more important thing ... if you want
to get the realistic textures, then
you need to map something on channels
like diffuse, specular roll off, specular
color and others...
Sometimes when the objects are small
in picture and it doesn't take too
much attention then the simple fractal
mapped on the diffuse channel can
do very well. But, in situations where
you have the big object that takes
a lot of attention, it would be best
to paint the diffuse image to get
more detailed surface.
effect of using diffuse image is shown
in pictures below. The first picture
shows the simple shader network with
diffuse image mapped to it. The middle
image is the diffuse map that I've
used in this example. I've created
the image by mixing few textures from
3DTotal textures. Since the diffuse
is one dimensional value don't forget
that you need to paint grayscale map.
;) The difference between the shader
that uses single diffuse value and
the shader that uses image mapped
diffuse channel is showed in third
you can see, the surface material
looks more real and not so flat as
it was before. If you are creating
the metal surfaces then you will probably
want to do the mapping on other channels,
like specular color, specural roll
off, eccentricity and reflection.ack
to Maya. For the start I've created
a simple lambert shader, picked one
texture from 3Dtotal textures and
connected it to the color channel
of lambert shader. After that I went
to the attribute editor of the place2D
texture node of the image and set
the repeat UV to 2 in both direction.
As you can see, the shading network
(pic1) is as simple as it can be,
and the result of rendering is in
example of image file mapped
to the diffuse channel of lambert
shader; the image file used
as the diffuse map.
Difference of the shader that
doesn't have diffuse mapped
channel and the shader with
Lamber shader + image file on
last step but not the least is the
process of defining the lighting of
the scene. I've done this with great
help of Final Gather from mental ray.
If you do not know how to use final
gather then refer to my first tutorial
illumination. ;) After you read
it you will see that the light setup
is the same as in the scene from the
temple model. That means, only one
light was used, and the big sphere
was added to the scene which will
be used as the indirect illumination
first thing I did is that I've set
the main light. I had a choice of
few light types ... the point, spot
or directional light, all three will
fit as the sun light in this situation
but I have used the spot light because
it is very easy to position it ...
I can look through the spot light
and approximately know where my shadows
will be. ;) After few tests with global
illumination I decided to not go for
it, because in this particular situation
the final gather will do it's job
pretty good. If this would be the
scene where you need the light to
be bounced and bounced to get the
indirect illumination in the shadowed
areas, the global illumination will
be something you want. But this is
a different story...
direction of the spotlight when
looking through it. - Attributes
that I've used for the spotlight.
color of the main light was set to
something between yellow - orange
color, and I've used the Quadratic
Decay Rate. After I switched to Quadric
Decay Rate I boosted up the Intensity
value to 5000. The intensity value
is dependent on the overall scale
of the scene, but for my situation
the 5000 intensity value was the right
one. I also played a little bit with
Pneumbra Angle and Cone Angle to get
the non uniform distribution of the
light as you move out of center in
the sky light... no, it's not emitted
from the sky from the final picture.
It is emitted from the one big sphere
that surrounds the scene (pic1), and
it is hidden for anybody except final
gather. ;) This was easy to do, I
have just created one sphere, scale
it like in the image below so that
the scene is inside the sphere. Then
in attribute editor of the sphere
in the Render Stats section I have
turned off the Cast Shadow, Receive
Shadow and Primary Visibility. After
this, if the light will be placed
out of the sphere, it will not block
the light since it is not casting
shadows, and it will not be visible
in final render, but it will be visible
to renderer when it calculates final
gather. The last step I did was that
I assigned the shader to the sphere.
As the shader I tend to use the surface
shader. I have set the Out Color attribute
of surface shader to some dark color,
like dark brown (pic2). This will
produce the indirect illumination
that comes from the sphere and the
lighting will look pretty real. ;)
object used as the indirect
illumination source. - Shader
used for the indirect illumination
one tip. After you set the color and
intensity for the light and the color
of the sphere, many times you won't
get the right balance of these two
factors, the picture can be to bright
or to dark in shadowed areas, so you
would probably want to decrease the
one value and increase the other value.
For example in this image after the
first test render I decided to decrease
the intensity of the light and increase
a color of the sphere. Well, that's
it for lighting. Now the last step.
are times when I skip the postprocessing
part ... but since this time I wanted
to create the image in sepia tone,
and I wanted to put the transparent
frame around the picture, the postprocessing
step was the next logical move. ;)
There was also the background image
that was done in terragen modeler
and needed to be integrated in the
background of the original rendered
image. I use terragen very often when
I do a still image with realistic
hills and sky.
last step was created in photoshop.
I've used few layers as you can see
from the picture below. The background
layer was created in terragen ...
the camera in terragen was placed
so that it aprox. fits the camera
direction in the rendered image. Yes,
the color of the background has different
colors, but since the picture will
be in one tone, this wasn't the problem.
The second layer is the image layer,
rendered image from maya. The areas,
where the blue color is, are transparent,
they were only colored because I wanted
to show you where transparent area
is. If I hadn't turned off primary
visibility value of the sphere that
was used as indirect light source,
then this blue area would not be transparent....
now you know why I did that at the
lighting stage. The third layer is
the layer made with noise generator
and it's blend type was set to multiply.
This layer was used to make the picture
a little grainy. I've adjusted the
transparency of this layer so that
the grain is not visible too much.
The fourth layer has a frame, signature
and name of the picture ... nothing
special about it. The fifth layer
has constant color over it so that
it colorize's the layers below it.
The blending mode of this layer, as
you already know ;), is set to Color.
For the first and second layer I've
made a little curve corrections to
get a better contrast of the pic.
01 : background
hills and sky was made in terragen (terrain generator). Since this needs to be
in back it was placed in first layer.
02 : rendered image (normal)
layer is the rendered image. I've painted the blue color where the image is transparent
and the background (layer 1) will be visible.
03 : noise (multiply)
to add a little noise to the image I've created this layer and set the multiply
as the blending mode. If there is too much noise, modify the Opacity value.
04 : frame (normal)
tested the image with this frame over in and I liked it so it was used in original
05 : color (color)
last layer was used to colorize the image. It is a simple layer with constant
color over it with blending mode set to color.
this is it. Yes, the original image was flipped horizontally. ;)
this is the end my friends.. I hope this will be of any use to you. I didn't have
much time so I've explained only a few techniques used to create image. These
are not complex techniques, but it is something to start with.
good bye till next time...
This image was created using
a few of the hundreds of textures from the Total Texture CDs - very comprehensive
texture collections priced with the hobbyist in mind. To see more examples, download
samples and read full details follow