Yes, you can create the launcher you need.
Fist of all, my Ubuntu is in Spanish, so I will translate some words; I hope you understand me.
1.- Create a proper script that run the Bricscad script.
Open gedit and write this:
#!/bin/bash
cd <path_to_Bricscad_script>
sh .bricscad.sh
Save the file into your personal folder (/home/your_user_name) with the name .run_cad.sh (the fist dot hides the file, only if you want to hide it).
2.- Create the launcher.
For Unity: Press the Super key (that one it usually has the MS Windows logo) and write Main Menu (this is my translation from spanish). So, you will find a program to create launchers. Select a menu, for example Graphics, and then click on the New Item button. Select an aplication type, choose a name, an icon, a comment, and for the command option write sh .run_cad.sh.
3.- Create a Unity launcher (optional).
If you want an icon on the Unity launcher, look for your app using the dash, and then drag it and drop it over the Unity laucher.
Ariel