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last update: 04.01.2008
 
A (first) introduction to architecture modeling with Blender
by Yorik van Havre
This tutorial is a general but step-by-step introduction to quick architecture modelling with Blender. It is focused primarily on architects who never really used Blender but know some 3D and who want to see how Blender can be used for their particular work. Blender users who are not used to architecture might find it useful too, although probably very simple. I will try to go slowly and explain everything, but there will be a couple of little things you will need to find out yourself... I am sure it is not hard and by searching a bit you'll quickly find your way. A good idea is to leave the blender manual open in another tab... And if you get really, really struck, just mail me...
This tutorial is about quick modelling, for building a well rendered image. It will not explore the details of precision modelling. It won't give you a correct model, that you could use to generate plans and sections. Instead, we'll try to find a balance between speed and correctness. Precision modelling takes much more care and time, so we'll treat that another time :) But I hope you'll be convinced, after reading, that we can obtain a pretty good balance, and while we may not be precise to the centimeter,still we should achieve a correct representation of our building.So I will try to mix a bit of all this and start with a true, real-life, everyday-experienced situation that you probably know too well:
 
1. THE STORY
This sympathetic person is your boss (no it is not Mario Botta, unless Mario Botta is your boss, in which case don't read this tutorial at the office). He has drawn a very quick project this morning, and he would like you to mount a quick perspective of it so he can impress the client and sell the project.
Of course it is now 9:00H in the morning and he wants it before 13:00H, because at that time he will have to go out for lunch with important people in an expensive restaurant in town and he wants to show them the image.

It is a little appartments building, 12 stories high, to be projected for some location in the city.
This is the thoroughly detailed piece of art your boss wants you to transform into an image capable of hypnotizing the client. Before you could even understand what is represented there, the boss went away to call one of his very important contacts.

Since there is not much information shown there, we'll have to invent a few things. This is quite common in 3D. The person who wants to see the project in 3D rarely has a complete idea of what he wants. Our boss, clearly, has no idea at all.

So don't be afraid to invent, develop, do what you want, as long as he can recognize his "design" at the end. Actually we are going to use this drawing as a base, but most of the things we'll have to invent when we do it.
 
Just as a note, if you are new to blender, you probably will need more than 4 hours to complete this tutorial, but I guarantee you that when you know blender well, doing this in 4 hours is perfectly possible, maybe even faster. I hope that at the end of this tutorial you'll believe me!
 
2. THE PREPARATIONS
First thing we are going to do is to scan the drawing. If the drawing is bigger than the scanner, reduce it with the photocopy machine so it fits into an A4 sheet, or any format your scanner can scan. We don't need much resolution. Scan it in greyscale (it makes smaller files) and any resolution will do. Let's scan it at 300 dpi, which is normally the default resolution on most scanners. It will be much more than what we need, but we might need the drawing at a good resolution later, so better scan it one time for all. We only have 4 hours. Save it in whatever format you like, but jpg (with at least 85% quality) is fine.

Now we need to clean the scanned image. Open your image in your favorite image editing program. You don't have a favorite image editing program? Then download the GIMP, which is a very good open-source image manipulation software. In fact, the Gimp is Blender's best companion... Many image professionals will tell you that Gimp is not good enough for them, but it is perfect for architectural work, since we rarely need to work with absolute professional color precision.

How do we clean our drawing? We need to make it as clear as possible. So we will:
1: Open the image
2: Resize and crop the image to what we need 3: Increase the contrast between black things and white background using the color>levels tool 4: If necessary, finish the cleaning by hand, using the eraser. Just erase what's still very dirty
Now we already have a good base to work. Or at least, the best possible. Last thing to do, since we will use this image as a background in blender, is to make a smaller version, otherwise it will slow down your work much. Save a version of the image that fits more or less in a 1000x1000 pixels square. That should be enough for you to see the details and for blender to work fast.
 
3. THE BASE PLAN
Now our image is ready for use. Let's open blender: and locate, in the view menu, the background image panel:
That panel allows you to load an image and put it in the background of your view. There are several interesting options here, play a bit with the Blend value until it all looks comfortable. Next, a very important thing: We will put that image to scale. For that, obviously, we need to KNOW what size the building is. Well, the boss didn't tell us... We'll have to guess. There are a couple of things we can see:
  • The elevator is easy to see, at the center of the building. It has stairs around it. An elevator is a square of more or less 2.00m x 2.00m. These types of common stairs usually have a width between 1.00m and 2.00m, let's decide 1.50m.
  • There are two rooms on each side of the elevator/stairs box. Usually a room has between 9.00m▓ and 12.00m▓, let's shoot for 11m▓. The proportion of those rooms looks something like 3/4, so that will give us a little bit less than 3.00m for the width. (3m x 4m would give us 12m▓).
  • We can now estimate the total width of that building, it would be something like 3m + 3m + 1.50m + 2.00m + 1.50m + 3m + 3m =17m. Let's put it at 18m, because we know that during a project development areas often tend to reduce, because we architects forget a lot of things when we begin a project... That 1m more is our little reserve for later.
Now place yourself in top view (Numpad 7 key), in case you are not. Remember to press that key again whenever you want to get back to top view.
Now things are easy. We have a 18m-wide building. So let's prepare it. Select the default blender cube and erase it. Instead, add a plane (SPACE key menu, add mesh, plane). Switch to wireframe dislplay (Z key) so we can see through it, and get out of edit mode (TAB key). Then:
1. Scale the plane (S key) so that its width occupies 18 grid units 2. Increase values in the Background image panel so that the image comes to fit in the 18 units width. We can now see the building mesures about 17m in length...
In this example I chose to work in meters, so I decided that one blender grid unit equals one meter. I could have chosen something else, of course. I can also do all the work in meters, when it is still early in the design process, and scale it by 100 to work in centimeters later.

In all this exercise, we won't worry much about precision (I have vague plans to treat that in another tutorial), since obviously our boss is not worried about having a precise result. So we will use much our eye and our sense of proportion to determine the size of things. What is important, whenever you work without precision in architecture, is to keep in mind what is important.
For example: You see in the second image here above that it is difficult to know how to scale the image. The "walls" from the sketch occupy almost one meter! Should we scale it so our plane line becomes the exterior line of the wall? the center? the inner line? Look at the size of the rooms: We talked about 3m x 4m, and it is more or less there. So for me it is ok. "More or less" is a perfectly acceptable dimension in architecture, as long as you don't forget what is important: In this case, the people who will live there. Until the end of this exercise, always keep an eye on their spaces.

Now save your work (Menu File>Save). Don't forget to save often during this exercise. An accident can happen easily :)
 
4. THE STARTING PLATE
The most natural way to build architecture 3D models is to do the same way as they are built in real life: From the ground up. Of course for different types of building you could imagine different ways, but this is a very basic building: It will be like a big cake, with 12 levels and topping cream... So let's start from the ground. We will build first our typical floor unit, since it will be easy to duplicate it 12 times, and we will already have 80% of our building ready. So let's begin. Let's add a new plane object, that we will remodel until it becomes our base plan:
We will now begin to extend our base plane, moving the 4 first vertices to some correct position, then extruding and adding new vertices. First move (G key) the first four vertices (they are already selected) to a good position, for example a corner (first image). Next, deselect the 4 vertices (A key) and select only two, that we will extrude (second image):
Now the trick is to analyze your plan, and look at where you will need divisions. We will extrude (E key, then only edges) our vertices several times, so we create vertical lines where we will need them. Don't forget you can force the extrusion to go horizontal or vertical pressing X or Y key while extruding.
You should see now why we didn't extrude the whole length in only one big extrusion; we needed vertical divisions so we can extrude the balcony above. Of course, it would have been possible to extrude once, and then divide (CTRL+R) the face several times, we would have got exactly the same result. In Blender, as in any good program, there are always several ways to obtain the same result.
In case you begin to get confused with keyboard shortcuts, Blender has a quite impressive toolbox, which is accessed by pressing the SPACE bar, or keeping any mouse button pressed for a coulpe of seconds. All actions that we are performing in ths tutorial can be accessed via this toolbox. I recommend you to have a look at all that lies there. There is also a hotkeys reference chart.
 
Very likely you have noticed our building is perfectly symetrical. This is quite common in architecture, a bad and old habit that comes from antiquity and that architects use a lot, because it is easier and they are lazy ( though they may tell you any kind of other reasons). Well, for us it will be easier.

We will simply add a mirror modifier to our plan, and everything we'll do on the left side will be also done on the right side. We can do it anytime, but let's do it now, so we have the pleasure of seeing our work growing at double-speed... Switch your buttons window to Editing (F9 key) and locate the Modifiers tab. Then, add a mirror modifier:
If you switch back to solid mode (Z Key) now, you'll see that the work we have already done has been mirrored, around the original center of our object, the one it had at creation time, that is, the place where the cursor was when we created the plane. By luck, it is exactly where we want it.

Let's continue, and fill the rest of our plan the same way: select 2 (or more) vertices, extrude, stopping at every change in the geometry...
If you activated the "Do clipping" option of the mirror modifier, you'll notice that you can't extrude anything across the mirror line. Very useful feature. Now there are still some subtilities of our plan that we couldn't achieve with extrusion. For example the lower part, or the curved balconies... There we'll do a little more precise work, by cutting (CTRL+R) faces or edges, moving and extruding single vertices, and creating faces (F Key) between vertices:
Experiment a bit with all this, don't hesitate to delete some of your vertices in order to re-extrude faces correctly. You see here above that we can easily cut through faces (CTRL+R with at least 2 vertices selected) to create new vertex lines through our mesh. Do all the adjusments that are needed, and go out of edit mode (TAB key) and put in solid mode (Z key) to admire your work:
When you are done, you should have something like this. If you still have imperfections, enter edit mode again (TAB key) and work a bit more on it. Remember that you can extrude one single vertex (it will produce an edge) and make a face by selecting 3 or 4 vertices and pressing the F key. Try to reproduce the maximum of details, angles, holes, corners, because it will look better under the light. They will create more shadows. Don't hesitate to add a bit more here and there. Remember, our boss will have the impression he created it... Just don't add too much.  Just "interpret" his sketch the way you prefer. The best way to obtain good results is always to model things you like...

Also, have a look at all the modelling tools you have in the toolbox (SPACE key)... There is also a chapter in the manual describing it all.


5. THE MAIN VOLUME
Next thing, we'll put some volume to our plane. There, we'll need to be a bit smart: Remember how we extruded things in several steps, to create vertices where we needed them?  We'll do the same thing here. So we need to make a bit of planning: We need to know what heights we will extrude.

We will decide for a standard floor height: 3m. It could be less (or more if you build high-standard appartments), but let's stick with something easy to manage now. What elements will we need to model on our fašades? We'll have windows and balconies. That's about it. So let's see: balconies usually have about 1,10m. For windows, it depends: what kind of window? We'll certainly have big sliding windows that open to the balconies. They'll go from the floor to, let's say, 2.20m high. Remember that nobody will build anything based on our work. We don't need to be precise. We need to show more or less how it will be. I know that with 2.20m I'll be close to what it will be at the end, be it 2.10m or 2.40m... That's enough for now.

What else. We have probably smaller windows, for the kitchen or the rooms for example. We could make it from 1.10m to 2.20m, right? so we'll already have the horizontal lines, and all those things will be aligned, it will look better. Again, if later it'll be 1.20m instead of 1.10m, it doesn't matter for us now. Let's keep it simple.

I think that's about it. Maybe we'll have one of those small bathroom windows too? Let's put another line, let's say they have 60cm height and are aligned with our 2.20m line.. So their base would be at 1.60m.

So, resuming, we'll need a line at 1.10m, one at 1.60m, one at 2.20m and one at 3.00m, the final one. So let's do it: Go back to edit mode (TAB key), and select all your vertices (A key until all is selected). Extrude (E key) region, and type 1.10. enter. We just extruded all our plan to our first line. Do it again 3 times, using 0.50, 0.60, 0.80 distances. If by chance your extrusion went in the wrong direction, undo it (CTRL+Z) and force it to follow the Z axis (Z key) before entering the distance. This is because blender evaluates himself how to place the normals, which is not always the way we want them.
Great. Our first typical floor unit is already there.  We'll now need to sculpt the balconies and the windows. But first, same way as we did the mirror, we could already have a look at how it looks with the 12 floors...  Add another modifier: An Array modifier. Put its options on constant offset, z: 3m, count: 12 like below:
Well, not bad for a start, our building is here already. Now the boss can come, things will go faster. Ah, don't forget to save your work often, ok? Blender might crash some time, just like any other program...

Notice there is a small icon in the array modifier to switch it off when you are in edit mode. Very useful so you can continue to work on your typical floor, but when you'll go out of edit mode you'll see how it looks on the whole building. So let's begin to work on the back balcony. Select the vertices you don't  want, delete them, and extrude others to re-form the geometry. Don't forget you can force extrusions and movements in a certain direction (X, Y and Z keys) and also that you can extrude (or move) a certain distance simply by entering it while extruding. You can also recreate faces when you have their 4 vertices ready by selecting them and pressing the F key.
Another trick, you can work on vertices, edges or faces by switching the corresponding button in the header bar... Sometimes it is easier to work on vertices, sometimes faces, etc. You'll get used to it.
That will do it for now. Notice that I extruded a bit the windows inside, so it will give a little shadow when we'll render. For the rest, I didn't detail much the balcony, but most probably we'll do a view from the ground, so it doesn't matter much now. Let's create windows the same way in other places. Since the boss didn't draw any window, we are free to place them where we want, just like the ones here above. Try to have them fit in the lines we already have, so those lines will get reinforced, making our building look better, and it'll be easier for us too...
The living room's corner box wasn't very well drawn by the boss. This suggests he wanted "something" there but couldn't find an idea. This is where we can act, do something interesting, and he will naturally think he's the one who designed it... Fine for us... So let's do something. By lowering the 1.10m line and raising the 2.20m line, I made a kind of big glass aquarium there, so it will look like a giant glass column... And the apartment inside will have plenty of sun. You may choose to do something else, feel free :)
Let's finish it, make the front balcony, and put some last windows here and there, on the front and on the staircase, at the back.
Okay! I think our typical unit is more or less ready. By now you must have understood well how vertices, edges and faces behave, and how to switch from one to another. To remind you if you didn't find out, there are those small buttons in the 3d view header, in edit mode, that switch between vertices, edges and faces.

Let's get out of edit mode to see how it looks with all the floors:

 
6. THE FOOT AND THE HEAD
Alberti said it, a building is like a human body: It must have feet, a body and a head. Well, our body is already there, we need to provide a head and a foot. Let's begin with the head: What can we do up there? We'll have some stuff, elevator's machine room, maybe a couple of technical rooms... We could just use them to create a nice volume work. So let's create a new plane object, and lift it to the top, to begin to work.
Before we do that, it might be a good idea to rename our body object, so later, when we'll have many objects, it'll be easy to find it in objects lists... Locate where the object's name is in the edit buttons below, an OB:Plane.XXX button. Rename it to, let's say, Apartments.

Now let's invent something for the top: Add a new plane, add a mirror modifier to it, and place it above the 12 storeys:
Okay, that will do it for now. Later on we can refine it, but it is better to arrive quickly to a first "displayable" result. We don't have the whole day, remember. Let's switch to the foot. There it is more difficult, many famous architects have had many theories about treating the foot, over time. I will stick to a typical Moretti-style foot: simple, stone, smaller... What will we have on the ground floor? I don't care now. Let's just make it look nice, there will be many things to put in it later...
It is always a good idea, if you don't have any idea about what to do, to make a small sketch, that you can put as a background if you want, but in most of the cases it is not necessary, just the fact of drawing something on paper is enough to give you ideas on how you want your base to be. After that, you model much quicker because you alreay know what to achieve. When you get much used to Blender, you end up modelling directly, as-you-think... For now, let's sketch quickly something:
Fine. See that I raised the body and the head 3.00m higher, to give us space to work. Also remember that you have several view-related shortcuts (Numpad keys 1, 3 and 7) that can help you much to position things correctly. Again, we are not looking for absolute precision (This will come in another tutorial). What we want here is to give our building a quick good look. So that's it, we have now a complete building. Ugly, but complete.
 
7. THE CAMERA
Now things will go easier. We already know how to move objects. We have a camera in the scene already, if you didn't delete it. If you did, just add a new one with the SPACE menu, then add, camera. Select it and place it somewhere you like, and press the numpad 0 key to put the 3d view in camera view. If your camera is still selected, you can move it around, even in camera view. Useful shortcuts are G key (move), then X, Y, or Z to move in X, Y or Z directions, XX, YY or ZZ to move following camera's own original X, Y, and Z axis. You can also look at your scene the way you want, and then force the camera to adopt the current view (CTRL+ALT+Numpad 0). Now find a good view for our building...
You noticed our background sketch appears also in the camera view. This is of no importance, the 3d view background image is just for work, it doesn't appear in the renderings. But let's turn it off, because we won't need it anymore. Just go in the view menu, background image, then turn off the "use background image" button.

While we are at playing with cameras and view, let's configure the rendering options already, so we can start rendering. Switch the buttons window to Rendering options (F10 Key). Let's see what we might need here:
First we need to define the size of our rendered image, in pixels. This is obviously set by the SizeX and SizeY buttons, on the Format panel. You can specify already a big format, for final output, since blender allows us to do smaller renderings quickly by using the 100%, 75%, 50% and 25% buttons without having to change the image size parameters. Let's put here SizeX:2000 and SizeY:1500, which will give us an image of 3 Megapixels, which is good enough for an A4-size printing. Let's also press the 25% button. We'll do full-size renderings only at the end. Another important thing, the OSA button, which controls Anti-aliasing. It can be turned on and off, and has 4 quality levels, 5,8, 11 and 16. Let's turn it on now and leave it on 5, so we'll have basic anti-aliasing.

Now.. There is one big nice button labeled "Render" that is just waiting for us... If you were able to control yourself until now and didn't push it yet, well... you may now kiss the bride... click it!
That's it... not exactly stunning, we could say. If you deleted the default light or if by bad luck it is inside the building, you might not see any light at all, your building is then completely black. This is just normal. No good illumination, no good image. Let's, then, solve that quickly, because the time passes and it's getting late.
 
8. THE LIGHTS
Lighting is by far the most important factor for creating good-looking images. There are many ways and tools to light a scene, and be able to do it very well is something that takes much time to learn. Well, since we just have a bit more than one hour, we'll have to find some quick way. I'll show you here two quick tricks: a sun & sky setup, and a traditional photography studio setup. Both are very quick to mount and give you fairly basic-but-good result. Gentlemen, to the left, the sun & sky method, to the right, the photo studio method:
The sun & sky
Here you simply use two type of blender lights: a sun and a hemi (skydome). The sun is a lamp that has the particularity of having all its rays parallels. This is the common way we represent the sun here on earth, since the sun is so far away that all its rays seem parallel to us. The hemi is a lamp that simulates a skydome, or light coming from all directions. The combination of both recreates more or less what we have in real life. Insert those two lamps (SPACE menu > add > lamp > sun and add > lamp > hemi) and place them more or less this way:
The classical photography studio setup
This is a quick lighting setup that you will encounter in many 3D tutorials on the net. It is the classical lights disposition used by studio photographs. It is also what they teach you when you learn traditional drawing. It is very useful in 3D, I always start with it when I still have no idea about what kind of lighting I want, or, like now, when I don't have time to try other things.
That setup is made of three lights disposed like in the scheme below:
Note that the sun has also been rotated to point to the building. That's the direction of the sun's rays. Our shadows will depend on it.

Switch your buttons window to "materials" by pressing F5 and give the sun a sun color, and the sky a sky color, like in the images below. And since we want our sun to project shadows, turn on the "ray shadows" button in the sun material panel. The hemi light cannot project shadows, unfortunately.
The first one, the sunlight, has to be strong to produce sharp shadows. Let's make a spotlight (or a sun light if you prefer), yellowish color, with ray shadows turned on. Refer to the sun & sky method here besides.
The second one, the skylight, has to be blueish, weaker, and project soft, blurred shadows. Create a spotlight, orient it correctly and turn buffer shadows on. Put bias setting to the minimum possible, and raise the soft value to blur your shadow. Also set clipsta and clipend values to auto.
Then, render again. and if you are not satisfied, play a bit with the color and energy parameters of your two lamps. The position of the sun is also important to make shadows bigger or smaller. At the end, you shoud arrive to a result like this one: The third one, the backlight, can be a simple lamp, with a medium grey color. Disable its shadow, since shadow is expensive, we won't use where not necessary. Also, disabling the shadows permit the light to cross the building and reach the front parts.
At the end, you must arrive to a setup similar to this one:
Your result can be a bit different, you can see that I kept the sky intensity quite dark, because I like to have strong, dark shadows, like if there was a very hot sun shining. You may want to do something else, but always try to imagine a real situation, it will be much easier. Of course yours can be a bit different. Try to vary the height of the three lamps so their focus areas are not all at the same height. When done, render it, and you should obtain something like that:
You can see that both methods give about the same lighting, but the right one gives us much more control. Since the blue light is a real lamp, not a simulation, we can place it where we want and it since it projects shadows, we can have nice shadow effects on the blue side, and we see the geometry much better. Also, notice how the down side of the balconies get illuminated too.

You begin to get the trick, don't you?  More lights, more control. But be careful with that, too many lights make it VERY difficult to control. Try to stay with 3 lights, it's enough for 99% of exterior scenes. When you play with light settings, try to be very systematic: Modify one setting, render, modify other setting, render again. Render again every time you change one setting. That way you won't loose yourself. It takes a bit of manipulating to achieve a good image. With time, you'll get used to it, and you won't need to render that often.

Also, see now why we set up the camera before the lights? The position of lights, in the right case, depends on the camera. When you make several views of a building, you usually need a different lights setup for each. In Blender, you do that creating several scenes.

Last thing, don't forget to take the good habit of giving a name to all your lights (just like our other objects), so you can recognize them easily later.
 
9. THE MATERIALS
Well, well, we are almost there, don't you think? Now let's see what materials we'll need:

1. A base wall material, let's make some sort of colored cement.
2. Another wall material for special elements, like balconies, etc... Why not try a wood?
3. A glass

Of course here the boss didn't specify anything, we'll have to shoot in the dark. Well, you must have a small idea of his color tastes, don't you? Bosses use to have well defined color tastes... I would suggest making the base wall material in his favorite color. The material 2 should be a color that goes well with the first one. There is a site that quickly proposes you matching colors for the one you pick. Okay, we have our colors, let's build the first one. Switch your buttons window to Materials (F5). Select your appartments, and click the "Add new" material button. A fresh new material gets created:
Let's now fill this material with what we want. Play a bit with the three colors values, and everything you find in the Shaders panel, so it looks more or less, basically like what you want. I'll pick a light orange tone, and put "spec" value to 0 because I don't want any "glow" (it's a cement... cements don't glow. Yes I know in Quake they do but we try to stay on earth). When you are more or less satisfied, let's choose a texture image for it, for example on cgtextures. Choose an image, and download it to some place on your computer. Then, in the Texture panel of our material, let's click "Add new" to, well, add a new texture... Then, switch your buttons window to Textures (F6).
The texture I choosed... And the texture settings. Rename your new texture, Choose the "image" type, and click the "load" button to take it from where you saved it. That's it, you have a new texture, made of your image.
Now switch back to material settings (F5). Notice that we have a pile of texture slots there, so we can add more later. Since we created our cement texture, the texture panel gained two more tabs: a "Map Input", for specifying how the texture will be placed, and a "Map To" for specifying what the texture will affect. Let's configure that for our cement:
These are the settings I choosed in the Map Input and MapTo tabs. They are exlained below. Feel free to experiment with all those
In "Map to" I activated the "col" button, so our texture will affect the diffuse color, and "nor" which will affect the bump value (in Blender it is called Normal). I reduced the "col" value (which, obviously, controls how much the texture will affect the color) much. Why so much? Well, the image we took on cgtextures.com is not seamless. That means, its left side doesn't match with the right side. So, when our image will be tiled on the building, the seams between the images will be very visible. Lowering the color value is a quick way to hide a bit those seams. If we had more time we could also add another texture on top of it. The "Nor" value, which controls the normal effect, will stay at 0.50 for now.

In "Map Input" I activated "Glob" and "Cube" buttons. Glob sets the texture scale to "Global", meaning "one texture image fits in one global blender unit". In our case, one meter. The default "Orco" means "one texture image fits in one object", which would obviously give you different mapping sizes on different object sizes. Since we make "real world" materials, we use the "glob" one most of the time. We want our material look exactly the same on big and small objects.
The "cube" button tells Blender to apply our texture as if it was projected from a cube, instead of "flat" from above. This what we use in 99% of the cases in architecture.

Note the size parameters set to 20% (0.20). How does that work? Remember "one image fits in one meter", right? Now, 20% of an image fits in one meter. In other words, one image fits in 5 meters. Our cement texture now is 5mx5m large.

Now our cement is ready, let's test it. Remember we selected our building before making the material? Well, that means this material is asigned to it already. So, let's render:
Isn't that great already? We can see small problems, on the darker side we can see vertical repetition: 3 same "clouds" one above the other. We could solve that quickly by making the image twice bigger. Set the size settings to 0.10. That should do the trick.  We could also apply another texture on top of it, with different size settings, etc... Texture repetitions are always a problem with image texturing, and we must always find tricks to make it disappear. Another solution is to use procedural textures, (all of blender's texture types other than "image"), which don't repeat patterns.

Now let's make the second material. Click " Add new" besides the material name. This will create a copy of our cement. 
Here I downloaded a wood texture, then did "add new" too in the texture panel (our new material was still using the cement texture), and assigned the new downloaded texture to it. I left all parameters like they were.

Don't forget to give proper names to your materials and textures. You certainly understood now that materials and textures are two different things and materials can use whatever texture they want, so be sure to have clear names so you know what is what.

Now let's create our third material, the glass. Create it,  remove its texture and give it a strong and narrow glow (the "spec" values in the Shader panel), like below:
Note that we removed the texture ("clear" button besides its name) and activated the "Ray Mirror" button, and raised the "RayMir" value a bit. Hmm, there's not much mirror effect appearing on the rendering... That's mainly because there is nothing to reflect, the mirror is reflecting mirror that is reflecting the blue background... To look good, mirror materials must have something to reflect! This will happen right now.

Now we have our three materials, we must assign them to our objects. There are two ways to do that:

1. Split our objects by material, so each object receives one material
2. Assign several materials to objects, and then control which of those materials each face receives.

What way will we use? Well, you begin to know me, you know which one we'll choose, don't you? Number 2 of course. The reason is simple, we want to leave our objects the way we modelled them. We wouldn't like to explode our objects to smaller parts, would we? What if the boss, in a creative crisis, decides to change EVERYTHING? Better to keep our stuff clean and easy to modify. Let's go, then. Select the appartments (which are probably selected already), and switch your buttons window to Editing (F9). Our appartments will need cement, wood and glass. so, locate the "links and materials" panel and create 3 material slots by clicking "New" two times:
Here we gave our object 3 material slots. Then, switch to materials (F5) to fill each of these slots with a different material: See the same "3 Mat 3" button? browse through the three slots, and for each one assign a material. I put the glass in slot 1, the wood in slot 2 and the cement in slot 3, but the order doesn't matter.
Now our object has three materials, but we didn't tell which face receives which material. It is very easy to do. Go back to Editing buttons (F9) and then enter EditMode (TAB key). Put yourself in Face selection mode (small "triangle" button on the header). Then:

1. Select some faces that will receive a material, let's say cement.
2. In the editing buttons, panel "Link and materials" (like the image above), select the "cement" material slot (mine is 3)
3. Click "Assign"

Now do that again, with all visible faces, and then with the foot and the head of our building:
Don't worry, it is much faster than you would think. We cared to model with few faces, so there is not much work. You can switch off the modifiers in editmode, so it's easier to see what you are doing. The top part only has cement on it, so I created only one material slot for it.

When it's done, render again, and there it is, our fully-textured building is done! Now, if there is time, we can make some small adjustments. For example, I found my wood material a bit dark, so I whitened it a bit.

Now, we can relax, the boss can come, the building is there. But since we still have 15 minutes, let's put some background and foreground, because the glass still looks very bad. Remember, the glass only reflects what's around.
 
10. THE BACKGROUND AND THE FOREGROUND

The background
The perfect thing would be if we had a real photograph of the place. In this case, we don't have any. But since the boss told us where the building will be, we can go on google earth to have a look at how the surroundings are. No need to be very precise here, but we need to know if the surroundings are buildings, small houses, park, something like that.

Then, we need to make a background. The creative commons site has a search function for finding images that can be used freely in commercal works, as well as most of flickr photos. Just look for things like "city", "landscape", "cityscape" or your city name. You should find plenty. Once you have one, you may need to crop it a little bit in your image editor, switch your buttons window to World settings (F8). There, you'll see you can add a texture, exactly the same way we did with materials:
The texture I choosed... And the "World" settings. notice that "Paper" is turned on, and how you use the sizeX, Y, Z and dX, dY, dZ to crop the image to exacly what you need.
You'll need to render a couple of times to adjust the d and size parameters. When done, it looks like this.
Now notice how our glass improved, specially on the darker side. But on the front side it is still a bit uniform blue. We can do several things to that, a common trick being to add a landscape or sky texture to our glass material. In other words, create an "artificial" reflexion.

But since our image is still a bit naked, let's add some real foreground objects, they will serve the double purpose of being reflected and "frame" our composition.

The foreground
Here you can put all kind of objects: Trees, cars, people, streetlamps, etc... We can add this as 3D objects, if you search a bit on the net you'll find many free 3D objects to use, but the quickest way is to add images that have transparency in them. Traditionally 3D artists use to put this in an image editing program after the rendering, but it's much better to add them directly in blender, so you can change your model, render again, and no need to open another program again.

Those images with transparency (or alpha layer) are very hard to find on the net, but you can find a couple of them free to use on the blenderarchi site. You can also grab free samples from several texture vendors such as marlin or got3d.

So, let's take two trees from there and place them in our scene. Since they are images, all we need to do is to make two big plates, or billboards, on the front of our scene, and make a new material for each, with our tree images as textures:
A couple of simple planes oriented to face the camera... The texture settings for our new materials, note the "use alpha" button pressed, this, of course, only works if our image has an alpha layer...
... And the material settings. Here we have the "A" value to 0 because we don't want the grey color to appear, "ZTransp" (basic transparency) turned on, "Traceable" and "Shadbuf" turned off because we don't want our trees to project shadows on the building, and the "Alpha" button in MapTo switched on because we want the alpha transparency from the texture to act on our material. I also turned on "Shadeless" because these tree images are already lightened, so we don't need our lights to alter that.
Well, I think that's it... Time to do a big scale rendering. Put it at 100% in the rendering (F10) buttons...
Note that I also made two more copies of our trees to mask a bit our entrance, since it is not very well defined.

Now it's about twelve, all we need to do is to print and give it to the boss. Probably, he will be back from the meeting with many changes to the building, but now, we know we'll be able to modify it easily.

Well, that's it, I hope you enjoyed. If something is still unclear or if you are struck somewhere, you can download the blend file of this tutorial, and if nothing helps, just mail me!

Cheers

Yorik - yorik.orgfree.com

with big help from Eon!

Ah, there is now a sequel to this tutorial, called Modeling architecture with precision in blender. Enjoy!