Model (and page) Scale?

We've established that entityTransform being managed by a DOMMatrix is a reasonable way to work on transforming the appearance of a model, but there's a mapping that we need establish between the real-world dimensions that are inside 3D models and the pixel- or point-based scale of a web page.

CSS dimensions technically do have cm (and inches, if you must) but we need to look at the perceptual appropriateness of leaning on them, based on where browsers with a more complicated relationship with scale end up. (both Quest and visionOS, through various user operations, can end up with very different perceptual scale to the logical "points" or "pixels" recorded for a window)

This isn't to get spatially-correct dimensions for any particular context, as the window metrics should be the main determinant for this - but I wanted to check in on what is a reasonable place to put some scale factor.

/agenda

No files or tests are named; start by reviewing the entityTransform/DOMMatrix discussion and the CSS cm and inch behavior across Quest and visionOS. Done means agreeing where a scale factor belongs and documenting a perceptually reasonable approach without requiring spatially correct dimensions.