yoitisi
March 26th, 2008, 05:58 PM
This thread is for my mentees to post their work. If you're not one of my mentees but want to show your practice on these exercises or have questions, please check the Lurkers thread or general discussion thread.
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Assignment 8: Shadow construction
Alright time to move on to the next topic: shadows and shadow construction. This assignment will handle how to find out what the shadow of an object looks like and how to construct it in a quick and easy way.
The theory behind shadow construction is actually pretty simple and can be explained solely by the example below. Any shadow construction of a more complex form works in the same way, but of course there are tricks, shortcuts and pitfalls when it comes to drawing the shadows. I'll explain the most important ones further up in this assignment.
One note on beforehand, this assignment will deal with pretty basic settings. No difficult lighting schemes with multiple lights, nothing fancy on fading out and bounce light etc. For that sort of thing I suggest you do some study from life. This assignment deals with the very basis of shadow construction and how to get an effective shadow in a quick way.
333251
Once again, a step by step on how to get a nice and controlled shadow. We take a simple example to start with: a vertical pole (or stick or line - check the schematic version below the actual pole).
Step 1: Start out by drawing the actual stick or fencepole or whatever you like that looks somewhat like the example above.
Step 2: Now, introduce a lightsource. In this case, pick a spotlight (meaning, a single point in space that emits light in all directions). Notice that by drawing only the lightsource there are still a lot of possibilities left open on where the bulb actually is in respect to our fencepost.
Step 3: To determine where the lightbuld is, draw a vertical line to the ground and a line through where the vertical hits the ground and through the base of the fencepost. This can be anywhere you want, in this case I chose one that'll give a nice shadow on the ground. Play around with it if you like to find out what works and what doesn't. The line on the ground is called the 'projected light direction', as it shows on the floorplane the direction of your lighting. The vertical is to show how high the lightsource is in respect to your product.
Step 4: Now add the lightbeams that hit the top and bottom of the fencepost. The bottom one in this case isn't really necessary, but comes in handy if the post was actually floating.
Step 5: Where the lightbeam the hit the top of the post crosses the projected lightdirection is where the shadow ends. I added the thickness of the shadow already as the fencepost isn't a real one dimensional thing in space but has shape and thickness as well. For clarity you might want to check out the example below it.
For the rest of the examples in this assignment, keep the lower construction of the above example in mind. The next one uses it in basically the same way, only now it is two of those fenceposts connected with each other so the whole forms a plane (I made it a fence out of wooden planks :)).
333252
Step 1: As with the fencepost, start out with drawing the actual object first. Whatever you want to make of it, keep it a simple plane like the lower case above.
Step 2: Again, introduce a lightsource.
Step 3: As with the fencepost, determine where you want your lightsource to be. In this case I opted for it to be in the center front of the plane, but you might want to play around with this a bit more.
Step 4: Draw in the projected light direction and the lightbeams the pass trought the topcorners of the plane. Connect the two points you find in this way (the two points where the lightbeams cross the projected light direction).
Step 5: Marker in the shadow. As you see, I did make it fade out a bit the further away it is from the object. You can try to do this with markering it already, but since we haven't really gone into markering techniques yet you can also try it with either a white or a black pencil.
So far, we've only used point lights. While they give a decent shadow, they also have certain drawbacks that can be avoided. The most important drawback is the fact that the shadow is always a bit warped with respect to its origine, because the projected light direction diverges from its source. This both makes the shadow look exagarated and larger than needed (in the examples above the shadow is almost as big as the actual object). The problems I just mentioned can be countered somewhat by placing the lightsource further away from the object or by putting it higher from the ground, but the best solution is to use parellel lightbeams (meaning, placing the lightsource an infinite distance away - basically sunlight :))
333253
In the example above, the first one on the left is point light while the second on the right uses a light source with parallel light beams. As you can see, the second one looks less messy and doesn't distract as much from the actual object as the first one. You no longer need to determine a lightsource and where it exactly is in respect to the object, all you need to choose is the angle of the light and the direction of the projected light direction. Again, this decision is up to you.
In all of the following examples I'll be using the parallel light beams to construct the shadow, as it saves some work and marker inkt. Now that we've had simple sticks and planes, let's try a 3 dimensional shape. The cube is a nice subject for this :P
333254
Step 1: Nothing new, draw a cube to begin with. Note that I already played a bit with linewheight by making the lines which touch the ground a bit heavier.
Step 2: You can wait with this step until you marker the shadow as well, but as there's something to say about it already I put this step in second place. Why do we put shading on one side of the cube? The reason is that although you could opt for a light setting where each of the sides get an even amount of light, this doesn't help explain the shape. It's better to get as much difference in the different sides of an object as possible, as it will convey the shape stronger and makes it more readable for the viewer. Therefor, its best to have one side with shade. The little top view of the situation (image 2a) shows how the lighting works; the lower corner is closest to the eye while the light comes from 'over your shoulder').
Step 3: This step is basically four times the fencepost example: draw in the projected light direction for all four corners of the cube. Chose a direction the fits with the shading, in my example that is the light comes from the left.
Step 4: Now add the actual light direction on all the four corners of the top plane of the cube. It might be handy to mark where these lines cross the projected line direction as especially with complex objects it'll get messy real quick if you don't.
Step 5: Connect the dots and marker the shadow :)
Step 6: This is actually not a separate step, but an observation on the shadow you have drawn for the cube. If done well, you should see that the line AB of the shadow corresponds to the same vanishing point of line ab of the cube (they are parallel in perspective). The same goes for line BC of the shadow, which corresponds to the 2nd vanishing point of line cb of the cube. This is an important observation, as it allows you to draw the shadow much quicker: you don't even need to draw the actual light direction any more, you can go straight ahead and draw AB and CB by choosing their distance from the sides of the cube. Note that the projected light direction is the projection of the vertical ribs of the cube much like the fencepost example.
Okay, the next step is a floating cube. In essence, this isn't much different as you apply the same technique.
346733
Step 1: Start out with the cube again. By now you should be able to get it more or less cube-like :) Note that the cube in step 1 can be either floating, hanging from a wall or standing firmly on the ground. As long as there is no cast shadow, this will remain unclear.
Step 2: For the cube to float, we need to know how high it actually is from the ground. To do so, extend the vertical ribs downwards like in the example. You can chose whatever height you want, but the higher you let the cube float the further away the shadow on the floor will be.
Step 3: The next steps are quite similar to what I showed earlier: add the projected light direction and the real light direction. Only this time, use the points on the ground rather then the real corners of the cube.
Step 4: The result in this step is a shadow of the top of the cube. Still missing are the sides and bottom...
Step 5: Repeat step 3 for the bottom surface of the cube. Note that you can use the same lines for the projected light direction as you already used for the top. Now that you have constructed the shadow of the top and bottom surface, the only thing left is to connect the two to make it a shadow of a solid object.
Step 6: Marker the shadow. It might be usefull to compare the shadow of the earlier example with the cube firmly on the ground with this one.
Again, you end up with a lot of construction for a 'simple' shadow. Later on I'll put up some quick and dirty example that give you the same effect with less work ;)
The next example is about shadows on other objects. Having a nice open floor to put your object on is nice and easy, but often you'll have more complex shapes where the object has cast shadows not only on flat surfaces but also on vertical surfaces like walls.
346734
Basically, step 1 to 3 are nothing different than what is shown in the earlier examples. However, a wall is added so that the shadow will partly fall on the wall instead of only the floor. Step 3 ends with the shadowconstuction as if the two objects are separate drawings.
Step 4: Mark where the projected light direction hits the wall. This is where the shadow stops being on the ground and start to go up on the wall. Since we're dealing with a vertical stick, the shadow on the wall will logically be vertical too.
Step 5: To determine where the shadow ends on the wall you need the light direction as already drawn in step 3. Draw a vertical line from the mark you put down in the previous step and go up until you cross the light direction.
Step 6: Tada! There you have your cast shadow. I also added a shadow of the wall on the ground, though this isn't really necessary.
Sticks are easy, now we try the same with a cube.
346735
Note that I deliberately put the wall at an angle to the cube, so that the wall isn't parallel to the side of the cube. Feel free to try this yourself, but it's the easier version of the example above (also, I'm aware the wall seems slightly curved. Too lazy to fix it since it doesn't influence the construction for now :P)
Again, the first couple of steps are nothing new so I'll skip these.
Step 5: This is where it gets interesting. As you can see, I use the same technique as with the stick to find the top of shadow of the rib at the back of the cube on the wall.
Step 6 Connect the dots that make up the shadow and give it a marker tone and you're done.
The next examples are for you to try out. As you might have noticed, shadow construction is actually quite simple. However, it's easy to get lost in your own constructions.
346736
The four objects shown above all have their own nasty tricks to confuse you, which is why I will not do them for you. The theory as explained above still applies to all of them, so you should be able to construct the shadows by now.
1: A box on the wall. Make sure the shadow of it falls partly on the wall and on partly the ground. Making it an open box is optional.
2: A hollow box with a given light direction. You can vary the direction a bit, as long as all the dark sides of the box are at the back of the box.
3: Same story as 2, only with a different light direction.
4: Two objects, where the cast shadow of the first falls on the box behind it.
Now that you are able to construct a shadow for (at least) basic objects, it's time to make things a bit easier again. You might have noticed that to construct the shadow precisely, you need an aweful amount of lines and constructions that clutter up your drawing. As shown with the cube example, you don't really need all the construction lines. The following image shows a very useful trick that does not only apply for just this cube, but for most shadows you'll have to draw.
363279
The red line of the shadow has the same vanishing points as the corresponding red lines from the cube, the same counts for the green one. This is because they are both a projection of the 'horizontal' ribs of the cube. They also should have the same length as the lines they are the projection off (unless you're using a spotlight, but lets not go there for now). The only line that needs some thinking is line AB; this is the projected light direction as mentioned earlier. Choose this wise and your shadow stays simple :)
About that 'chosing your light wisely': here's another example. It shows three different light situations, each with their own uses and pitfalls.
363281
Situation 1: This one is often preferable above the other two. The reason is that by adding the shade on the right side of the object, you immediately make it more readable. At first glance the shape already reads like the tetris-block it is :) Note the little cast shadow behind the cube on top.
Situation 2: By shading the other side of the shape, it becomes a little less clear already. Instead of one solid shaded side, the shade is broken up in basically two squares. Again, note the cast shadow on the object itself. For some drawings this shading might be prefferable, but for most of the drawings you will make in this mentor course it's better to use situation 1, as this conveys more information.
Situation 3: Though a combination of 1 and 2 might sound cool, it often is the least useful of the three shown here. Though it is possible to differentiate the shade on the sides (left sides are a bit darker than the front) it doesn't read as well as situation 1 or even 2, as it tends to look like a solid block most of the times. Then again, when handled well this could work to give a drawing something more dramatic by using a backlight and rimlighting.
There are a couple more variations as you might guess, but the important point in most industrial design sketches is to quickly convey as shape/design without having to spend too much time on it. Also, when presenting tons of ideas at one time it is usefull if they all read quickly and easily :)
To conclude this assignment, below are some example of what shadows can do to your object. Note that all those shadows are 'guessed'; no construction was used, just the same knowledge as in the above exercises.
363280
1: Simple, you've already seen this above.
2: Now, by lifting the shape up a bit, suddenly the shadow is visibly at the front too. This really works well for small hand held products, but also for larger objects (check out some pictures for cars, they usually have a shadow like this underneath :P). Important to watch for is the fact that the shadow on both sides should be different in width: the shadow up front is much thinner than on the side. If you make those the same width, the drawing becomes dull.
3: Analyse this one for a bit. By simply twisting the swadow a bit, the object suddenly stands at an angle to the floor. Note that the shape of the shadow doesn't change, except that it becomes a bit shorter (or longer, depending on where you put the light).
4: This is a more dramatic shadow, much like it would look if you place a spot right above your object. I must admit I never use this one myself, as it is a bit too far out there, but some designers like it. Note that there's still only one side of the object that gets shade, so the form still reads easily. Also, by diffusing the corners of the shadow at the left and the right you can create a reflection in the shadow. We'll get to reflections later on.
That's it for this assignment, I'm working on the next one already.
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Assignment 8: Shadow construction
Alright time to move on to the next topic: shadows and shadow construction. This assignment will handle how to find out what the shadow of an object looks like and how to construct it in a quick and easy way.
The theory behind shadow construction is actually pretty simple and can be explained solely by the example below. Any shadow construction of a more complex form works in the same way, but of course there are tricks, shortcuts and pitfalls when it comes to drawing the shadows. I'll explain the most important ones further up in this assignment.
One note on beforehand, this assignment will deal with pretty basic settings. No difficult lighting schemes with multiple lights, nothing fancy on fading out and bounce light etc. For that sort of thing I suggest you do some study from life. This assignment deals with the very basis of shadow construction and how to get an effective shadow in a quick way.
333251
Once again, a step by step on how to get a nice and controlled shadow. We take a simple example to start with: a vertical pole (or stick or line - check the schematic version below the actual pole).
Step 1: Start out by drawing the actual stick or fencepole or whatever you like that looks somewhat like the example above.
Step 2: Now, introduce a lightsource. In this case, pick a spotlight (meaning, a single point in space that emits light in all directions). Notice that by drawing only the lightsource there are still a lot of possibilities left open on where the bulb actually is in respect to our fencepost.
Step 3: To determine where the lightbuld is, draw a vertical line to the ground and a line through where the vertical hits the ground and through the base of the fencepost. This can be anywhere you want, in this case I chose one that'll give a nice shadow on the ground. Play around with it if you like to find out what works and what doesn't. The line on the ground is called the 'projected light direction', as it shows on the floorplane the direction of your lighting. The vertical is to show how high the lightsource is in respect to your product.
Step 4: Now add the lightbeams that hit the top and bottom of the fencepost. The bottom one in this case isn't really necessary, but comes in handy if the post was actually floating.
Step 5: Where the lightbeam the hit the top of the post crosses the projected lightdirection is where the shadow ends. I added the thickness of the shadow already as the fencepost isn't a real one dimensional thing in space but has shape and thickness as well. For clarity you might want to check out the example below it.
For the rest of the examples in this assignment, keep the lower construction of the above example in mind. The next one uses it in basically the same way, only now it is two of those fenceposts connected with each other so the whole forms a plane (I made it a fence out of wooden planks :)).
333252
Step 1: As with the fencepost, start out with drawing the actual object first. Whatever you want to make of it, keep it a simple plane like the lower case above.
Step 2: Again, introduce a lightsource.
Step 3: As with the fencepost, determine where you want your lightsource to be. In this case I opted for it to be in the center front of the plane, but you might want to play around with this a bit more.
Step 4: Draw in the projected light direction and the lightbeams the pass trought the topcorners of the plane. Connect the two points you find in this way (the two points where the lightbeams cross the projected light direction).
Step 5: Marker in the shadow. As you see, I did make it fade out a bit the further away it is from the object. You can try to do this with markering it already, but since we haven't really gone into markering techniques yet you can also try it with either a white or a black pencil.
So far, we've only used point lights. While they give a decent shadow, they also have certain drawbacks that can be avoided. The most important drawback is the fact that the shadow is always a bit warped with respect to its origine, because the projected light direction diverges from its source. This both makes the shadow look exagarated and larger than needed (in the examples above the shadow is almost as big as the actual object). The problems I just mentioned can be countered somewhat by placing the lightsource further away from the object or by putting it higher from the ground, but the best solution is to use parellel lightbeams (meaning, placing the lightsource an infinite distance away - basically sunlight :))
333253
In the example above, the first one on the left is point light while the second on the right uses a light source with parallel light beams. As you can see, the second one looks less messy and doesn't distract as much from the actual object as the first one. You no longer need to determine a lightsource and where it exactly is in respect to the object, all you need to choose is the angle of the light and the direction of the projected light direction. Again, this decision is up to you.
In all of the following examples I'll be using the parallel light beams to construct the shadow, as it saves some work and marker inkt. Now that we've had simple sticks and planes, let's try a 3 dimensional shape. The cube is a nice subject for this :P
333254
Step 1: Nothing new, draw a cube to begin with. Note that I already played a bit with linewheight by making the lines which touch the ground a bit heavier.
Step 2: You can wait with this step until you marker the shadow as well, but as there's something to say about it already I put this step in second place. Why do we put shading on one side of the cube? The reason is that although you could opt for a light setting where each of the sides get an even amount of light, this doesn't help explain the shape. It's better to get as much difference in the different sides of an object as possible, as it will convey the shape stronger and makes it more readable for the viewer. Therefor, its best to have one side with shade. The little top view of the situation (image 2a) shows how the lighting works; the lower corner is closest to the eye while the light comes from 'over your shoulder').
Step 3: This step is basically four times the fencepost example: draw in the projected light direction for all four corners of the cube. Chose a direction the fits with the shading, in my example that is the light comes from the left.
Step 4: Now add the actual light direction on all the four corners of the top plane of the cube. It might be handy to mark where these lines cross the projected line direction as especially with complex objects it'll get messy real quick if you don't.
Step 5: Connect the dots and marker the shadow :)
Step 6: This is actually not a separate step, but an observation on the shadow you have drawn for the cube. If done well, you should see that the line AB of the shadow corresponds to the same vanishing point of line ab of the cube (they are parallel in perspective). The same goes for line BC of the shadow, which corresponds to the 2nd vanishing point of line cb of the cube. This is an important observation, as it allows you to draw the shadow much quicker: you don't even need to draw the actual light direction any more, you can go straight ahead and draw AB and CB by choosing their distance from the sides of the cube. Note that the projected light direction is the projection of the vertical ribs of the cube much like the fencepost example.
Okay, the next step is a floating cube. In essence, this isn't much different as you apply the same technique.
346733
Step 1: Start out with the cube again. By now you should be able to get it more or less cube-like :) Note that the cube in step 1 can be either floating, hanging from a wall or standing firmly on the ground. As long as there is no cast shadow, this will remain unclear.
Step 2: For the cube to float, we need to know how high it actually is from the ground. To do so, extend the vertical ribs downwards like in the example. You can chose whatever height you want, but the higher you let the cube float the further away the shadow on the floor will be.
Step 3: The next steps are quite similar to what I showed earlier: add the projected light direction and the real light direction. Only this time, use the points on the ground rather then the real corners of the cube.
Step 4: The result in this step is a shadow of the top of the cube. Still missing are the sides and bottom...
Step 5: Repeat step 3 for the bottom surface of the cube. Note that you can use the same lines for the projected light direction as you already used for the top. Now that you have constructed the shadow of the top and bottom surface, the only thing left is to connect the two to make it a shadow of a solid object.
Step 6: Marker the shadow. It might be usefull to compare the shadow of the earlier example with the cube firmly on the ground with this one.
Again, you end up with a lot of construction for a 'simple' shadow. Later on I'll put up some quick and dirty example that give you the same effect with less work ;)
The next example is about shadows on other objects. Having a nice open floor to put your object on is nice and easy, but often you'll have more complex shapes where the object has cast shadows not only on flat surfaces but also on vertical surfaces like walls.
346734
Basically, step 1 to 3 are nothing different than what is shown in the earlier examples. However, a wall is added so that the shadow will partly fall on the wall instead of only the floor. Step 3 ends with the shadowconstuction as if the two objects are separate drawings.
Step 4: Mark where the projected light direction hits the wall. This is where the shadow stops being on the ground and start to go up on the wall. Since we're dealing with a vertical stick, the shadow on the wall will logically be vertical too.
Step 5: To determine where the shadow ends on the wall you need the light direction as already drawn in step 3. Draw a vertical line from the mark you put down in the previous step and go up until you cross the light direction.
Step 6: Tada! There you have your cast shadow. I also added a shadow of the wall on the ground, though this isn't really necessary.
Sticks are easy, now we try the same with a cube.
346735
Note that I deliberately put the wall at an angle to the cube, so that the wall isn't parallel to the side of the cube. Feel free to try this yourself, but it's the easier version of the example above (also, I'm aware the wall seems slightly curved. Too lazy to fix it since it doesn't influence the construction for now :P)
Again, the first couple of steps are nothing new so I'll skip these.
Step 5: This is where it gets interesting. As you can see, I use the same technique as with the stick to find the top of shadow of the rib at the back of the cube on the wall.
Step 6 Connect the dots that make up the shadow and give it a marker tone and you're done.
The next examples are for you to try out. As you might have noticed, shadow construction is actually quite simple. However, it's easy to get lost in your own constructions.
346736
The four objects shown above all have their own nasty tricks to confuse you, which is why I will not do them for you. The theory as explained above still applies to all of them, so you should be able to construct the shadows by now.
1: A box on the wall. Make sure the shadow of it falls partly on the wall and on partly the ground. Making it an open box is optional.
2: A hollow box with a given light direction. You can vary the direction a bit, as long as all the dark sides of the box are at the back of the box.
3: Same story as 2, only with a different light direction.
4: Two objects, where the cast shadow of the first falls on the box behind it.
Now that you are able to construct a shadow for (at least) basic objects, it's time to make things a bit easier again. You might have noticed that to construct the shadow precisely, you need an aweful amount of lines and constructions that clutter up your drawing. As shown with the cube example, you don't really need all the construction lines. The following image shows a very useful trick that does not only apply for just this cube, but for most shadows you'll have to draw.
363279
The red line of the shadow has the same vanishing points as the corresponding red lines from the cube, the same counts for the green one. This is because they are both a projection of the 'horizontal' ribs of the cube. They also should have the same length as the lines they are the projection off (unless you're using a spotlight, but lets not go there for now). The only line that needs some thinking is line AB; this is the projected light direction as mentioned earlier. Choose this wise and your shadow stays simple :)
About that 'chosing your light wisely': here's another example. It shows three different light situations, each with their own uses and pitfalls.
363281
Situation 1: This one is often preferable above the other two. The reason is that by adding the shade on the right side of the object, you immediately make it more readable. At first glance the shape already reads like the tetris-block it is :) Note the little cast shadow behind the cube on top.
Situation 2: By shading the other side of the shape, it becomes a little less clear already. Instead of one solid shaded side, the shade is broken up in basically two squares. Again, note the cast shadow on the object itself. For some drawings this shading might be prefferable, but for most of the drawings you will make in this mentor course it's better to use situation 1, as this conveys more information.
Situation 3: Though a combination of 1 and 2 might sound cool, it often is the least useful of the three shown here. Though it is possible to differentiate the shade on the sides (left sides are a bit darker than the front) it doesn't read as well as situation 1 or even 2, as it tends to look like a solid block most of the times. Then again, when handled well this could work to give a drawing something more dramatic by using a backlight and rimlighting.
There are a couple more variations as you might guess, but the important point in most industrial design sketches is to quickly convey as shape/design without having to spend too much time on it. Also, when presenting tons of ideas at one time it is usefull if they all read quickly and easily :)
To conclude this assignment, below are some example of what shadows can do to your object. Note that all those shadows are 'guessed'; no construction was used, just the same knowledge as in the above exercises.
363280
1: Simple, you've already seen this above.
2: Now, by lifting the shape up a bit, suddenly the shadow is visibly at the front too. This really works well for small hand held products, but also for larger objects (check out some pictures for cars, they usually have a shadow like this underneath :P). Important to watch for is the fact that the shadow on both sides should be different in width: the shadow up front is much thinner than on the side. If you make those the same width, the drawing becomes dull.
3: Analyse this one for a bit. By simply twisting the swadow a bit, the object suddenly stands at an angle to the floor. Note that the shape of the shadow doesn't change, except that it becomes a bit shorter (or longer, depending on where you put the light).
4: This is a more dramatic shadow, much like it would look if you place a spot right above your object. I must admit I never use this one myself, as it is a bit too far out there, but some designers like it. Note that there's still only one side of the object that gets shade, so the form still reads easily. Also, by diffusing the corners of the shadow at the left and the right you can create a reflection in the shadow. We'll get to reflections later on.
That's it for this assignment, I'm working on the next one already.
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