[Plugin] Center of Gravity

hute_zhaw

Hi Folks

I just installed this plugin into SketchUp 2017. It doesn't work as expected for me. The find CofG still works fine as far as I can tell but the Composit CofG returns a ruby error:

Error; #<TypeError; reference to deleted Group>
/Users/hute/Library/Application Support/SketchUp 2017/SketchUp/Plugins/CofGravity.rb;670;in `entities'
/Users/hute/Library/Application Support/SketchUp 2017/SketchUp/Plugins/CofGravity.rb;670;in `block in do_composite'
/Users/hute/Library/Application Support/SketchUp 2017/SketchUp/Plugins/CofGravity.rb;669;in `each'
/Users/hute/Library/Application Support/SketchUp 2017/SketchUp/Plugins/CofGravity.rb;669;in `do_composite'
/Users/hute/Library/Application Support/SketchUp 2017/SketchUp/Plugins/CofGravity.rb;117;in `initialize'
/Users/hute/Library/Application Support/SketchUp 2017/SketchUp/Plugins/CofGravity.rb;817;in `new'
/Users/hute/Library/Application Support/SketchUp 2017/SketchUp/Plugins/CofGravity.rb;817;in `block in <top (required)>'
SketchUp;1;in `call'

Has anybody got a clue how to fix this? It is really a pretty cool plugin and would be a shame if it became unusable.

TIG

Thanks for the bug-report.
I suspect that this is a glitch in the way v2017 handles exploded entities.
I'll investigate and fix it...

TIG

Here's v2.0 http://sketchucation.com/pluginstore?pln=CofG Its coding is now compatible with v2017 and it is also signed for use in v2016/v2017 in any loading-policy.

hute_zhaw

Outstanding work TIG, thanks that was quick, I can confirm it works after the upgrade of the plug-in.

Cheers

jbkbm

The plugin does not seem to be able to detect hollow spaces. Am I doing something wrong? I am trying to find the CoG of steel assemblies but when it calculates the weight, it includes the space between plates and gives me a number much higher than the actual weight.

TIG

Your image attachment isn't showing.
An object needs to be a sensibly formed 'solid' - as reported in Entity Info.
Otherwise results can be flaky...
'Hollows' are accounted for, if it's a proper solid...

If you attach your SKP we can look at it...

lsorrentino

Hello All, hello TIG,
I want to calculate the center of gravity of a small magnet, but the calculation always report volume = 0 and eventully weight = 0.

The plugin works perfectly on my pc with larger objects, the density is 7.6 g/cm3, I'm a newbie with sketchup in general, I'm probably doing something wrong

Luca

sketchup file

screenshot

result

TIG

It must be a rounding issue.
The object looks like it has no volume to SketchUp, therefore no weight.

I'll investigate...

TIG

Yes, I see it.
It was never intended for such small objects.
It rounds to the nearest cu", so your small object appears to have no volume !
I'll look at a way of adjusting it...

lsorrentino

Wow, very interesting. Thank you very much!

TIG

Here's v3.0 https://sketchucation.com/pluginstore?pln=CofG It now reports the Volume/Weight of very small objects with more dp etc...

lsorrentino

Thank you very much, I will use it tomorrow!

Luca

lsorrentino

It obviously works!!!

Thank you very much TIG, extremely useful plugin.

Luca

lsorrentino

Other little thing I can't understand.

The little magnets of my previous post goes attached to a wood base that according to sketchup is 4500 mm3, but calculated by CoG is 4000.

The volume of the magnet is ok regardless is far little than the wood base.

Bye,
Luca

sk1

lsorrentino

My feeling is that if the volume is only mantissa, ie 0.04555 cm3 works good, when volume is ie 4.75 cm3 decimal part is truncated.

Luca

TIG

Must be a glitch somewhere in the 'rounding'...
I'll fix it...

TIG

Here's v3.1 https://sketchucation.com/pluginstore?pln=CofG The rounding glitch on some small values is now fixed.
The Volume/Weight now shown with between 1dp and 4dp, suppressing trailing zeros beyond .0 as necessary.

lsorrentino

It works!

Thank you very much,
Luca

sketchartist023

Mine does not show up with the added component information. It just turnes the solid into a bunch of layers (horizontal lining). SU 8 Pro windows 7 64bit

TIG

Version 8 is by now pretty much unsupported, but it should still work.
If you have the Ruby Console open what errors do you see when it fails ?
It's clearly doing its temporary slicing to get the centroid... but not completing...

How big is this object ?

Can you upload the SKP you are having issues with...