by Scott "Icky" Rudi , game designer

Contents
Shape Building Philosophy
Shape Terms
Shape Damage Levels
Collisions
Shape Size and the Hit Box
Triangle Count and Textures
Don't Forget

Shape Building Philosophy

"Do not seek perfection in purity - find purity in perfection."
Zen Master Icky, 11/19/98

So, you think you can do better?

Congratulations! You've taken your first step to becoming a full-on shape builder! Below are several insights (ok, excuses) on why I made a lot of the objects as I did.

Shape building is very different than model building. In model building, you get to build incredible models using as many textures and faces as you darn well please. The only consideration is how the finished product looks. With some time and elbow-grease, any 3D modeler can come up with breath-taking scenes that tickle the mind... er, look good, that is (didn't mean to gross you out with mind tickling).

A shape builder has a completely different job. In addition to making a shape that looks good, he (or she) must consider other factors: how many faces (triangles) make up the shape, how many bitmaps, what does the shape do, are there moving parts, and so on...

The number of faces is the biggest challenge. This number needs to be kept as low as possible, or the simulation will slow down trying to draw all of them. Granted, the arrival of 3D accelerator cards lightens this load, but you still can't go crazy. My guidelines for building the vehicles in RB2 was around 20 faces/triangles to make the maximum detail undamaged shape. Think about it , 20 triangles to make an AATruck that's supposed to drive around the airfields. Nasty.

I remember once seeing a replica of the White House made entirely of toothpicks (yes, boyscouts ARE a wierd bunch). Thinking back, they must have used a few thousand of the little sticks of wood to make something that looked very real. Now, tell them to do the same thing with a few dozen and, well... you'd have a Swiss Army knife at your throat faster than you can say, "Be Prepared."

The shapes of Red Baron 2 / 3D were created with three things in mind - to look good, to not impede sim speed (framerate), and not overload texture memory. When editing the shapes, please try to keep those guidelines in mind. It might be easy to make an incredibly detailed and richly textured shape to replace the mundane ones you'd find in the game, but even the prettiest shape looks like crap at 5 frames per second...

In a nutshell - remember the K.I.S.S. rule: Keep It Simple, Stupid !<G>

Shape Terms

You may see certain terms in the lines below. Here's what they mean:

Vertex - basically a dot in space.

Edge - a line that connects two verticies.

Face - the surface area of a triangle.

Triangle - a combination of 3 verticies, 3 edges, and a face.

Part - a collection of triangles. A wheel would be a bunch of triangles that form a circle with depth.

Shape - a collection of parts. A car shape has wheel parts, a chassis part, and so on.

Object - a collection of shapes that contains all damage levels (if any). Some of the shapes may be hidden. A car object may have an undamaged shape, a damaged shape, and a destroyed shape all in one 3ds file.

Axis - All parts and shapes have an axis. The axis is the dead center of the shape, though it may be moved manually.

Normals - textures on a face are usually displayed in only one direction. A normal is the direction the texture will be displayed, unless the texture is designated as a 2-faced texture. Check out the bottom of the elevators on a Halberstadt DII to see what it looks like when you forget this...

Texture - a bitmap or flat color assinged to a face or group of faces.

Shape Damage Levels

MUCH simpler than the naming convention for the various shapes and details, the various damage levels of a shape are contained within the .3ds file itself.

When you load up a shape in your editor, you may see that some shapes are colored differently (if your editor has that capability). The undamaged (normal) state of a shape has blue parts, damaged is green, and destroyed is yellow. You may notice that the normal and damaged states are the same shape - this is because most of our damage is shown only via bitmaps. You, of course, may show damage any way you see fit!

Each part in the shape is named. A wheel part will be named, "Left Wheel" or whatever. Note that there is an extension after each part name. An extension of ".aa" means that the part is undamaged, ".ab" is damaged, and ".ac" is destroyed.

So, a jeep would have three left tires. "Leftwheel.aa", "Leftwheel.ab", and "Leftwheel.ac" to show the wheel in each of it's damage states.

Now, every part of the shape does NOT need damaged states. You could have a shape that graphically shows no damage by only having parts with ".aa" on them. You'll notice that most of the Low Detail level shapes have not damage states within the shape file.

HOWEVER, any part in the shape file that is damaged MUST have a corresponding undamaged part! This means that if you have a part called, "window.ac" - you better have a "window.ab" and "window.aa" in the shape file as well. Note that you may have a "window.aa" and a "window.ab" with no "window.ac" in the shape.

Just make sure that you have the preceeding letters of the alphabet in each shape.

One little trick I like to use is a single vertex named as a part. Single verticies (a vertex is usually part of a triangle) are not displayed because they don't actually take up any space - they are points in space (think back to your basic geometery). What this enables is "invisible parts" in a shape. For debris in a destroyed object, I create an actual debris shape to the side of the undamaged object. I name the debris shape, "debris.ac". Then I create two vertexes in the same space and name them, "debris.aa" and "debris.ab".

Most of my shapes have examples of this - just take a look in your shape editor...

Collisions

Collisions are a bad thing in the creation of a shape. Basically, a collision is when two parts of the same shape intersect one another.

For example, I built an Artillery Emplacement shape. The nature of the shape is that I have the gun surrounded by walls of sandbags. If I made the walls all one shape, then the gun shape would exist inside the walls shape. When the shape is drawn in the game, the program wouldn't know which shape should be drawn on top of the other since they exist in the same space. For this reason, I made each wall its own part.

A good way to check your work is to view your shapes in "box" mode, where the 3D editor displays your shapes in rectangular boxes. If any part of the boxes intersect, you have a collision problem.

There may be shapes where a little collision is unavoidable - like when wings connect to a fuselage. For this reason, the MCU utility comes with a "shrink" setting. This shrinks all parts in an object to their individual axiis - so that if just the edges of each part are intersecting, it will usually be enough to clear up any collisions. The object parts will not remain shrunk - it only does so long enough to clear up collisions and build a sorting tree (which part is drawn over another part).

Just remember to make sure that all parts exist in thier own space and do not intersect other parts too much.

Shape Size and Hit Boxes

There is nothing keeping you from taking a truck object in the game and creating a new object five times the size of the original. Some may be tempted to do this - instead of a church in the center of each city, how about a full-sized Notre-Dame?

You may be able to do this graphically - there is no size checker in the program to make sure that all the shapes in the game are the right scale. However, each shape in the game has a "hit box" drawn around it. A hit box is an invisible box or collection of boxes that can be shot by planes. When a bullet hits this invisible box, the program calculates damage, and so on.

The hit box will not change when you edit a shape. If you create a massive cathederal, it will still have the old small church hit box. You may find yourself shooting and flying through spires that may as well be made of smoke.

For that reason, try to keep your shapes the same basic size and shape of the original. Most vehicles have just one big hit box that is used for the whole shape. You could replace the Allied Large Tank in the game with a Russian T34 tank and probably get away with it. Both are roughly the same size and most won't notice the hit box being off in some places by a foot... On the other hand, the Factory shape has prominent smoke stacks - if you create a new shape that doesn't have these stacks, players may still hit them even though they aren't visible any more.

Experience and common sense will be your most valuable tool in this regard.

Another thing to keep in mind is the axis of the original object. Most object have their axis in the center bottom. As objects are placed in the world in relation to their axis, you could get yourself into trouble.

The large hangar's axis is like this, with its axis right in the middle of the object and right on the ground. If you edit the hangar and move its axis up from the ground, it will be drawn as if it had sunk into the ground up to where its axis has been moved to.

Also, the hit box is drawn in relation to the axis - if you move the axis, the hit box follows, no matter what the shape looks like.

Triangle Count and Textures

The number of triangles (aka faces, polygons, or polys) that make up the object is very important. Most of you will be tempted to create a really cool looking shape made up of hundreds or thousands of triangles. While this will indeed make much better shapes than you get with the boxed version of the game, it will also potentially slow the game down.

Remember that the computer has to draw the triangles - if you were to change the number of triangles in a city building from 12 to 60, you would increase the work that the computer has to do in drawing that shape by five times for EACH city building drawn on the screen. Little increases may eventually creep up on you - the expression, "Nickel and dime yourself into poverty" is as true with a triangle budget as with a normal money budget!

The textures that an object uses is also an issue. Most of the texture in the game are simple and small for two reasons - first, the smaller the texture, the quicker it is drawn. Every argument that can be used for conserving on triangles can be used for being conservative with textures. Sure, it would be nice for everything to have a 256 pixel mural slapped onto its side, but what  looks good at 5 fps? Secondly, what's used in the boxed version of the game is very near the limits on what a 4-megabyte 3D card can handle. If you were to increase the amount of texture memory (determined by bitmap size), you may have some angry Voodoo 1 users breathing down your neck.

Again, common sense and experience will be your best guide. This whole process is very much a "try it and see" cycle.

Don't Forget!

1. When you copy the new shapes to your \RedbaronII\Data\Simpatch folder (after running them through the MCU converter), you need to include the shape file (*.dts), the renamed material list file (*.dml), and all of the bitmaps used by the object. The game will crash if some and not all are copied in!

2. All new bitmaps must have thier correct RB palette loaded .The same rules for painting your plane are in effect for modifying  shapes.

3. Keep It Simple, Stupid! Some shapes may be tougher than others. Just like anything else - from cars to computers - as your shapes get more complex, more and more things can go wrong with them. Collisions, misspelled part names, mysterious "zero face normals" (don't ask), may have you pulling out your hair and/or wishing you could pull out ours.

4. What you edit may cause the game to crash. Try to edit one shape at a time so you know which shape is giving you trouble. If everything blows up in your face, you can always reinstall! Muahahaha!

5. This is something that was never promised, advertised, or anything. If it just won't work for you, too bad. Neither Dynamix nor *we* under any obligation to help or pull your fat out of the fire. Tech support ...well...doesn't exist for RB3D anymore , so no one at Sierra will have a clue what you are talking about regarding these shapes . Those who demand support will become *prefered targets* of  Flybert ,  Moritz  and friends ... he he

5a. Help each other out! The best aspect of "hacking" a game is the community environment it builds !:)