Hi

Like most people, I think, I've been very impressed by the animations uploaded by ber7. Unfortunately I've found them a bit difficult to understand (old age I think) so I've written and annotated a very simple one of my own:
https://smath.com/wiki/GetFile.aspx?File=forum_attach/bdrunagle/SimpleAnimation.zip

I hope it's correct, useful, and not too simple for this forum.

Regards

Brian

Very clean and good example. If I am not mistaken, there are only two tentative corrections for the code. Instead of

(0,0,".",10,"Blue",1,5)
(0,0,"O",10,"Blue",1,5)

you should use previously defined variables Ox and Oy

(Ox,Oy,".",10,"Blue",1,5)
(Ox,Oy,"O",10,"Blue",1,5)

Thanks very much for spotting that IVR. It's updated:
https://smath.com/wiki/GetFile.aspx?File=forum_attach/bdrunagle/SimpleAnimation.zip

Brian

If Ox≠0, Oy≠0,
third and fourth line must be corrected:

Cx=Ox+OC*cos(δθ*t)

Cy=Oy+OC*sin(δθ*t)

Regards,Ber7

Thanks ber7.

It also needs
Py:=Oy
Piston:=…Oy+Piston_radius
etc, etc

I want to tidy it up a bit more but I've run out of time for now. I'll check it over the coming week.

Regards

Brian

Here is the updated animation.
https://smath.com/wiki/GetFile.aspx?File=forum_attach/bdrunagle/SimpleAnimation2.zip
Varying the values of Originx and Originy shift the animation as expected

I tried to tidy it up even more. In the above example, the origin is passed to the plot function using two parameters, Originx and Originy. I tried to pass the same values using a two-element vector, Origin, but without success: now I get a "t not defined" error in the 2D plot. To be consistent I also changed all the *x and *y parameters in the function to two-element vectors.
https://smath.com/wiki/GetFile.aspx?File=forum_attach/bdrunagle/SimpleAnimation2a.zip

Is there a special way to pass vectors to a function?
Is there a special way to define a vector inside a function?

Sorry, I'm still learning about SMath
By the way, I'm running SMath 0.93 on Windows 7

Regards

Brian

Slightly corrected your file,Regards.
https://smath.com/wiki/GetFile.aspx?File=SimpleAnimationM.rar

Square wheel
A square wheel rolls smoothly on inverted catenaries
References
G. B. Robison, Rockers and rollers, Math. Mag. 33 (1960), 139–144.

https://smath.com/wiki/GetFile.aspx?File=square_%20wheel.rar

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