© 2002 Winston Mitchell
These templates are intended to give reasonable illumination for "single object" models. They are not intended for architectural subjects or interiors.
It can seem to be like the chicken and egg argument. When an image doesn't work, the question is: "What's wrong? The lighting? The materials? Or, (oh, please no) both?"
If you are inexperienced and struggling, the answer probably is "Both".
Here is my take on this: lighting first and materials second.
The reason: poor or no materials (just color from the color palette) and good lighting can produce very good images. Fantastic material and lousy lighting always produce lousy images.
Figure out lighting before worrying about materials. Photography is all about lighting and camera position. There is no control over materials (with the exception of highly controlled still-life images.)
Generally, good lighting should produce near-white highlights that hold some level of detail (with the exception of small specular hot spots) and shadows should be nearly black but not devoid of some detail.
If users don't figure out lighting first, determined ones may get good images after a lot of random tweaking; but the images will never reach their full potential. Worse, the process will never get easier.
To help you get started, there are downloads at the end of this article of the templates I use for Professional v6, v7, v8, v9, and v10. Most of the renders that I post on the forums are based on these templates.
The templates have five lights: three point sources, an ambient light, and a headlight. There is no magic in their position; I had to put them somewhere. They are arranged in a circle with the circle's center at World 0,0,0. Their height is 40% of the distance from the WorldPlane Origin as measured on the WorldPlane.
Note: All of the following position information is relative to the World Plane's origin. All angular information is about the World Plane's Z-axis and referenced to the World Plane's X-axis.
The second point light is the same as the first except that it is located 120° from the first and has Hue = 120 (slightly cyan colorcast).
The third point light is the same as the first except that it is located 240° from the first and has Hue = 200 (slightly magenta colorcast).
The above settings give useable images with most of the stock materials and pen colors. If anything, there may be too much light. Depending on the image content, turning off the ambient or the headlight usually brings things into balance. In any case, this lighting scheme produces plenty of front light and some back light for most viewing angles. The slight and differing colorcast of the point lights add some modeling cues without being overly obtrusive.
The above settings also produce hard, ray-traced shadows at all levels of detail. To change to mapped, soft shadows, you need to change the LightWorks specific settings of the point lights.
Of coarse, the values in the templates are just starting points. To change the settings of all three point sources at once, make the three point sources visible (keep the head and ambient lights invisible), select them, click "Properties" in the local menu, select the "LightWorks specific" section, and make your change.
If the lighting does not fit the model, select the three point lights and scale x and y with the Inspector Bar and set z with the Inspector Bar. Or, in a top view drag the lights where you want them (don't snap or they may end up on the workplane) and drag to a new height in the front, back, or one of the side views.
When using mapped shadows (Resolution more than zero), quality improves as the point lights approach the subject. This is because resolution is an angular setting. Moving the lights closer to the subject increases effective resolution without increasing rendering time. I usually start with the circle formed by the point lights having a diameter about twice the size of the subject's diameter (as viewed from the top).
Rather than immediately moving lights around and fiddling with intensities to get the effect you want, it may be instructive to spend a little time moving the camera around with the Examine tool. Slight changes in the point of view can produce dramatic changes in lighting effects with this setup.
My preference is for the Raytrace Full mode. Full works well but Raytrace Full adds anti-aliasing to shadows as well.
Pick the appropriate template and save it to TurboCAD's default template directory.
Template for v10
Template for v9
Template for v8
Template for v7
Template for v6.5
If you want to incorporate this lighting setup in an existing drawing or template, I suggest the following procedure:
To achieve high quality, snappy images with a full range of light values that hold details in the shadows as well as the highlights, you need to setup your monitor properly. Your efforts can be completely subverted if you don't do this. Unfortunately, this is also true for the monitor used to view the image and we can't do anything about that! Many lighting problems can be traced back to an improperly setup monitor.
If your monitor brightness and contrast are properly setup, you should be able to see a difference between any patch and its neighbor(s) in the step wedge below.
Here is how I setup mine.
After you do this a few times, you will find that it only takes a few moments and that it is well worth the trouble. For truly critical work, there are tools available on the web to fine tune monitor setup for brightness, contrast, color balance, and gamma.
If you have any of these, please post them in the appropriate forum in the TurboCAD User Forums.