POV-Ray : Newsgroups : povray.animations : Dominoes : Re: Dominoes Server Time
4 May 2026 17:21:05 EDT (-0400)
  Re: Dominoes  
From: koppi
Date: 1 May 2026 06:20:00
Message: <web.69f47d99cea3e23e993716b9199194f2@news.povray.org>
"Leroy" <whe### [at] gmailcom> wrote:
>  I was wondering how you place the dominoes. I use a spline for placement. I
> have my dominoes placed 2 pov units apart. That because I don't use true physics
> to move the dominoes.

Archimedean spiral calculation is used to create the control points [1]:

  [... line 47]:
  local angle = (i - 1) * 0.09
  local radius = 5 + angle * 0.95
  cp = {
    x = math.cos(angle) * radius,
    y = y_pos,
    z = math.sin(angle) * radius,
  }
  [...]

The control points are then fed to the Catmull-Rom spline function [2] with the
tension parameter set to 0.5.

>  Noticed that your dominoes have different spacing, they got tighter toward the
> center.

I would like to have equal spacing between the dominoes, but I do not know how
to calculate that, do you have an idea?

> Your physics engine did a good job of dropping them. I also like the
> wiggle the engine gave to the already down dominoes.

I have been experimenting with different parameters for the friction,
restitution, linear and angular damping of the dominoes, currently using:

  friction = 0.01
  restitution = 0.01
  damp_lin = 0.5
  damp_ang = 0.01

Kind regards,
koppi

--
[1]
https://github.com/bullet-physics-playground/bpp/blob/b558bdf8e8ab23a1438d0162d40c7f0029eb3efd/demo/basic/11-domino.lua

[2]
https://github.com/bullet-physics-playground/bpp/blob/b558bdf8e8ab23a1438d0162d40c7f0029eb3efd/demo/module/spline.lua#L
134


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