"koppi" <jak### [at] gmailcom> wrote:

> I just have fixed the domino orientation along the spiral as you have suggested,

Perfect.
Now set up all the dominoes like so:

https://news.povray.org/povray.advanced-users/attachment/%3Cweb.659879b9cca34dee1f9dae3025979125%40news.povray.org%3E/m
athpatterns1.png

:D

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"Bald Eagle" <cre### [at] netscapenet> wrote:
> Now set up all the dominoes like so:
>
>
https://news.povray.org/povray.advanced-users/attachment/%3Cweb.659879b9cca34dee1f9dae3025979125%40news.povray.org%3E
/m
> athpatterns1.png

Bill, do you mean I should arrange some self similar, some sort of fractal
domino arrangement to the playground? - That's an interesting challenge!

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"koppi" <jak### [at] gmailcom> wrote:

> Bill, do you mean I should arrange some self similar, some sort of fractal
> domino arrangement to the playground? - That's an interesting challenge!

I was only half-joking, but if you can make it happen, then YES!

That pattern is from a shader on ShaderToy by Fabrice Neyret.  It was only like
6 lines of code.

Might help, might make it more confusing.

You might also have to consider adjusting the size of the dominoes as the
spirals get longer and the spacing is limited.

- BW

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"Bald Eagle" <cre### [at] netscapenet> wrote:
> That pattern is from a shader on ShaderToy by Fabrice Neyret.  It was only like
> 6 lines of code.
>
> Might help, might make it more confusing.

Foud it: https://www.shadertoy.com/view/XtSBDK
Will see, what can be done with it inside BPP ;-)

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"koppi" <jak### [at] gmailcom> wrote:
> "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,
>   }
>   [...]
>

I basically did the same but written in POV3.7.


> 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?
>

I'm a little late on this one, as you already have a better way than I have. I
wrote the spline starting from the outside in like normal. Then translated all
the control points so the outer point was <0,0,0>. That because these spirals
where made to be part of a bigger Field of dominoes and also be able to use a
spiral over & over & .....
 I use this spline to hunt down each domino point that was 2 pov units from the
last domino placed. I started at 0 +some very small number (.0001 I think) then
keep adding that small value until I got vlength(Oldpoint,Newpoint) =2. The only
problem was at the very end when the search point goes out of range. So I put a
Stop Gap if the search counter got to big.(.1 is to big) not very efficient.

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

Have Fun!

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