Creating Custom Props 4

Creating Prop Images From 3D Models

We believe it is easiest to create custom props in a 3D modeling program. There are a lot of them out there - some cheap, some deluxe. You might even find some shareware you can use. We at Maxis used a fancy program called 3D Studio Max, by Kinetix (very expensive). These directions are generalized to work with most rendering programs.

You will also need an image editing program, such as Microsoft Paint (installed with Windows), and there are other programs that will give you more power and flexibility. You will need this to take the images you have rendered in the modeling program and putting them into the format that BA Plus uses. You will also need to use Notepad, a simple text editor that also comes with Windows, for writing a configuration file for your custom prop.

You will probably want to use one of the many "prop template files" available for download on this site. These are pre-configured image files guaranteed to work properly in BA Plus. You will need to paste your rendered props into these template files to get the scale and alignments correct.

Rendering

We won't try to tell you how to build or texture your models. Just do what you like, and when you're ready, then try applying these factors to your rendering. These will guarantee that your prop's appearance will complement your buildings.

Lights

If you haven't noticed already, SimCity buildings are lit equally from two sides: the north-east and the south-west. We suggest setting up a series of "directional" lights in your scene (directional, meaning infinitely parallel light sources with no fall-off).

Have one pointing in each direction of the x-axis with an RGB color value of 255, 249, 232 (a warm color), and two more in opposite directions along the y-axis with an RGB value of 98, 98, 133 (a cool color). If your lights have a multiplier, set them to 1.30.Locate two more free-directional light sources, both with RGB 198,198,198 (multiplier 0.75) facing downward. Tilt one 30 degrees (from vertical) to one diagonal, and the other 30 degrees in the opposite direction.

If you can follow this, you will have set up a lighting scheme identical to the one used for SimCity 3000 buildings.

Camera

You will need four images of your sprite, and so you need to specify four camera points. You could set up four separate cameras, or one camera animation of four frames that moves to the four points. Be sure that your camera is using an orthographic or isometric projection (not perspective). If your renderer does not do

this, then you'll need to locate your camera very far from your object and use the highest possible zoom.

The cameras are diagonal to the lighting axes described above. The cameras should be pointing downward 30 degrees from horizontal.

Getting the scale and camera distance correct might take some trial and error. If you have an object that you expect to be the size of a single BA block, then it should render to be 32 pixels wide. Likewise, if it will be 8x8 blocks in size, then it should be 256 pixels wide (32 times 8 equals 256).

Action!

Finally, when you have the program render, you want to be sure that it does not anti-alias the image to the background; this will give unnatural "halo" effects when you use them in the BA. You'll probably want the background of the render to be colored RGB 255,0,255. Render to .bmp format. The total size of the rendered images does not matter, (as you'll be cropping and positioning them afterwards anyway) as long as the scale of the object is correct.

The BA Prop Format

BA Plus needs to have props formatted in very specific ways in order for them to work properly when placed on a BA model and rotated. Be sure to follow these specifications carefully to prepare your rendered images for BA Plus.

Choosing Image File Templates

Imagine your prop being packaged inside a large box comprised entirely of BA blocks. A bicycle, for instance, would probably fit inside one block (one block is approximately 2 meters cubed). A car might require a box 2 blocks wide, 3 blocks long, and 2 blocks tall: 2x3x2. A stairway might be 1 block wide, 2 blocks long, and 3 blocks tall: 1x2x3. Understanding the size of your prop will help you to pick the right prop template file.

[For technical reasons, the horizontal dimensions of these "boxes" must be odd numbers, so the 2x3x1 box for the car would have to go to a larger-sized box - 3x3x1. The stair would need to use a box that is 1x3x3.]

So, now you can choose the template that fits your prop (from the files downloadable here). Try opening one in an image editing program, say, the 1x3x3 template for the stair we've discussed. You will see the outlines of a 1x3x3 box are already drawn in this file. If you pasted an image of a stair in here, it would run from the top left to the bottom right. But what if you rotated the image 90 degrees? For long props like this, you will also have to use the symmetrical template file 3x1x3.

Aligning Your Prop Images

Now, you should use your image editing program to copy the rendered prop images into the template files. It will help if you copy only the prop and not the background, so that when you paste the image you can see the box outlines of the template.

After you've pasted the image in, move it around so that it fits cleanly within the box outline. Any parts that fall outside the box will not be shown in the BA. Be sure that it sits at the bottom of the box, as it would sit if it were in a real box - not too close to the front edges, but centered in the base of it. (You might need some practice to properly visualize this!)

Now, paint over the box outlines using the pink color - RGB 255,0,255. If you are working in layers, then flatten the image and save it as a .bmp file.

Repeat this for the three other images you rendered, saving each one with a different name (preferably numbered, such as "prop1.bmp, prop2.bmp, prop3.bmp, and prop4.bmp). If your object is something symmetrical, like a column, you may only have to include two images (since they would be identical to the last two).

A long stair alternating between 3x1x3 and 1x3x3 templates

Try very hard to imagine the object sitting in the same box, viewed from all four angles. If you are doing something long and narrow, like stairs, you'll need to use the second, symmetrical template file for every other image.

One final tip: If you are placing an image such as the car in the 3x3x1 template (as mentioned above), but it doesn't really need all that room, you might try aligning it off-center to one side - leaving those unneeded sections of the block remain empty. This will help if you want to place your props closer together.

Four rotations of a car within a 3x3x1 template

When you are finished creating and aligning your prop images, be sure to save them in the \SimCity 3000 Unlimited\Apps\BACustom\Props directory.

Composing The .met File

All props need a .met file (short for "metric file") to tell them how to be used by the BA. Each prop can have its own .met file, or you can put all .met data into one .met file. That's your choice. You just need to be sure that the .met file is in the same directory as your prop image files. Use a basic text editor such as Notepad to write your .met files.

Each line in the .met file is the instruction to apply to each prop image file. For example, let's say that prop1.bmp is a stair that used the 1x3x3 template and that you've also created prop2.bmp, prop3.bmp, and prop4.bmp for each of the rotations of that stair. The first line of your .met file should say this:
1,3,3:"prop1.bmp","prop2.bmp","prop3.bmp","prop4.bmp"

The first three numbers identify the template file used to create prop1.bmp - the first mentioned image file in the .met line. The three other image files on the line refer to the rotations of the first image file, in order of counter-clockwise rotation.

The second line of your .met file would read like this:

3,1,3:"prop2.bmp","prop3.bmp","prop4.bmp","prop1.bmp"

All the same ideas apply here as in the first line. The template file for prop2.bmp was 3x1x3 because the stairs were long and narrow and rotating 90 degrees would require the box to orient the other direction. Also, the sequence of rotations has shifted on, prop3.bmp the next rotation counter-clockwise after prop2.bmp, and so on. Starting to get it now? The entire .met file for this stair should read:

1,3,3:"prop1.bmp","prop2.bmp","prop3.bmp","prop4.bmp"

3,1,3:"prop2.bmp","prop3.bmp","prop4.bmp","prop1.bmp"

1,3,3:"prop3.bmp","prop4.bmp","prop1.bmp","prop2.bmp"

3,1,3:"prop4.bmp","prop1.bmp","prop2.bmp","prop3.bmp"

Save the .met file as any name you like, but with ".met" at the end. Be sure that this file and all the image files you have used are in the \SimCity 3000 Unlimited\Apps\BACustom\Props directory (or in a subdirectory within it). Restart the BA, go to Props mode and select "custom" in the pull down menu, and there you should see the fruits of your labor!

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