## Spirograph/Double Pendulum help

The Partridge Family were neither partridges nor a family. Discuss.
AleksiyCODE
Posts: 32
Joined: September 21st, 2019, 8:47 pm

### Spirograph/Double Pendulum help

Hey!
So, recently I made a 3D spirograph (based on HW3D framework ofc).
https://imgur.com/a/ggfstr0 - some pics
The most interesting thing about it - is the ability to observe the shape being drawn from 1st person.
Controls:
space - pause/continue
esc - switch between camera movement and using IMGUI (just like in default HW3D framework)
q - quit
change camera mode to view from 1st person (looks better when some complicated shape is already finished and you are tracing it for the second time. Resembles a view from a spaceship cock_pit)

However, initial idea was to make a 3D path tracing double pendulum. Sadly, I could not do it(
There is quite a lot of information about double pendulum on the internet, but very little about 3D version of it. To be exact, I didn't find a single useful formula. Ideally, something like CodingTrain uses in this https://www.youtube.com/watch?v=uWzPe_S-RVE video at 15:00.
Deriving such formula seems way too tedious, so I gave up.
If someone knows where to find the formula, please, let me know.
I like ass

albinopapa
Posts: 4289
Joined: February 28th, 2013, 3:23 am
Location: Oklahoma, United States

### Re: Spirograph/Double Pendulum help

I've used some of his stuff before like ray casting, but for some reason I can't stand his personality. He's a bit too eccentric for me lol. Smart guy though.

As for the double pendulum, that's pretty neat and getting it to work in 3D I would imagine would require quite a bit more considering the extra dimension. Instead of angular velocity around just the Z axis in 2D, you now have to deal with X axis and Y axis as well. Maybe look up forward kinematics or inverse kinematics, maybe something similar to joint rotations.
If you think paging some data from disk into RAM is slow, try paging it into a simian cerebrum over a pair of optical nerves. - gameprogrammingpatterns.com

AleksiyCODE
Posts: 32
Joined: September 21st, 2019, 8:47 pm

### Re: Spirograph/Double Pendulum help

Hmm, I doubt this will be enough on itself, but thanks for the tip!
This stuff might help, if one day I find some formula, but it is not trivial to use.
I like ass

AleksiyCODE
Posts: 32
Joined: September 21st, 2019, 8:47 pm

### Re: Spirograph/Double Pendulum help

No one cared, but we did it anyway!
New release with cool shaders, ability to import and export, new camera mode, fast forwarding and more!
There is even a user's manual!