long process. All the 3D artists know that it can be a nightmare. Especially on complex surfaces or scenes with LOTS of objects. Most of the programmers, MEL Script experts (Maya's scripting language) and software houses like Maxon and Luxology (makers of Bodypaint and Modo) worked hard to make that process easy. Now it is. You don't have to think about how you'll handle the UVs. On Cinema 4D or 3ds Max you can use the uv map modifiers to define the coordinates of the surfaces for simple geometries like boxes or tubes/cables.

A plugin named UV Master for Zbrush (a free plugin) designed and created by Pixologic is able to create usable UVs for organic objects almost instantly. One of the greatest UV solution out there. My other personal favorites are of course, Headus UV, Bodypaint UV Editor and Modo's UV Tools.

Remember that all those software teams working to make things more easy to let you focus on your art instead of technical details. Which is great. 3D is not like as it is used to be. On late 80s it was just a dream to make an entire short movie or game all by yourself. Now it is getting more easy and fun everyday.

An Alternative Modeling Method: 3D Sculpting

Sculpting tools nearly removed the border between 3D and traditional art, which is in this case sculpting. If you have a powerful system - you can work with billions of polygons and sculpt your character or environment with using many great sculpting tools in the market. Zbrush, Mudbox, Sculptris (free), Blender's sculpting tools (free), Modo'd vector and poly sculpting tools are the most famous ones.

Next On Project Educate: Texture Mapping, Lighting And Rendering.
This article was for the Project Educate on deviantart

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