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Thanks for the comment. I made the above spiral scene by cloning one tooth onto a log spiral, then using the pen tool to join start to end. The hard part was where the start on one cog meets the end on an adjacent cog. I made an instance of the working cog spline and flipped it 180 deg to represent a 2nd, so I could tweak the points until they fitted. The center cog is an animated collider and the other 2 rigid bodies - so it runs on dynamics. I only started this little quest after seeing 'impossible' gears (eg square) on YouTube, wondering if it was a con, then building them in C4D as a test. I usually check for any movement of object centers or hinge positions in attrib manager when the model is running, as proof of concept. 3 spirals.c4d

You mean this pie ? re @noseman and pi degrees are defined as 1/360 of a full rotation, but radians are defined by the arc radius malarkey - not by the division of a circle, so radian does not "include pi". The reason 360 deg = 2 pi radian is due to the definition of pi ie C = 2 pi R. ...changes username to Mr Pedantic...

@noseman I've actually seen solutions to the car wheel problem using the degree node twice, and bringing 360 into things 😁 For any radian noobs - a radian is the angle at the centre of a circle when the arc equals the radius. In this pic the red X is distance travelled by the car. Solving for A gives angle = distance / radius pi is defined by circumference = 2 pi R, but since we are not bothered about complete wheel rotations, pi doesn't really come into this calculation. Radian does not 'include' pi IMHO.

Interesting use of Tracer @noseman - no need to use pi twice though...

You can add incrementally by reading the current rotation value and adding to it every frame wheel.c4d distance is always positive, so only works for the car going forwards. There's some clever code written by Base 80 that allows for forward and reverse. You make your wheel a child of the Base80 wheel eg wheel2.c4d BaseWheel1.7.c4d adjust the Base80 wheel to same radius as the real wheel. Only move Base80 wheel by parent null.

Since some of you liked my log spiral video, here's a variation - some other gear stuff -

Try this OrbTest3.c4d note XPresso uses radians - hence the 2 pi

@Hrvoje I understand how to represent polar coords in cartesian in order to use formula spline. By 'differ' I meant you find it a good way to get a log spiral and I don't. Converting 1 equation with 2 variables into 2 equations with 3 variables - an extra unnecessary variable t - makes things more complex IMHO. Those 2 equations do not shout out 'spiral' to me, but the polar version does. I must admit that my approach to C4D is to use math, XPresso, Python etc and ignore built-in functions that I haven't bothered to learn about. A frequent comment on my stuff is 'there's a field that can do that'. I have, of course, never tried to learn fields...

I used to think square cogwheels were just another fake YouTube thing, but I've almost got it sorted. Still WIP

I think we're going to have to agree to differ on this.

@Hrvoje can formula spline use polar coordinates ie radius + angle ? Spirals are easiest described (and understood) using polar vs cartesian. TBH I've never really understood what 't' is in formula spline. in math - y = f(x) ie y is a function of x in C4D x = f(t) ie x is a function of t y = f(t) ie y is a function of t

@rasputin I just used the general log spiral equation where angle is in radians, e is the natural log base (aka Euler's number 2.71828) and tweaked the constants a + k until it looked right. I tried using a helix and radial bias but the gears were jumping. I guess it's the properties of logs that makes it work. Also, when I added the struts, with a helix I had to use a spline on the step effector to make things fit, but with the log curve the struts fitted without a spline. I usually animate gears with XPresso, but with the varying radii that would be beyond my math skills. Dynamics to the rescue ! The video above is version 2 - I didn't like how dynamics had introduced a small collision gap, so after baking for TR I increased the teeth size. The dynamics is Compound Collision Shape, but with all the geometry it was too slow in the viewport. I added some switched off rigid body tags to parts that don't contribute to the dynamics calculation. Here's the video I got the design from. The guy has some good stuff eg non-circular gears I'm still trying to figure out square gears...

I saw a video on YouTube by a guy who makes kinetic art mobiles. He had an interesting one made out of toothed spirals, so I had a go at recreating it in C4D. I tried using a helix spline, but couldn't seem to get the objects to interact correctly, so I made a proper log spiral using tracer. The movement is generated using dynamics - there's one collider that's rotated in XPresso driving 2 rigid bodies. demo.c4d https://en.wikipedia.org/wiki/Logarithmic_spiral make log spiral.c4d

Some more of my Reuleaux Triangle experiments - in this scene, the rotor is a collider rotated with XPresso. The fixed width parallel bars are a rigid body on a slider connector, and C4D dynamics does the rest RT parallel.c4d here's the same thing in a rigid body rectangle that is on a planar connector. The square moves, so the camera is parented to it making it appear stationary RT in square.c4d if you make the Reuleaux Triangle from the default size N-side, it fits exactly into a honeycomb cloner RT honeycomb.c4d this vehicle with Reuleaux wheels on a keyframed tilting surface rolls at constant height RT wheels.c4d I think that's enough wobbly wheels for this week 😀

Reuleaux triangles are weird https://en.wikipedia.org/wiki/Reuleaux_triangle well, it amused me 😀 reuleaux2.c4d

Re teeth ratio - are you familiar with the Looney Gears ? It's a toy with asymmetric sun + planet gears that have prime numbers of teeth. The game is to work out how many times you have to rotate the sun gear to get all the gears lined up. There's also Somsky gears, with an extra cog. My version -

The math problem I encountered was that for one cog to drive another they must have the same linear speed at the point of contact. For a given rotation speed, the edge speed is proportional to radius, and the cogs have varying radius. I found some equations on Wiki etc, but it was beyond my math ability ☹️

I like to make stuff with gears and normally use XPresso or Python to get the required rotations. Recently I needed to use oval gears, but the math proved too hard. I thought I'd try C4D dynamics, not really expecting it to cope with non-circular gears. To my surprise everything worked - so I made some 3, 4, 5, 6 etc sided cogs and dynamics worked for those objects also (with a bit of help from constraints and XPresso). Using wheel suspension instead of hinges helps to keep odd shaped things things touching. Here's a video of my tests While I had my math hat on, I made this - no idea what it's supposed to be.

Rendered quite fast on my Ryzen 3700X.

It's fairly easy to use. You make the scene in AE - shapes etc, then click Newton which opens the scene in the app. Adjust gravity, velocity, friction etc and click render. That returns a copy of the scene back to AE with keyframes for position. In my clip, I made a circle shape bounce in Newton, and used the shape as a mask to reveal the alternate text (with distortion).

I had a tinker with Newton 3 recently. It's a Physics plugin for After Effects that can give AE shapes velocity, friction, bounce etc. Also has springs + levers, https://www.motionboutique.com/newton/ My first scene -

It's not the kind of animation that can be made into a loop. Although the head is driven by a sine node (itself a looping function), the rest of the body reacts dynamically. The start position is never repeated. +1 to Turbosquid for the nice free model.

The problem for anyone starting out wtih C4D Python is that the MAXON Python site is IMHO very complex and intimidating (maybe I should be generous and say 'very thorough' 😀 ), whilst most YouTube Python tutorials are about Python in general - not relating to C4D. Cairyn's series of blogs fills the gap between those 2 extremes, in that it's about learning to use Python in C4D. I've just read the 1st 8 posts and I'd say it's a good place to start for C4D users with no coding experience. Recommended.

Sorry, I don't know the answer to that.

It's how Python marks out blocks of code eg a conditional statement or a for loop controls the lines below that are indented.