Create closed polylines with boundaries

- Let's start working on the walls.…I'll isolate the 2D wall layer by clicking on Lay Iso,…and then clicking on one of these walls, and pressing enter.…That isolates just that one layer.…I'll zoom in a little closer to the floor plan here.…Let's go over to the Layer Properties Manager,…and turn on the 3D wall layer, and set it current,…and then change its color from…the default white to let's say, red,…and now we're set up to create new objects on this 3D layer.…

Right now, the walls are separate line objects.…In preparation for a 3D model, ideally,…what you should do is create closed poly lines…that you can later extrude.…The easiest way to do that is to use the boundary command,…of course you could use the poly line command,…and manually trace over each vertex, but that's too tedious.…A better way is to use the boundary command,…which can output poly lines for you,…and the way that this tool works is you click on pick points…and then you pick an internal point within a closed area,…and Autocad will analyze the contents of the screen,…