Creation of a Complex Shape

7/30/2019 Creation of a Complex Shape

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Creation of Complex Shape (Trains, Carriages and such)

TextureThe usual size of main engine texture is a 512 by 512 pixel texture, however not all

graphics cards support this size of texture so a 256 by 256 pixel texture is sometimes

used. Although this is difficult to ascertain whether it is necessary or not, most

graphics cards will reduce a 512 by 512 pixel texture to a 256 by 256 pixel texture if

they cannot handle it.

There is no predetermined way in which to build a texture for a main shape or any

other shape but there are a few tips that can aid to a creation of a good texture.

Kuju Entertainment Ltd used a lot of photo texture resource for the creation of

textures on Microsoft Train Simulator, which aided in the creation of a realistic

environment.

The pixel ratio must remain constant as in 512 x 512 pixels, 256 x 256 pixels, 128 x

128 pixels, 64 x 64 pixels or 32 x 32 pixels.

To give an example of a complex shape using a complex texture, take the following:

The Acela shape above uses two 512 x 512 pixel textures and one 64 x 64 texture.

These are colour coded for your reference and do not represent the real texture. The

top 512 x 512 pixel texture is used to map the sides, front, back and logos of theengine and contains no transparency. The bottom 512 x 512 pixel texture is used to
http://www.kuju.com/http://www.microsoft.com/games/trainsim/http://www.kuju.com/http://www.microsoft.com/games/trainsim/


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map the roof, bogies, wheels, doors and pantographs but this texture contains a

transparency layer. The 64 x 64 pixel texture is used to represent the semi-

transparency of the windows at the side of the cockpit and the front windows.

Most shapes wouldnt need or have this amount of textures but as this shape is a

highly complex one and is in the users view all the time, it has to look very sharp.

When using the transparency layer/channel in your texture it is important to rememberthat there is a degradation of colour that occurs. The following is a guide to this.

Every texture is made of a Red, Green, and Blue channel but there are other channels

available to use for transparency and alpha. RGB Red, Green, Blue, RGBT Red,

Green, Blue, Transparency (4 channels) and RGBTA Red, Green, Blue,

Transparecny and Alpha (5 channels):

RGB = 16.7 million colours (True Colour 32 Bit)

RGB = 65536 colours (High colour 16 Bit)

RGBT = 32768 colours

RGBT designated transparent colour = 65535 colours

RGBTA = 4096 colours

There are two RGBTs which is purely a hardware issue as to what graphics cards

support which type of format.

To summarise:

The image must be flattened so that only one layer exists

The image must be converted to an Ace file format.

The image must be square and follow convention (512x512, 256x256 etc)

Use space within the texture efficiently.

Use transparency and alpha only where needed.

Try not to use a 512x512 pixel texture unless the shape definitely needs it.


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Modelling.When creating a complex shape like a train, the volume of polygons used is of

importance and will affect the scene frame rate. A general guide is the Acela shape;

this consists of around 3500 polygons but is a very complex shape.

The creation of a train also needs to stick to a strict object naming convention, this isso that the code can move the train engine properly and allow it to react properly to

its environment. As follows:

Acela Node Hierarchy Set

Main Engine

PantographTop1

PantographBottom1

PantographTop2

PantographBottom2

Bogie1

Wheels11

Wheels12

Bogie2

Wheels21

Wheels22

MirrorRight1

MirrorLeft1

WiperArmLeft1

WiperBladeLeft1

WiperArmRight1WiperBladeRight1

or as in the Flying Scotsman shape:

Flying Scotsman Hierarchy Set

Main

Bogie1

Wheels11

Wheels12

Bogie2

Wheels21Wheels22

Piston

Rod01

Rod02

Rod04

Rod03

Scotsman

Wheels1

Main_Wheel_Link

Rod06

Wheels2Wheels3


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The following is a list of all predefined object names that allow the user to create

carriages and trains and other such complex shapes. These objects must be linked to

the main shape with the main object being used as the parent to all shapes:

Rotating wheel sets where Wheels are children of Bogies.

Bogie1 + Bogie2 (Main Bogie shape node names)Wheels11 + Wheels12 (Wheel sets as children for Bogie1)

Wheels21 + Wheels22 (Wheel sets as children for Bogie2)

Pantograph types for various configurations (Parent is from bottom upwards)

PantographTop1

PantographBottom1 (Standard two arm pantograph nodes)

PantographTop2

PantographBottom2 (Second standard two arm pantograph nodes)

PantographTop1A (Other 3 arm types)

PantographMiddle1A

PantographBottom1APantographTop1B (Other 3 arm types)

PantographMiddle1B

PantographBottom1B

PantographTop2A (More 3 arm types)

PantographMiddle2A

PantographBottom2A

PantographTop2B (More 3 arm types)

PantographMiddle2B

PantographBottom2B

Mirror nodes with Arm being parent to Mirror.

MirrorArmLeft1

MirrorLeft1 (Left of driver mirror nodes (used on Acela class))

MirrorArmRight1

MirrorRight1 (Right of driver mirror nodes (used on Acela class))

Wiper nodes with Arm being parent to blades.

WiperArmLeft1

WiperBladeLeft1 (Left of driver wipers with Arm as parent to blade)

WiperArmRight1

WiperBladeRight1 (Right of driver wipers (above for hierarchy))

Main wheels used as driveable wheels.

Wheels1, Wheels2, Wheels3, Wheels4 (Main standalone wheels (steam engines) and

all rotatable wheels to be used on trains and carriages)

Arm rods for driving the driveable wheels.

Rod01, Rod02, Rod03, Rod04, Rod05, Rod06 (Arm rods for steam engines)

It is recommended that pivot point operations are carried out before any hierarchy

assignment is done as this can affect the animations assigned.


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So to summarise:

Set units to metres.

Keep polygon numbers low as possible.

Make sure all nodes are linked to a parent apart from the main node

Make sure all shared vertices are welded.

Align all pivot points to the world and centre apart from main node which is

centred and put at bottom.

Check smoothing groups or assign them to polygons.

Assign correct material names

Creation of a Complex Shape

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