So, what is a prop. It is just like in the movies it is something to be added to a scene that represents a real world object. Just like in the movies it is important that it looks like the real world object and doesn't have to really work.
So, how do you build a prop? Well, I feel that a prop is based on three things. The first is a mesh that defines the shape of the 3D object. A mesh is just the shape, sort of like a statue. It has no colors or visual features on it. It only has geometry. The second major feature of a prop is the materials within the prop. The material is applied to a mesh. For example, if you are making a chair it would be the color, pattern and texture of the chair that is applied to the mesh or geometry. There are many other attributes of a material which I will talk about later. The third major feature of a prop from my perspective is physics. By physics, I am talking about how does the prop interact with other props or characters. Does it have a physical substance or can you pass through it? Does it have any motion associated with it, like a ceiling fan or a cymbal that has been hit?
How I build a prop is I start with the geometry. I generally use Blender or Second Life to create the Geometry. Basically the geometry or mesh is made up of polygons. For example a box has six, four sided polygons. The six sides of the box are called a face. A face in a box has four edges. These edges are shared with other faces. Each edge or line has two end points. These end points are called verticies. These verticies have an X, Y and Z position in 3D space. You move these vertices, edges or polygons and in that way shape a model into what you want it to look like. I use primitive shapes like boxes, planes, cylinders, spheres, etc that I combine/group/glue together to create even more complex shapes.
Blender is where I do the "heavy lifting" in terms of really creating the mesh geometry the way I want it to look. Because of Second Life's ease of use I will often start developing a basic 3D model in it and then capture the mesh using a SL2Blend program I built and finish it off in Blender. There are many books and tools available to build 3D models on the market. Blender is a little on the difficult side to use, but, is very powerful and best of all it is FREE!
Once I have shape I want I work on the materials. The tools I use depend on what I want to do with the material. For example, often I want to map an image onto the 3d geometry. I create the picture by either capturing an image or drawing it in a 2D graphics package. I use Print Shop Pro, Photo Shop or .Net Paint for most of my image work. Then I wrap this picture around the mesh using a technique called UV mapping. It is kind of hard to easily describe this process. Basically, what you do is take your 3D geometry and you flatten it out or unwrap the 3D object into a 2D image. Then you fit your picture over the top of it. The UV does not stand for Ultraviolet but instead it is U and V to describe the 2 axis of the map. In other words the image is 2D and therefore any pixel has a position that can be described in 2D space. Normally, we think of this as the X and Y axis. But, since we already are using the X, Y and Z points to describe the 3D mesh the axes are named U and V on the image. In other words, any UV point on the image has a corresponding X, Y, Z point in 3D space on the mesh. Clear as mud!
I utilize both Blender and a tool called UV Mapper to do this image mapping to a mesh. I apply the other properties associated with materials in Poser. These other properties include such things as colors, how the prop interacts with various types of light. The interaction of light with colors and images is a science on to itself. I have spent hours trying to get a better understanding of how a material looks in terms of the various types of light interaction that include the ambient, specular, reflective and diffusive properties of light with a surface and a color. How you set these properties is how you make a prop appear to be shiny, soft, silky, rough, glow, transparent, etc. I am fascinated by how to adjust these properties to change appearances. It has made me look at things in the real world in a whole new way.
Lastly is the physical aspects of the mesh. In side of Poser, you normally will animate each object or prop independently, so, you don't have to worry to much about how the objects will interact with each other. You just program that in by making sure that two objects that are solid don't pass through each other when you are animating them. In games where the objects are moving based on interactions with a user you have to program this differently. The technique I have used in gaming platforms is something called collision volumes (CV). This basically is done by identifying a space around an object that other objects cannot pass through. In general, in Poser the props I am building I am animating using their animation package which works a lot like "claymation" in the old Gumby cartoons. You just move the mesh one frame at a time and then control the timing and looping of these little movies you create. I will talk in great deal in other blogs about how I do this for various props and characters.
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