# The Rocket Steam Locomotive TEST ANIMATION

Here is my first test animation of The Rocket Steam Locomotive tutorial. I noticed some artifacts and I still want to do more on it, but I think the first test came out pretty nice.

This was rendered with Blender’s Network Renderer on two computers. The first computer ran as Client, Master, and Slave within Linux, and the second computer was another Slave running in Windows Vista.Β It took roughly 9 hours for the full render with 4 errors that I had to render out as individual images.Β It was then thrown into Blender’s Video Sequencer and sent out as an mpg.

Jeremy Deighan

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Sooo awesome!!!! And it all started with a square!!! π love you!

Awesome! I wonder how you animated the wheels to make it in sync with the tracks…

Are you talking about the timing of the wheels? It takes some math which is explained in the tutorial but it goes something like this:

First we will say that 1 blender unit is equal to 1 foot to make it easy. I apologize if you are using metrics but in the USA I’m more used to feet/miles. You can use the same formulas as I will describe but for the sake of my sanity I’m just going to use feet/miles for now.

Find out how many units it takes to get from point A to point B. Let’s say that the animation is for a car driving down a residential city street, and for ease of math say its exactly 100 blender units (feet) from 1 road block to the next. Say even stop sign to stop sign. So our starting position will be 0 on the X Axis and will eventually end up at 100 on the X Axis where the car will travel to.

Next we need to find out how many times (or degrees) the wheel must rotate to get from point A to point B. We will need to find the circumference of the wheel. Circumference is defined as the actual distance around a circle (or the wheel in this instance). You find the circumference of a wheel by multiplying pi (3.14) times the diameter of the wheel, which is the distance from side to side of the circle (wheel). For ease of math again, lets say when we look in the front viewport of the wheel we know that it’s 5 units from the bottom of the wheel to the top. So our equation is:

Circumference = pi X d , or 3.14 X 5. The answer for the circumference is 15.7 blender units.

So every rotation of the wheel (360 degrees) needs to move the object 15.7 units. If we divide how many units we are moving by the circumference of the wheel, we’ll know how many times the wheel must rotate 360 degrees. It looks like this:

100 units / 15.7 units = 6.37 times. The wheel must rotate 360 degrees 6.37 times. Another way to say this is:

6.37 times X 360 degrees = 2293 degrees. So the object will rotate 2293 degrees from point A to point B over the 100 units.

Now we need to calculate how long it will take to move the vehicle from point A to point B. Since it’s a car in a residential street we’ll assume that it will be driving about 20 miles per hour. Since we are using feet (units) for our animation, we’ll first need to convert the miles per hour to feet per second. First we need to know how many feet are in a mile and how many seconds are in a hour. That’s simple:

1 Mile = 5280 Feet

1 Hour = 3600 Seconds

To start converting, we will multiply how many miles per hour we’re driving times how many feet are in a mile. Then we will divide that number by how many seconds are in an hour. The formula is as followed:

20 mph X 5280 feet = 105600 feet

105600 feet / 3600 seconds = 29.33 feet per second.

If our vehicle is travelling at 20 miles per hour than it’s also going 29.33 feet per second. We can divide how fast it’s driving by how many feet we want to go to find out how many seconds it will take to get there.

100 feet / 29.33 feet per second = 3.41 seconds to travel 100 feet (units).

Blender’s default frame rate is 24 frames per second. So:

24 frames per second X 3.41 seconds = 81.84 frames.

It will take about 82 frames to travel 100 units from point A to point B and we will need to rotate the wheel 2293 degrees over the course of that time.

So at frame 1, we put the vehicle at 0 on the X Axis, make sure the wheel is 0 degrees on the Y Axis, and set a location keyframe for the vehicle and a rotation keyframe for the wheel. Then we move the timeline to frame 82. Move the vehicle 100 units on the X Axis and rotate the wheel 2293 degrees on the Y Axis. Set another keyframe for the vehicle and the wheel. Depending on which way you are moving the object, you may need to set the rotation of the wheels to -2293 degrees.

When you play the animation, the vehicle moves along the X Axis 100 blender units within 3.41 seconds and the wheels rotation accordingly. I hope this sums up what you were asking and feel free to comment if you need more help!

Jeremy Deighan

I would like to thank Neal Hirsig for his wonderful explanation on this method. You can find the locomotive tutorial which explains this as well as many other wonderful tutorials at:

Blender 3D Design Course

cool!

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Wonderful article it is surely. My girlfriend has been looking for this update.