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DavideB

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10-01-2014 03:04 AM

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Dear forum experts,

I have to draw a Reuleaux triangle (non-obvious constant width curve) using Labview, like the one in the attached somatochart file.

The program will be used in an anthropometry laboratory to indentify the somatotype (endomorph, ectomorph or mesomorph) of individuals.

Can you give mer any suggestions?

Thanks,

Davide

GerdW

Knight of NI

10-01-2014 03:38 AM

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Hi Davide,

use a XY graph and draw your curve.

What exactly is the problem?

Best regards,

GerdW

using LV2011SP1 + LV2017 (+LV2020 sometimes) on Win10+cRIO

GerdW

using LV2011SP1 + LV2017 (+LV2020 sometimes) on Win10+cRIO

10-01-2014 04:13 AM

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Dear Gerd,

I understand I am missing something... but the triangle is an area, not a function. The total area is 0.5(pi-sqrt(3))R^2.

R is the constant radius of the three intersecting circles.

Actually, I have no clue where to begin from...

Thanks,

Davide

GerdW

Knight of NI

10-01-2014 04:20 AM - edited 10-01-2014 04:20 AM

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Hi Davide,

you need to know the inner triangle. Once you know its corner points you can draw arcs (or better: calculate XY points for a plot). It looks like simple geometry math!

Now I looked at Wikipedia and I can also suggest to use a 2d picture indicator for your Releaux triangle plot. Here you could use draw functions directly instead of calculating points in a XY graph…

Best regards,

GerdW

using LV2011SP1 + LV2017 (+LV2020 sometimes) on Win10+cRIO

GerdW

using LV2011SP1 + LV2017 (+LV2020 sometimes) on Win10+cRIO

10-01-2014 04:24 AM

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Thanks Gerd,

the inner triangle is equilateral, the side being R.

What is a 2d picture indicator?

Thanks

Davide

GerdW

Knight of NI

10-01-2014 04:33 AM - edited 10-01-2014 04:34 AM

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Hi Davide,

apply some basic math to calc the corner coordinates from your R value…

The 2D picture indicator is explained in the LabVIEW help!

Best regards,

GerdW

using LV2011SP1 + LV2017 (+LV2020 sometimes) on Win10+cRIO

GerdW

using LV2011SP1 + LV2017 (+LV2020 sometimes) on Win10+cRIO