Top or sop outline drawing problem

I’m trying to trace the outlines of a top to draw them gradually
The same happend starting from a sop…
If there are holes in the form they get connected to the exterior line.
Like a one line sequence of points, and the result is that in the render came many unwanted lines.
I was thinking to animate them with a line and a ramp. Sure there are many ways for achieve that effect. But is not that.
How to achieve oulines and inlines as separated groups without merging many many separated forms and operators?
Imagine a facade full of windows for example…
Thanks a lot