• Hjalmar
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    2 months ago

    Only the transformations one is correct. All the other ones seemingly also preform a translation, and even if they might be correct if you take the orgin to be slightly outside of the shape but that’s bad for educational purposes. Also this one makes the translation transformation look like the identity transformation.

    This last one might just be me, but shouldn’t shearing be included here?

    • barsoap@lemm.ee
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      2 months ago

      Congratulations, you found a complicated way to misunderstand a simple presentation. Then:

      All the other ones seemingly also preform a translation
      Also this one makes the translation transformation look like the identity transformation.

      You’re contradicting yourself there. Either each of the panels uses one coordinate system, in which case panel 3 is not the identity transformation, or the panels use two coordinate systems each, at which point scaling and rotation don’t include translation, and the translation panel uses the identity transformation.

      Or, you know, this is all not about teaching formulas, but words, and clarity of the rough idea, intuition, is more important than strict adherence to arbitrary things you just made up. I mean the axes aren’t even labelled why are you expecting the thing to be accurate. Who says this isn’t a log plot.

      This last one might just be me, but shouldn’t shearing be included here?

      Nope you’re right that’s the only proper critique to be had there. OTOH it says “most common” and if you don’t include perspective projection because you’re talking 2d only shearing isn’t that common at all.