...exactly as illustrated in figures 1 to 4.

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Note added at 2 hrs (2010-08-13 17:10:10 GMT)
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Perhaps the best answer would be 'almost exactly'.

I think you have a dictionary and can decide on the fundamental meaning of 'substancialmente.

Here are a few thoughts on the matter:

If two things are essentially the same thing then they are almost exact. There may be a few very fine details that differentiate these objects/items/people/etc... but they are as close to being exactly the same as is possible.

10 ago. 2010 ... In fact, the term hot tub and spa actually mean essentially/almost exactly the same thing to most people. But other commonly used names are whirlpool and ...
cwconnect.computerworld.com.br/.../what-you-should-know-before-you-buy-a-hot-tub-spa/

“Scott McNeely of Sun said essentially the same thing some years ago. He plays hockey and I've been waiting patiently to see if he's ever caught a puck in ...
www.huffingtonpost.com/.../eric-schmidt-privacy-stan_n_6772...

As you can see; 'essentially' as suggested by MC means 'almost exactly'. This isn't the wording that I would use, hence my original answer.