Welcome everyone.

I am not the most prolific artist for the diagram. However, I have been using computers to draw pixel art for over 10 years. The following article will describe a step-by-step process that you can use to draw buildings for this wonderful diagram we have. It is by no means the only process one can use, but people looking for advice may be able to find some hints in here.

First a word on software. There are many different software packages one can use to draw diagrams. Many use MSPaint because it is easily accessible and fairly simple. I'm not too familiar with MSPaint, but I have used several similar programs. Some people use vector software like Illustrator or Freehand. I will not cover those in this article, this one will be about raster drawings. Personally, I use Paintshop Pro 7.0 for Windows, which is similar to Adobe Photoshop. However, Paintshop has all the features that I need, and it's much cheaper. Anything in this article can also be done in very similar fashion with Photoshop.

I will assume that you are reasonably proficient in the use of these programs. I don't have space or time to teach people how to use them, and there are people much more qualified to do so. Books and the web should help you out enough.

To illustrate the steps in the process we will be using an example. The example is the Yebisu Garden Place Tower in Tokyo, the first diagram I drew that I was quite proud of, and the first one drawn with the process outlined below.

Here we go!

Step 1 - Research

And you thought this was about drawing, right? Well, the first and most important thing is that you have sufficient source material for your diagram. This is difficult. I use Google as my search engine. I use both the standard search and the image search to build up a collection of as many pictures of the subject building as I can. Try to find pictures with a number of different angles and different lighting. The different angles will allow you to capture all the details possible (and their dimensions), and the different lighting will help you to understand the true colouring of the building.

Almost looks like a diagram already, right? As I said, I got really lucky. You're also lucky if you can see the building in person, because then you can take all the pictures you want, and you can see the details up close.

Now that you've got your source pictures, open them all up in Paintshop and start a new document. Time to start drawing!

Step 2 - Outline

The outline is probably the most time-consuming step, depending on how detailed the building is. In this step we will determine the dimensions of all the elements of the building, and draw an outline. We will not have the outline in the finished product, but it will guide us in the rest of the process.

Here is what the outline will look like:

The first step is to select a scale in which to work. Generally, my scale is either 3 or 4 pixels = 1 metre...in this example I used 3. The diagram is currently at 1 pixel / metre, but that could change, so you want to save a higher resolution version of your diagram. As well, drawing at a larger scale will allow more detail that will still look good when you scale down.

Create a new document slightly bigger than the dimensions of your building at your scale, with a white background. The reason for the white background is that the diagram itself will generally have a white background (depends on the user's desktop settings) so you want to avoid antialiasing artifacts with other colours. Next, create two new raster layers, one named "Colouring" (please use Canadian spelling :p ) and one named "Outline" in that order. Switch to the Outline layer and start drawing! You'll be using your paintbrush tool for this step, set to a 1 pixel brush size, 100% hardness and opacity. Remember, to draw a straight line, click once, hold down shift and click at the opposite end of the line. You can use the line tool if you want, but remember to make it not a vector and turn of antialiasing.

Try to measure the proportional size of different elements of the building. Start with what you know. If you know the building is 160 m high, and that a certain element is about 20% of the building height, then you know that it's about 32 m high, and you can then decide, based on your scale how many pixels high it is. Write down dimensions on a piece of paper. Count elements like windows and write down those counts too.

One of the first problems you'll probably run into is uneven division. You've got a segment that's 164 pixels tall, and you need to put 17 windows in. Each window should be 9.647 pixels tall. Well, that's impossible, and that's one disadvantage of pixel drawing. With vector tools you avoid this problem, but oh well. You'll have to make some windows 9 pixels tall, and some (about half in this case) 10 pixels tall. Try to spread them out, and don't worry too much. A difference of one pixel will be hardly noticeable once you scale your drawing.

Use cut and paste to replicate repetitive elements of your building. If you've got a lot to replicate, do it in multiples, ex: copy and paste 5 windows at a time. This will save huge amounts of time and reduce errors.

After a bunch of hard work you should have a complete outline. I know it seems silly, but this seems like a good place to mention this: save often!!! I usually save once a minute or so. You don't want to have to redo these tedious steps.

Step 3 - Colouring

This is one of the easiest steps. In this step, we will fill in the basic colours of the building, nothing fancy. Look at all your pictures and try and determine a best guess at the truest possible colours for the different elements. You can use the dropper tool for this. However, the dropper only gets one pixel's worth of colour, and our perception of colour in photographs comes from the average value of several pixels in close proximity. Look closely and you'll see every pixel is a different colour. It can be a difficult trial and error process to determine the right colour.

Here is what the colouring will look like:

As you can see, I made a few changes to the outline during this step, as I realized I had made some mistakes regarding the shape in some areas.

Switch to the Colouring layer and choose the selection tool. Make a selection defining the area you want to fill with colour, a window for instance. Switch to your flood fill tool and select your colour. You may want to set your match mode to none. This will allow you to fill the entire extent of your selection regardless of what was there before. Click inside the selection with the flood fill tool. The fill will be constrained to the selection. You should be able to see the colour behind the outline. If you want to see it better, change the properties of the Outline layer so that the opacity is less than 100%...especially if you drew the outline in black.

Continue to fill the building's colours out, and use the paintbrush tool to do small touchup work. You can add small details in this step, but don't do too much lighting or shading work. If there are entire sections of the building that are darker or lighter than others (those that are at an angle, for example) this is the appropriate step to select a darker or lighter colour for those sections and fill them in.

One note about colour selection in this section for glass. Give the glass a fairly dark colour. We'll be lightening it later. Glass is a real difficult subject when it comes to picking colour because it not only has a colour of its own (if it's tinted) but it also reflects colour, so its resultant colour is entirely dependent upon the angle of viewing, time of day and weather conditions. Try to find the colour that best indicates the natural colouring. In this example, I chose a dark green for the windows except for the lower ones, which are darker.

Once you're done this step, you can turn off your Outline layer's visibility using its properties page...you probably won't need it again.

Step 4 - Lighting and Shading

This step is probably the most fun and satisfying, as our building will now begin to jump out of the page. This step applies very differently to different types of buildings, so some may not benefit so much.

Here is what the building will look like after shading:

Our four main tools in this section will be the selection tool, the magic wand, the flood fill tool and the airbrush. The first thing we're going to do is shading. This will be done by applying a gradient fill to large areas. Use the magic wand to select large areas that will have similar shading. In this example, I selected everything that was not glass. To make this easier, select one section, and then use Selection -> Modify -> Select Similar to select areas of similar colour. Now use your flood fill tool, and set it to a gradient fill. Shading a building darker at the bottom and lighter at the top usually looks good, but be very subtle with the gradient. Don't make it too noticeable or it will look very tacky. In Paintshop 7, gradients can apply to opacity values as well, and this can help you to simply shade your building without losing the colour you already put down.

Next I worked on the glass. Use the magic wand to select all the glass and apply some gradient fills to create highlights on the glass in different places. I can't really give any advice on how to do this well...I just kind of played around with different opacity values, colours and gradient settings. With the glass still selected, and a light colour close to white chosen, switch to the airbrush and start adding random highlights to the glass. Make sure your opacity is low (<10%)so that the effects are fairly subtle and you can build them up gradually. You can also use dark colours with your airbrush to emphasize the highlights. You can also, if you want, find an image of clouds in the sky, and use it as a fill texture...but I hesitate to use this method.

Next step is shadows. Not all buildings need them very much, but this example really did. I chose to light the building from the top left, so the shadows will be on the right or bottom side of elements "sticking out" of the building. You want a hard edge where the shadow starts, gradually fading out. To do this, use the selection tool to select a rectangular area around where your shadow will be. Make sure the left (or top) edge of the selection is exactly where the shadow starts, but the right (or bottom) edge should be fairly far out. Select the airbrush and make its brush size fairly large (I think I used 15-20) but not too large. Keep the opacity low and select black or another very dark colour. Position your airbrush at the left / top edge and make straight strokes along the edge, gradually building up shadows. This will give you believable shadows in no time.

You can use the same process with a lighter colour for highlights if your building needs them. Just remember that the selection tools are extremely powerful as temporary masks when you're using the flood fill and airbrush tools.

Step 5 - Formatting for the Diagram

Paintshop makes this step easy for us! To reduce your diagram to a gif file appropriate for use in the diagram do the following (after saving).

• Layers -> Merge -> Merge all (Flatten)
• Image -> Resize
  • Use Pixel Size to set the correct height, 1 pixel = 1 metre. Set Resize Type to Smart Size.
• Colors -> Decrease Color Depth -> 256 Colors
  • I prefer to use Optimized Octree, Nearest color

Your image is now in 256 color indexed mode. One of those colours should be white. If you had white colours in your building, well, you shouldn't have. Nothing is pure white in this world...so you should make those colours slightly off-white. Use the dropper tool with your right mouse button to set the background colour to white.

• Colors -> Set Palette Transparency
  • Set transparency to background color. Use the Proof option to see if it looks right. Only areas outside of the building should show up as a grey checkerboard.
• File -> Save As
  • Select Compuserve Graphics Interchange Format and that's it!