christianschmidt
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christianschmidt got a reaction from David in Яuislip in Center of gravity
Thanks! I left Inkscape for Affinity Design, but will check this out. Sounds good!
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christianschmidt reacted to John Rostron in Center of gravity
If your shape can be approximated as a polygon, then you can use the formula described in the Wikipedia article mentioned by @Old Bruce under 4.9 Polygon:
https://en.wikipedia.org/wiki/Centroid#Of_a_polygon
You should be able to do the sums with a spreadsheet.
John
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christianschmidt reacted to David in Яuislip in Center of gravity
Use Inkscape:
Draw a path or use a shape converted to path
Then do
Extensions: Visualize Path: Measure Path
Set Measurement Type: Center of Mass
Apply
Red is rotated ellipse
Green is distorted duplicate
Blue is as green but with the hole
No idea about the accuracy, my days of calculating CoG's are long gone
CoGs.svg
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christianschmidt reacted to Old Bruce in Center of gravity
Lots of maths. Check out the Wikipedia page for Centroids of Polygons.
https://en.wikipedia.org/wiki/Centroid
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christianschmidt reacted to NotMyFault in Center of gravity
Regarding how to mark the CG: lots of options, e.g. adding a star, circle, whatever you like and nest it to the object.
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christianschmidt reacted to NotMyFault in Center of gravity
If using 2D shapes there should be a simpler solution. We could count pixels (having the color of the shape) over x and y axis. This is what histograms and scope panel do support in principle. Unfortunately we won’t get the numbers, only the diagrams.
Affinity might not best suited, but it should be simple to write a script in any language capable of reading image files doing the math.
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christianschmidt reacted to Old Bruce in Center of gravity
No!
Affinity's centre of rotation is an aid for drawing, nothing else.
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christianschmidt reacted to NotMyFault in Center of gravity
There is no general solution.
In principle you would need to laser cut the shape and put it on a rope in 2 different positions.
https://www.grc.nasa.gov/www/k-12/airplane/cg.html
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christianschmidt reacted to GarryP in Center of gravity
Welcome to the forums @christianschmidt
Can you explain what you mean by “centre of gravity” please?
You can use and change the centre of rotation by changing the Transform Origin as can be seen in my screenshot.
If that’s not what you want then you will need to give more information.
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christianschmidt got a reaction from NotMyFault in Center of gravity
Thank you Garry & NotMyFault! Background of my question is that I am constructing Mobiles. The elements for the Mobiles I cut out with a lasercutter. When using shapes like "plates" – see picture – or any other flat objects I have to find out the center of gravity. I am aware that I have the option to SEE the center of rotation (supposing that this is the same like the center of gravity), but I also want to MARK it. I can mark the center with the pencil, but then I have to enlarge a lot and the result is still not very precise.
@NotMyFault: I came across the NASA explanation. Thanks for that. But having a CAD app, a lasercutter and being not very good in math, I hope for a simpler solutiion...