Procedural
animation
Procedural Modeling & Animation
· Houdini
· Mathematical coding
· Procedural modeling & animation
Statement
A fully procedural project covering modeling, shading, and animation, inspired by Reuben Margolin’s Around the World with Cams. The piece recreates the device’s unique cam-and-lever mechanism, allowing a sphere to continuously travel along the wheel’s outer edge. Motion is driven by a series of mathematical expressions, with extensive controls provided for fine-tuning the animation.
该作品完全使用程序化的方式创建模型、材质和动画。作品灵感来源于Reuben的作品Around the World with Cams。该装置由背部的电机配合特殊的转轮和杠杆结构带动小球运动，使其能够完美地沿着轮盘外沿无限“爬行”。该作品还原了原装置的特殊构造，使用了一系列复杂的数学表达式来驱动装置运动，并且添加了大量的控件来对装置动画进行微调。
Process
A brief explain to the rod path calculation and disk shape(can also check this in the PDF at the end of this page)
Assuming the center will rotate, the ball must remain stationary when the rod is not raised (it must stay put in the dent).
The center of the rod does not align with the center of the wheel, and the rod's length is fixed. As indicated by the dashed line path shown in the figure above, it is impossible to keep the ball stationary without adjusting the rod's position. Therefore, we must modify the rod's position during motion. In other words, we need to alter the shape of the disk.
Therefore, we draw the adjusted rod pivot path with the ball as the center. In a cycle of 360 frames, we aim to keep the first 260 frames static while implementing the lift effect over the subsequent 100 frames. Thus, the path ratio between the two segments is 260:100.
We then draw the adjusted motion trajectory (green line). Compared to the original path (orange line), We can calculate the height the rod needs to be raised or lowered based on the distance between the two lines. I haven't calculated the exact value here, but we can manually adjust it later to get a value that's fairly close. Then we plot the function graph and use it as a basis to draw the shape of the disk.
Technical Documentation
See more process and technical details in PDF document here!更多流程和技术细节请看技术文档！
*The reel code is from Professor Debroah Fowler’s website: Dot Product - Two point constraint problem