Femap is "unitless" - but this means you must use a consistent set of units. eg. SI = N, m, kg, Pa. Most engineers prefer mm. If you also prefer to use N, then your consistent set of units would be N, mm, mm/sec2 (for accel), MPa, and tonnes (because F=ma). Thus, if you prefer to use N and mm, then material density must be in Tonnes/mm3. For example, steel would be 7.8e-9. SolidEdge might be using something different.
It might seem a little inconveneient, but it is simple once you know what you normally use. And I have repeatedly seen systems that claim to look after all of this for you to get it wrong once it comes to FEA!