[Math/3DS] Question - Rescaling formula to recover the original dimensions of a model?

Ace-Angel

Hey to all,

OK, here is the deal. I have a model that I scaled up to 150% from the original value, exported it for an edit, and if I want to rescale that model BACK to it's original 100% on importation, I basically have to scale it down to 66.666666666%.

So this means, 100% model SCALED to 150% SCALED to 66.666666% would return my model BACK to original 100% value.

The problem is, I'm not good at math, so I'm figuratively lost as to what even the math numbers behind that are? I even tried googling if there a formula to this, so can reference it in the future when exporting/importing models between apps, and changing their scales, but I couldn't find diddly-dong about it.

Any one know what the magic theorem is called, or if there is actually formula I can keep on hand?

Cheers in advance!

Axi5

If you know the size of your model and the percentage you originally scaled by you could do:
(height / scale%) * 100

Let's say original scale was 2.2 units tall in Y and then it was scaled to a new value of 1.5x that/

Find the new height by using a measuring tool, or bounding box min/max. In this example it'd be 3.3

3.3 / 150 * 100 = 2.2

I think in order to calculate the 66%, you would need to know both of the individual values rather than the percentages.

Handy trick with percentages. You can skip the *100 part if you just consider 1 as your 100%.

150% of 1 is the same as 1.5 * 1. It makes things quicker to calculate! 

Edit:
Oh just realized, 100/150 * 100 would give you 66.6666r which is exactly the value you want

Ace-Angel

Cheers Axi, seems like the math so far is adding up.

And the previous formula you gave me was very useful for some 3D printing issues I was having, cheers!