Here we go:
CAST SHADOWS AS A TOOL:
I've wanted to bring up this topic for a while, because I love cast shadows, and with a good amount of basic knowledge about how they can be used effectively, it can really help push people's work. I'm no cast shadow expert, but I hope I can help some of you with this.
First and Foremost;
-Contrast
I know I am not alone in the high importance I put on contrast, as Danny and I have had a few conversations about it, and we both agree it's probably the most important thing in the 'big picture' of art and design. This is one thing that makes cast shadows such an unbelievably useful tool for us. So what Contrast does it provide?
-Value: This should be the most obvious. Cast shadows can collide with a lit surface and make a very beautiful value relationship. Keep in mind the brightness of your light source and your local value when deciding how dark the cast shadow should be. (left is using cast shadows, right is not)
-Edges: Cast shadows (naturally) are close to the object casting the shadow. This gives that 'shadow line' a very crisp edge (most of the time). It will soften the farther away the object is from the shadow. Alot of your edges within the shadow will be softer, so this will ofter 'contrast' in the edges. Look for opportunities to create 'lost' edges, but do it because it's correct, not cause it looks cool :P (this is a quck example. Notice the back edge of the rock- it's sharp, but the cast shadow has dissipated. Given the light, the shadow is incorrect, but let's ignore that :D)
-Temperature: Imagine you are on the highway at around 2 PM, and you come across an overpass. Look at the shadow of the overpass next to the un-shaded road. You have the blue light from the sky and the warm light from the sun. This creates a temperature contrast which increases interest and gives you a great opportunity to infuse color into your piece. (quick example from memory)
-Vertical/Horizontal: This is always a fun one- when deciding how to place elements into a piece, such as a large jutting rock or a massive support pillar, think also about how the cast shadow can be displayed to offer a contrast with that vertical object. It will be a mostly horizontal beam on your painting, but make sure that the 2 shapes aren't competing. To make it easy you can always aim for 1/3rd object area and 2/3rds shadow area, or vice-versa.
Secondly,
-Form and Space
Most of us in ID have had a taste of how 2d elements on a 3d plane can help you define the form of the shape without using guidelines or unnecessary section lines (remember viscom 1 final?) By using the cast shadow as a 2d shape, you can create alot of very easy, and also very believable graphic appeal to your painting.
-Shadow as a Graphic Shape: In Viscom 1 (or those who have seen Scott's 1st ID Foundations DVD), you easily recall the importance of drawing section lines so that you could keep track of your shape, and so that any viewers would clearly be able to discern the form you designed. A cast shadow can be used as a section line, and will re-enforce the shape of a vehicle, an animal, or architecture in your scene. Imagine a car parked halfway in the shadow of a tall apartment building, and halfway in the light. That edge is no different than the effect a cut line has. As long as you cast the shadow correctly, it will go a long way to help you define a somewhat ambiguous form.
-Shadow as an Indicator of Space 1: There are several instances you might run into where even though the perspective is right, even though everything is correct, a building, a pathway, or a vehicle might still not 'read' well- or it might read well, but it might just be boring. Adjusting your lighting to throw a cast shadow over it will not only help define it's location in relation to the space you have created, but will also re-enforce it's height, it's angle, and it's direction. (see above image as well)
-Shadow as and indicator of Space 2: This is one of my favorite things to do with cast shadows, and it will also help push the feeling of depth in your seen by 100x. Think of everything in the light as one shape, and everything in the shadow as another. SAy you have a tree casting a shadow on a patch of grass. Instead of making the shadow flat, you will have light bits of grass "on top of" the shadow shape, and similarly, where the top of that shadow meets the light, you will have shadow shapes of grass "on top" of the light! This also indicated where the tree is located, and can be used with characters, vehicles, or random miscellanea within your scene. (look at the values of the cylinders and how they pop against their background/environment)
-Shadow as indicator of Space 3: Scale can be a very hard thing to "get feeling right". Sometimes something just isn't reading quite as 'epic' as you'd like, but you've added the atmosphere, you've added the 2 pixel wide windows and hand railings- you've even found a clever way of putting in a sign that says "big ass object- 9 million miles away"- but it still ain't cuttin it. Look for a cast shadow. Check your light source, make sure the shadow is as big and elongated as it should be, and make sure if there are sky scrapers in the scene, that you do the "layering" trick with them previously mentioned. This will set your object even farther back, and make it look even taller at the same time. (no visual aide... hope people get my meaning with this one)
-Shadow is implication/assumption: If you feel like your ground plane is not well indicated enough, especially in the foreground, A very, very simply solution is to drop a shadow right across the foreground. You don't even need to indicate the object casting the shadow (although you could, such as the rim of a cave). There is actually a word in french to describe this, as alot of classic painters used this as well.
Sorry for being so long winded, but I hope you learned something! Make sure you read the comments, as I hope other people can weigh in on this subject as well (I will edit the post to put it up, with credits to those that contribute etc.)
-J
