Steam Locomotive Toy Documentation

March 16th, 2024 - Project exploring the use of hscript for creating procedural animations in SideFX Houdini

Sampling

● Pixel Samples - 6x6

● Min Ray Samples - 1

● Max Ray Samples - 9

● Noise Level - 0.01

● Global Quality - 1

● Diffuse Quality - 1

● SSS Quality- 1

● Reflection Quality - 3

● Refraction Quality - 1

● Volume Quality - 1

● Volume Step Rate - 1

● Volume Shadow Step - 0.25

Rendering Statistics

● Renderer - Mantra PBR

● Average Render Time - 8 mins / F

● Image Resolution - 1280 x 720

● Number of Lights - 2: HDRI(Fill) and Area Light(Key)

● Geometry Complexity - 50,000 poly Vehicle

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This was a project created for my “Procedural Modeling and Animations Techniques” class taught by Deborah Fowler. In this project I utilized hscript in order to explore the possibilities of creating animations with minimal keyframing.

Steam Locomotive Toy Documentation

Mechanical Breakdown ⚙️

Most moving pieces of this vehicle operate by some use of $F, abs(), sin(),and cos(). A lot of the mechanisms relating to the front engine of this train car do not really have a mechanical purpose but make it look more robust.

As the middle pieces rotates by a user specified speed The arm moves in a circle to mimic how the pseudo-engine pushes against the arms:

The piston arms move in a similar fashion but with some magic numbers to make it move with the other pieces.

Translates the piston along the x-axis by a sin wave offset by 8 frames to match the flow of the other pieces.

Steam Locomotive Toy Documentation

Mechanical Breakdown ⚙️

The gear system is an HDA from my orrery project.

The axle system was straightforward, making sure that the objects rotate at the same time when the user adjusts a parameter. The tires and all mechanics are based off a user defined “speed” parameter.

Steam Locomotive Toy Documentation

Resources 📘

Professor Fowler’s Website:

https://deborahrfowler.com/

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Houdini Motion Blur Documentation:

https://www.sidefx.com/docs/houdini/render/blur.html

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Toy Train Reference:

https://www.youtube.com/watch?v=hCQTcZ4e-oY&list=LL&index=16