Fix vector normalization in JD#17938
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thinkyhead merged 4 commits intoMarlinFirmware:bugfix-2.0.xfrom May 11, 2020
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As far as I can see in the code, inverse_millimeters does not include extruder steps. Using inverse_millimeters to normalize unit_vec will therefore lead to incorrect results for non-travel moves and cause junction_cos_theta to be incorrect as well.
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Description
As far as I can see in the code,
block->millimetersand therebyinverse_millimetersdoes not include extruder steps (see this code). Usinginverse_millimetersto normalizeunit_vecwill therefore lead to incorrect results for non-travel moves and causejunction_cos_thetato be incorrect as well. This PR fixes that by correctly normalizingunit_vecin case the extruder moves.Note: I'm not too familiar with the Marlin codebase, so please have a good look at this to make sure I'm not missing something. If I'm wrong and
block->millimetersdoes include extruder steps, please let me know and I'll close this.Benefits
unit_vecwill actually be a unit vector after normalization.junction_cos_thetawill be correct for non-travel moves.Related Issues
Might affect #17920, because the incorrect normalization should result in a further reduced
limit_sqr. The effect might be too small to notice, though.