Nếu bạn làm cho đối tượng của bạn bây giờ, bạn sẽ nhận được một cái gì đó trông giống như hình 9 Tôi đã thiết lập ánh sáng trong cảnh để sử dụng radiosity tinh khiết với ánh sáng. Nếu bạn thấy rằng làm như vậy là quá chậm cho bạn | This page intentionally left blank. CWO14 Standard Projection Techniques Introduction to Standard Projections Figure 14-1 When working with images for texturing we have to define exactly how the image is to be placed projected onto the surface of the object as no program is so intelligent as to know exactly how to place an image onto a surface without some coordinates that tell it where to put the image and in what manner the image should be applied. Even in the following image we would need to tell LightWave how to project this texture straight onto the surface even though the placement may seem pretty straightforward and obvious. Defining these projections involves a process called mapping of which there are a number of different types. Mapping can be roughly divided into two main categories standard projections and UV mapping. Both offer a few different options for you to use and are suitable for different situations. To use a real-life analogy let s assume that you make a sculpture and then paint all the surface detail for that sculpture onto a piece of cloth. Okay I know it would be a bit odd to not just paint directly onto the surface but just bear with me here So you have your sculpture and you have your cloth and now you need to figure out a way of wrapping the cloth onto the sculpture so that it looks right. That is basically what mapping is. Do you stick the cloth straight onto the front of the sculpture or do you strategically arrange the cloth onto it 291 Chapter 14 Part 4 Figure 14-2 NOTE You only have to specify a projection type for images and for a few procedural textures as gradients and most procedurals do not require them due to the way that they are created. What makes mapping really challenging is that in any situation a number of different approaches could be applicable. The trick is to choose the best one and deciding on that requires a bit of planning and thought. To define the manner in which an image will be projected onto a surface you .
