by Jarek Dukat
This tutorial shows what you can do to make your objects look old and how to use light and volumetric effects to render a picture with a right mood.
Let's start with the objects: usually 3D objects look very clean and sharp. This can be ok for technical drawings, but not in an old house where everything has signs of time, objects are dirty and spoiled. Look at the picture below:
Walls near doors and windows are jagged and thanks to this simple trick they look much better. Creating such objects is very easy - you create straight line with many vertices, add noise modifier and then lathe. You can do this with a cylinder too. Then you just boolean/subtract such object from the wall corner and that's it.
Now the lights. In our scene there are no light sources inside the room, all lights are from outside: windows and door. Lights must cast shadows of course. To make the shadows softer increase the Smp Range to 6-10 or even more (this is just in the bottom of light's parameters). But the scene with only these two exterior lights will be completely black in areas where there is no light casted. This is why you have to add some ambient light to the scene. I usually use two directional lights one from left-bottom corner and second from right-top. I use overshot on for these ambient lights, this makes they have infinite radius, so they illuminate entire scene. Also in Environment menu there are two useful settings: Ambient and Tint. Be careful with using too bright environment ambient color because it flattens all other colors, lights and shadows in your scene. Moody lighting can't be 100% gray, it is always colorize in some way. Night scene in old house needs some cold color, ie. blue. Not nice saturated blue, but deadly pale blue. So add a little blue tint to all your lights (very little because when lights are too much blue all your scene will become blue, and we only want slight blue tint). You can also use the Tint color in Environment menu to add extra mood - also bright blue color and tint Level between 1 and 1.5. When all lights and tint colors are adjusted your scene should be dark, but with some visible details, like this:
Now the textures: old and dirty textures usually can't be made with one simple bitmap. They require some more advanced composition. Look at the wall below - it has many textures: wallpaper and bricks, water stains, cracks, and some extra dirty look - and it is only one object with one material.
Near the wall picture there is a Material/map
Navigator screenshot, it shows how the material has been build, i marked
maps with numbers so I can easier refer to them. Now a few words of
explanation: It is a Standard material, with bright gray diffuse color
and shininess = 0. Diffuse map is a Mix map (1). This lets you use two
different maps on the same object, and you can use a grayscale aplha
channel to mask (mix) both maps. This map contain three submaps: wallpaper
(2), bricks (3) and alpha channel map (4) - you can see the (4) map
on the picture near. As you see bricks and mask are 
just
bitmaps, but the wallpaper is more complex map - it is a Composite.
Mix lets you use two different textures in different areas of the object.
Composite map lets you put many (in this case three) maps in the same
are, one over another. First submap of the composite is on the bottom,
here on bottom we have the wallpaper texture, a bitmap (5). If you download
the sample scene and open the Material Editor on this map, go to the
Output parameters. You will see that the Output of this map is reduced
to 0.5. This means that only 50% of this map is visible, and 50% is
taken from map below it (in this case it is the material's diffuse color).
In this way you can easily tint the bitmap with material's color or
other map below it. Next map in the wallpaper composite is dirt map
(6) - it is a procedural noise map, it's output is also reduced to 0.4
so the bitmap is visible under it. The noise is black and white, it
adds some dirty look to the previous bitmap. And finally 
the
3rd map in the wallpaper composite: it is Mask (7). This map adds water
stains on the wall. Mask compositor lets you use any map with alpha
channel taken from other file, the alpha channel (mask) generates local
transparency of this map. On the picture near you can see the stains
mask. So the noise texture (8) generates dirty water stains and the
alpha channel (9) masks them to limited area on the wall. An finally
the cracks: it is just a bitmap used as bump map (10).
Floor, ceiling and door are standard textures from MAX Material Library. I also added an environment map simulating stars on the sky (it is a procedural noise map). The scene is almost ready:
The scene looks pretty nice already, but still the air inside the room is too clear. We have to add volumetric effects to simulate dust in the air. Go to Rendering/Environment and add Fog. Use dark, almost black blue (not too much saturated), near range 0%, far range about 50%. In camera settings define Environment Ranges Near = about half the room, and Far near the back wall. This will simulate effect of dusty air, where visibility in not 100% and things that are farther are less visible. Now add Volume Fog (create a box gizmo - Create/Helpers/Atmospheric Apparatus/BoxGizmo wider and longer than the room, but height only about 1/4 - 1/3 of the room), use maximum Soften Gizmo Edges and some fractal noise. This will simulate the dust hovering in the room. And finally Volume Light, and pick the lightsource shining from behind the window. Use rather low Density between about 1 and 2, and reduce Max Light to about 20-40% (to avoid too dense fog in the room and behind the window). Also the Volume Light should have some fractal noise to make it less uniform and solid.
A few more tips: Use camera with large FOV, bigger Field of View angle gives you more "dramatic" perspective, more overwhelming mood. If you want to add any light sources inside the room remember to use attenuation and soft shadows.
Now the scene is ready, your rendering should be similar to this one:
Click here to see an AVI
(1223k) or MPEG
(605k) of the room.
Big thanx to Lou for suggesting me the idea for this tutorial.
Sample
MAX 2 scene 99 KB
Note: following bitmaps are not included in the zip
file because they are standard bitmaps from 3D Studio MAX CD-ROM: blckcrak.jpg,
sunset90.jpg, burloak.jpg, oldwood.jpg
Jarek
Dukat
http://www.nautilus.com.pl/jarek