下句（见补充说明）是否为同位语从句?

下句（见补充说明）是否为同位语从句?
In a number of museums,one of the rooms is designed so that its walls (from head-level up) and ceiling make up half of an ellipsoid(椭圆体).
不可能是目的状语从句，因为原句后面还拖了一个表目的的不定式：........,to make the walls smooth and streamlined.
只不过我在摘抄时为了突出问题主干把它删了。