Function solid_scale 

pub fn solid_scale(solid: &BrepSolid) -> f64

solid_model_scale floored at 1.0 — the characteristic length KernelTolerances::for_solid and the boolean/imprint/heal sites are tuned against. The floor keeps a unit-and-below part on the historical bands those call sites were fitted to; new size-relative sites should prefer the unfloored model_scale family and floor explicitly where they mean to.