Talk:Infusion Altar (Thaumcraft 4)

Do all blocks count for symmetry?

On the subject of decreasing instability, there are a few clarifications that I feel are required for this article. My understanding of the infusion altar has, prior to now, always been that only "infusion paraphernalia" are checked for symmetry: the infusion altar would completely ignore the placement of blocks like stone, grass, flowers, hoppers, non-stabilizer modded blocks, and so on. From my reading of this article, it would seem that every block within the altar's (fairly large) range is checked. Is literally every block checked, or is there a whitelist/blacklist involved? --73.225.234.34 00:59, 17 April 2020 (CEST)

Linear versus rotational symmetry

I'd like to call attention to the clarifying parenthetic expression, which I will quote here, regarding the definition of symmetry:

X and Z coordinates should have an opposite offset from the Runic Matrix, Y coordinate should be the same

While I certainly appreciate the attempt to clarify, I'm afraid that this leaves me with more questions than I had when I started. I understand that the Y coordinate must be the same in any symmetric pairing (meaning that we can ignore the Y offset when discussing pairings), but I have to question what it means for the X and Z coordinates to have an opposite offset from the matrix. (All coordinates I reference will be relative coordinates. If it helps your understanding, I'll propose a theoretical Runic Matrix whose absolute coordinates are x/z (0, 0): this way, "relative offset" coordinates are equal to absolute coordinates.)

I understand that a block at x/z (0, 5) would need a corresponding block at (0, -5). That's because -5 is the mathematical "opposite" of 5 (this also makes sense because this coincides with the definition of linear symmetry across the line z=0); however, I don't know about the "opposite" of a block that is offset on both axes. If a block is at (2,5), does it need one paired block at (-2,-5)? (Does this mean that 180-degree rotational symmetry is more important than linear symmetry along the coordinate axes?) Does it need two paired blocks at (-2, 5) and (2, -5)? Does it need three paired blocks: one for each of the listed coordinates? (This is distinct from the case where it needs two, because one block missing from a set of four would produce 50% more instability.) Or, am I reading this wrong, and it actually needs a paired block at (5, 2)?

Another way of asking these same questions is this: does the altar check for linear symmetry, rotational symmetry, or both? On linear symmetry, what are the lines it reflects across? (I assume it checks for symmetry across x=0 and z=0, but does it check for symmetry across, for example, x=z and x=-z?) On rotational symmetry, does the altar take 90-degree symmetry into account, only 180-degree symmetry, or neither? --73.225.234.34 00:59, 17 April 2020 (CEST)