PC Advanced SI

U

Umbrella

Refugee
Hi,

I am quite familiar with the SI system, at least for fully supported blocks. What I would like is a general formula for partially supported blocks.

I ran a quick experiment with the following structure:

..W

HU

HU

HU

V

V

BBBB

Where

- B: bedrock

- V: vertically supported

- H: vertically supported, supporting horizonal weight

- U: partially supported

- W: extra weight

- . (dot): empty, just a way to align (my spaces are eaten by the message formatter)

In my test, all blocks are wood frame

When there is 2 layers of HU, the maximum mass of U+W is 16 (unit:wood frames). This matches the 2 vertically supported H-faces with 8 glue each (unit:wood frames).

When there is 3 layers of HU, I managed to put a mass of 50 wood frames without collapse. I did not go to the max. This does not match either computation:

- 3 vertically supported H-faces with 8 glue each -> 24

- 3 H-faces + 2 intermediate faces between the U -> 40

A possibility would be 3 H-faces + 3 U-faces -> 48, but the U/W face was not accounted for with 2 layers.

I plan to run more test, but does anyone knows the maths of advanced SI ?

Thank you !

 
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A few more details

Using 1 or 2 HU layers lead respectively to the expected maximum mass of 8 and 16 (wood frames), matching the 1 or 2 supported faces of H. With 3 layers of HU, things get a little strange:

- When the extra mass W only spans on one column (the one of U), I was able to put over 130 frames without collapse. It seems like vertical stability becomes infinite with only 3 partial supports. (TODO: is it the nb of block or of faces that matter ?)

- When the extra mass spans on multiple columns (I tested 2 and 5), then the maximum mass above U is 25 wood frames, including U, and it collapses at 26. This matches the computation "3*H-faces - 3 * U-blocks" = 28-3 = 25.

 
Last edited by a moderator:
A few more details
Using 1 or 2 HU layers lead respectively to the expected maximum mass of 8 and 16 (wood frames), matching the 1 or 2 supported faces of H. With 3 layers of HU, things get a little strange:

- When the extra mass W only spans on one column (the one of U), I was able to put over 130 frames without collapse. It seems like vertical stability becomes infinite with only 3 partial supports. (TODO: is it the nb of block or of faces that matter ?)

- When the extra mass spans on multiple columns (I tested 2 and 5), then the maximum mass above U is 25 wood frames, including U, and it collapses at 26. This matches the computation "3*H-faces - 3 * U-blocks" = 28-3 = 25.
Click to expand...
wait, what? that sounds nuts. do you have a picture of this in action?

 
No sorry, but its really easy to reproduce in creative. I can make a few screenshots though. I guess the "nuts" part is the infinite stability with 3 partial support ?

This makes me think:

1) I always had the feeling that underground SI was stronger than just "wgt - glue". An underground cave with enough blocks above still allow a large weight to be supported on the surface.

2) Having infinite vertical stability is not great by itself, it is great because you can attach weight to it. But in my test, the attachable weight is not the usual glue of a vertically supported face (as shown when using multiple columns). I still need to understand the formula, but maybe we are not gaining that much horizontal support.

Also thank you for your participation, I was starting to feel lonely on this post :)

 
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