[Plugin] Center of Gravity

Pockocmoc

Oh, and even with a simple cube, (wich is solid) it does the same : no weight...

TIG

What version do you have ?
It should be v1.7 from the SketchUcation PluginStore ?
It's 3 years old but works on newer SketchUps anyway...

If you run it with the Ruby Console open are there any error messages ?

What settings are you using ?

What is getting reported exactly ?

Obviously the object's size versus the chosen density units can cause small objects to be reported as 0...
A small 'blade' probably needs to be in g/cm³ or similar...

Here's what I get with a component cube with protruding numerals [v2016].
It's a but over 1 m³ with a density of 2000 kg/m³ at the default 1% accuracy setting it returns a true volume in m³ and a weight in kg...
A much smaller [scaled] version reports '0' when the overly large units misapplied, but with g/cm³ it's fine...

Can you post a simple SKP that has issues so I can test it...

Box

It sounds like you may be creating component, but failing to tick the box that replaces the raw geometry with the component.
If there is no bounding box around your object it is just raw geometry, see if the component is in the component browser for you ready to use.

Pockocmoc

I am so stupid ... you are right TIG, it was because of the units, obviously! The blade weights 42 grams, so (0.0)42 Kg .

Thank you for all.

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...