how do i create "outline" like picture

[tinaxtreme22]

The windows & Doors. how would i make the light blue around the dark blue? 

[Kurt Gold]

There are many ways to do that. What did you try so far in order to get the desired result?

Which version of Illustrator are you using, by the way?

[tinaxtreme22]

 i have tried adding a stroke and adding different effects. the picture you linked is helpful tho. i am using illustrator 19 i beleive. not the latest version but the one before that..

[Kaem]

[tinaxtreme22]

hi, i have tried adding a stroke and adding different effects. the picture you linked is helpful tho. i am using illustrator 19 i beleive. not the latest version but the one before that...

[Monika Gause]

I would use the opo plugin. http://63mutants.com/subc/products/opo_m01/opo_m01.php

Or this method if you prefer not to install plugins: https://www.vektorgarten.de/long-shadows-with-illustrator.html

This assumes that you want to be able to use the result for cutting. If you want to just export it to pixels afterwards and never intend to export vector files, then there are other methods as well using blends or the transform effect. Those methods will create a gazillion vector paths.

[Khazali]

If someone's still trying to find something without the use of a plugin, I've figured out a way. 

Use the "Blend" option to create the illusion of a long shadow between the two objects, expand it, and ungroup it all. Now the lines between will have a bunch of vector points as mentioned above by Monika, which will be a problem unless you're planning to rasterize it anyway. 

Select the "shadow" part of the object by either removing the top part and shapebuilding the long shadow or using the several pathfinder options. Select the "smoothing" option under Object > Path > Smooth. The smooth option only needs approx. 1 - 5% to remove the millions of vector points without rounding out sharp corners.

[Monika Gause]

I posted a link to a method that works without plugins and also without creating all those points that you then need to delete.