Density Box takes too long to load
 

Hello, I am a beginner to CFD, and I am meshing a model of a UAV in ICEM for a project. I am required to perform the CFD analysis to determine the L/D ration and relative parameters. The simulation is for a Laminar flow of the Re = 1000, and I am looking to perform a viscous unstructured meshing of the model.

I was advised to do the meshing in ICEM and solving in Fluent. I haven't used ICEM previously, but I am learning on the various features and processes. I am able to generate a coarse unstructured mesh (Eulerian), but not a viscous one, as I did not refine the Boundary Layer mesh.

I came to know in order to do a refinement I must use a "Density Box" in ICEM. So when I tried using the Box for my UAV in order to refine the BL, the process keeps loading for hours just as I select the model for the box, I haven't hit use entity yet.
Is it because of the geometry or am I doing something incorrect?
Thanks in advance.

https://imgur.com/a/ZkBfj8I (What I have currently)
https://imgur.com/a/oEKPgpS (What I need)
https://imgur.com/a/1fueEMo (What I am stuck on)