Full transcript
0:01some of you have been asking me for a
0:03series of tutorials for absolute
0:05beginners the first thing you need to
0:07understand is how light affects the
0:09appearance of form when you add light
0:11and Shadow to your drawing you can make
0:13it come to life by creating the illusion
0:16of form and depth you can make a
0:18flatline drawing looks like a real
0:21three-dimensional object it is because
0:24of light and the characteristics of
0:26light in the scene we're looking at
0:28light and how it illuminates Ates the
0:30objects in our
0:32environment light is the reason we see
0:34anything and the characteristics to the
0:36light can completely change the
0:38appearance of the objects it
0:41illuminates so let's understand how the
0:43light behaves for learning it the best
0:46way we going to start with simple shapes
0:49I'm going to example a sphere to explain
0:51about the different elements of light
0:54because this is a lot easier to
0:56understand than a complex form the first
0:58thing that is important to learn about
0:59life is the direction of the light here
1:02the light source is coming down from the
1:04top left in this example the light rays
1:08are completely parallel to each other
1:10this type of light source in nature can
1:13actually be considered the sun we
1:15actually have two main zones the light
1:18side which is facing the light source
1:20and the shadow side which is the part
1:22light can't reach when light shines on
1:25an object there is something called a
1:27Terminator The Edge where the form form
1:30transitions from light to Shadow it's
1:32located at the tangents between the
1:34light source and the form in other words
1:37just before the plane start to face away
1:40from the light from that point on the
1:42light does not penetrate the object in
1:45fact the border between these two areas
1:48is where the light becomes completely
1:50parallel to the edges and it's the
1:52beginning of the
1:54Terminator the edges can appear soft on
1:56matte surfaces like wooden object or
1:59Fair fabric stone or hard onshine
2:02surfaces such as a plastic Bowl glass or
2:05metal but these are for the pattern and
2:08texture lessons which need more
2:09explanation and we'll fully discuss
2:12about it later in another tutorial okay
2:15let's start by talking about the shadow
2:17side after the Terminator is the
2:20beginning of the Shadow shape Shadow
2:22shape generally includes two different
2:24parts which are two types of Shadows
2:27form Shadow and cast shadow form Shadow
2:30is a shadow caused by the plane turning
2:32away from the light source we usually
2:35see the form shadow on the object itself
2:38a cast Shadow appears when a form blocks
2:40the light from hitting another form in
2:42this case this sphere is blocking the
2:45light from reaching this part of the
2:46table you can find this shape by
2:49projecting the line from the light
2:51source to the Terminator of the first
2:54form which is the sphere and continuing
2:56those lines to reach the second form
2:59which is the ground or the table the
3:01cast Shadow can tell you where the light
3:03source is coming from all you have to do
3:06is Chase the edges against your object
3:09so let's see how the cast Shadow is
3:11formed what we have to do is to draw an
3:14imaginary line from the middle of the
3:16Terminator in the same direction of the
3:18light until it hits the table we
3:21considered a hypothetical ground for the
3:23sphere and we repeat these lines in the
3:26same direction and path in different
3:28parts of the Terminator
3:30and the only thing we have to do is to
3:32Simply connect these lines to each other
3:34to shape a
3:35curve along the Terminator sometimes you
3:38will see a core Shadow it's a darker
3:41plane that defines the edge of the
3:43Shadow and looks like a dark strip
3:45running along the boundary between the
3:46two sides the thickness and softness of
3:49the core Shadow can vary quite a bit it
3:52depends on the thickness of the form how
3:54sharp The Edge is between the planes of
3:57light and dark or the angle and position
3:59of of the reflecting light source
4:02sometimes you won't see the core Shadow
4:03at all Shadows are rarely completely
4:06black light bounces off objects in
4:09environments and it reflected back into
4:11the Shadows this is called reflected
4:14light or bouncing light in this case the
4:17light will bounce off the ground and
4:19into the shadow on the sphere causing
4:21the object to not be completely in the
4:23shadow or in other words light bounces
4:27off the table and illuminates the shadow
4:29side of of the sphere so we have direct
4:32light and reflected light so it happens
4:35only if there's something on the shadow
4:37side to reflect back enough light to
4:39create a visible difference in
4:41values there are so many things in the
4:44environment that light can reflect off
4:46of walls nearby objects tables or any
4:50surface the object is sitting on black
4:53surfaces absorb more light so in this
4:57example the core Shadow is no longer
4:59visible
5:00but white is highly reflective so as the
5:03ground gets lighter it reflects more
5:05light the same rule is for nearby
5:08objects lighter objects reflect more
5:11light and darker objects reflect less so
5:15as I mentioned light can reflect off of
5:17many things in the environment reflected
5:20light doesn't just affect form Shadows
5:23it also affects cast Shadows less light
5:26can bounce into this deep crevice for
5:29the sphere and table meet in fact this
5:31area is a tighter spot where the ball
5:34touches the table and so that area gets
5:37darker as it goes deeper this is called
5:40an occlusion Shadow let's move on to
5:43light side of the sphere immediately
5:45after the Terminator is the half tone or
5:48midtone midtones are the darkest values
5:51on this side of the sphere these are the
5:54planes of the form that are partially
5:56hit by the direct light where the edges
5:59start curving away from the light source
6:01these areas receive less and less light
6:04the more they angle away as the planes
6:07get closer and closer to facing the
6:09light they will get
6:11lighter and between these two ranges
6:14there are different values of light
6:17there's a point which is called the
6:19center light or core light which is the
6:21area facing the light directly a very
6:24simple rule that you need to pay
6:26attention to is the angle of the light
6:28and the angle of your object in relation
6:30to the light in this example this is the
6:33point that is specified here don't
6:36confuse the center light with highlight
6:39the difference between the two is that
6:41the center light is the plane facing the
6:43light source whereas the Highlight is a
6:46reflection of the light source this is
6:48the brightest point on an object the
6:50reflection will move depending on where
6:52the viewer is so the Highlight can
6:55change position depending on where
6:57you're
6:58standing the explanation I gave you in
7:01these few minutes are the most important
7:03informations you should know about light
7:06so start with simple shapes and then try
7:08on more complex shapes and there's
7:11actually no strange rule so far we said
7:14that we determine the direction of the
7:16light first and then the place where the
7:19light will be completely parallel and
7:22then we specify the Terminator and after
7:25that they form Shadow and then bouncing
7:27lights and then may specify the cast
7:29shadow on the ground with this simple
7:32method we can draw the shadows of an
7:34object and apply the same rules to more
7:36complex shapes my name is puny and I
7:39thank you for watching this tutorial bye
7:41till the next
7:53one