MASTER 3D POSTPRODUCTION
ADD DETAILS WITH TEXTURES
BLEND TEXTURES OF RUST, GRUNGE AND SCRATCHES TO BRING REALISMQUICK TIP
Keep a balanced eye and don’t over-edit your image. Especially in CGI post-production
where you have all these helpful rendered layers, you might be inclined to add and
blend layers too much. Always play with opacity, mask your layers and keep things as
natural-looking as possible.RENDER PASSES
This tutorial explains some techniques and the use of some render
passes in order to enhance your rendered image. These techniques,
though, might not work in the same way on every project and could
need some more tweaking. There are also some more render
passes that can help you in post-production, to add depth of field,
fog and other effects, that can also enhance your images.14
FIND THE SUITABLE TEXTURES
The image has some detail of extensively
used and grungy metal, but it lacks some logic in
its wear. To achieve that feeling, the best way is to
add some rust leaks, some edge wear and
scratches. To do this directly from 3D would
consume a lot of time. Besides that, adding this
sort of detail in Photoshop has the advantage that
it is not destructive and it is easy to control. A great
source for textures is CGTextures.com, a website
that offers a wide array of images, which can be
accessed for free. We downloaded a PNG decal of
rust leaking, which has enough variation and
information to be used all over the image.15
ADD RUST LEAKS
Before starting to add the leaks, you should
identify the best spots to add them: under objects, at
joints between objects, at the top part of some
objects. After placing the texture, you should use the
Wire Color pass, and select with the Magic Wand the
object you wish the texture to be applied to. Mask
the texture with this selection and paint with black
on the mask covering parts of the rust leaks. Repeat
this process until you cover all the places you think
there should be leaks.16
PREPARE THE TEXTURE
For this process, I downloaded another
texture from CGTextures.com. This image is
suitable because it contains both a grungy worn
edge and also some scratches. Now the image is
coloured and cannot be blended, so you should
desaturate the texture and add contrast to it. In
order to do this fast, while you have the texture
layer selected, press Cmd/Ctrl+Shift+U to
desaturate the image, and then Cmd/Ctrl+L to
bring up the Levels adjustment. Now pull the white
and black Input Levels sliders closer to the centre,
until you have quite a contrasted texture to use.17
ADD EDGE WEAR AND SCRATCHES
The texture is ready to be blended, but you should first
make a plan and think where this effect should appear: on the edges,
at some joints, and the scratched part on some plain surfaces that
lack detail. Place the texture where you think it suits best, and
choose Multiply as blending mode. Make a selection by using the
Magic Wand and the Wire, and add a layer mask to the texture layer.
Now you can paint with black on the mask and keep only what you
think is necessary to look good. Repeat the process and apply the
texture wherever it suits the purpose.18
SHARPEN AND SAVE
The image is almost finished, and it looks much better than the raw render.
Before saving, it is better to sharpen the image a bit, especially if the image is made for
print. Flatten the image, by going to Layers>Flatten Image, and then go to Filter>
Sharpen>Smart Sharpen and choose some small but effective values, like 100% for the
Amount and 1.5 for the Radius. Now the image is ready, so you only have to save your
image and enjoy your finished work!