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Gmax Animation Tutorial

In this tutorial you will learn how to animate the fan blades for a locomotive. The methods used to create the fan animation can be adapted to any Trainz object.

Note. To complete this tutorial you will need to have available a model that has already been textured and has an unwrap UVW modifier applied to it. You can get the demonstration file here.

 

1. Sample files

The following screen shot shows the model I am working with. There are two items in this model the fan guard and the fan blades.

 

Figure 1 Fan

 

2. Dummy objects

The first item we need to add is a bone or dummy item. To add a dummy item in Gmax you need to go to the "Create" tab and then to the "Helpers" tab

 

Figure 2 Dummy menu item

 

In this case you will need to create two dummy items. It is recommended to create the dummies in the top view. Once you have created the dummy items you will need to rename them. For animation to work in Trainz the dummies must begin with b.r.   If you do not name them correctly then Trainz will not recognize them.

For this example I will name them b.r.main and b.r.fans1

 

3. Dummy placement

Once you have renamed the dummies you will then need to move the dummies to the correct location. The b.r.main should be moved as close as possible to 0x and 0y. The Z axis I usually keep the dummy about 200mm or 8" above 0. The location is not that important.

The location of the b.r.fans1 is however critical as it is what controls the animation. For the fan blades the dummy needs to be at 0,0,0. If it is not at this location then the fan will appear to oscillate when the animation is running.

4. Linking

Once the dummies are in location we can then start linking the items together. To link them together first select the link button and then select the item

Figure 3 Link tool

 

To make it easier to see if a link has been made I usually change the view setting to "wireframe" which can be done by right clicking on the text in the top left corner of the workspace.

You need to create the following directory structure which can be shown by pressing H:

 

Figure 4 Directory structure

 

You may need to check the box "Display Subtree" to show the structure.

 

5. Time rate

Once you have this directory structure we then need to set up the time rate for the animation. To do this we need to click on the following icon located in the bottom right hand corner.

 

Figure 5 Time setup button

 

Once you have the window shown in figure 6 open we need to change the Animation start and end time.

 

Figure 6 Time configuration menu

 

The easiest way to do this is to select the "Re-scale Time" button which will open the following window

 

Figure 7 Re-scale time window

 

Where it says frame count, change the value here to 31 frames. Some people use a different number here but I find 31 gives a good smooth animation. Once you have changed the frame count click OK and the animation start time should be the same at 0 but the end time should now be 30. If the "Track Bar" is not visible at the bottom of the screen then you will need to turn it on. To do this go to the "Customize" menu and the "Show UI" and select "Show Track Bar" from the menu.

Figure 8 Turning on the Track Bar

 

 6. Animation

Now we are ready to start the actual animation of the fans. Firstly select the b.r.fans1 dummy. Then select the rotate tool.

 

Figure 9 Rotate tool

 

Figure 10 Animation keys

 

In Gmax you will then need to select the animate button (See figure 10). Before you move anything you need to make sure that everything is in the correct starting location.

 

Figure 11 Keyframe1

 

This will allow a base key or zero key to be created as shown in Figure 11 which is the starting point of the animation. We now need to move the animation to the next key. Select the bar between the arrow keys as shown in figure 11 and move it to the right and frame 1 will be selected. Make sure you have the rotate tool selected as shown in figure 9.

Once you have moved to frame 1 select the text in the z: co-ordinate box and type in 12 then press enter. If you have every thing linked correctly and the correct dummy selected then both the dummy and the fan should have rotated 12 in a counter clockwise direction (looking from the top) and two new keyframes should have been created one at 0 and one at 1.

 

Figure 12 Rotate co-ordinates

 

Figure 13 Animation keys

 

7. Testing

When you have created a key for each frame you can test out your animation by clicking on the "Play Animation" button. If the fan oscillates then you did not have the dummy located at the center of the fan. If it seems to skip or pause then you may have missed a step when setting keys. Check each key manually and make sure that each frame number has a rotation value as set out in the table below. If you have missed a key then you will need to redo any of the keys that are incorrect. You can also have problems when using Gmax to create the values in between if you did not specify the correct value for the correct key then Gmax will calculate the rest of the values incorrectly and you will have to start again.

Degrees
Frame
Shortcut
0
0
0
12
1
  
24
2
  
36
3
  
48
4
  
60
5
  
72
6
  
84
7
  
96
8
  
108
9
  
120
10
  
132
11
  
144
12
  
156
13
  
168
14
168
180
15
180
-168
16
  
-156
17
  
-144
18
  
-132
19
  
-120
20
  
-108
21
  
-96
22
  
-84
23
     
-72
24
  
-60
25
  
-48
26
  
-36
27
    
-24
28
  
-12
29
  
0
30
0

 

8. Exporting

Once you have the animation complete then we need to export the fan to the Trainz format. Deselect everything and select "Export" from the file menu. Type in a name with the .im extension. Then select the "Trainz format [*.IM,*.KIN,*.PM]" entry from the file type drop box and click "Save". Then select "Export" again and this time type in a name and use the .kin extension. When the "Export Animation" dialog box appears click on the "OK" button.

 

9. Config entries

Now that you have exported the file into the Trainz formats you will need to set up a directory structure and create a config file with the line "animdist X" for bogeys with the X being the circumference of the wheel in metres. For scenery, locomotives, interiors and rolling stock the animation needs to be set up in the config file. Animations can be controlled with a script or they can be set to auto run.

 

 

 

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Copyright © 2007 P. Campbell. All rights reserved. Revised: June 13, 2007