(2020-04-23, 15:02)Orion Pobursky Wrote: I think, and Roland can confirm, that LDCad keeps the full precision for each part's position and matrix in memory as long as the file is open. This practice makes sense to me since it will cut down on rounding errors while you are actively editing the model. Once you close the model, the full precision info is lost and LDCad has to rely on the precision written to the LDraw file itself.
Good, that's what I was guessing as well—that calculating from the coded values gives a different result than applying the series of mutations I make while editing.
As a follow-up, then, it seems I might be doing something backwards. When adding new parts to a rotated assembly, I first snap to grid and reset orientation of the new part (on the relative orientation of course), then move it into place using part snapping. I should probably snap to grid after moving the part into place, huh?