ΔE 13.9, fair: the same colour family, but not a straight swap. Rust Orange is a little lighter, more saturated than Ruddy Terra.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Rust Orange is a little lighter, more saturated than Ruddy Terra.
The same difference applies the other way round: Ruddy Terra is a little darker, more muted.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Ruddy Terra on the colour wheel See Rust Orange on the colour wheel
All matches: Ruddy Terra equivalents · Rust Orange equivalents