# Offset from Exterior side of Wall

Hi all,

I am trying to place a room separation line at the offset of 1m from the exterior face of the wall (the wall is a series of wall and its continous from start to end).

Using this post: Wall location curve

I am able to get the line on the exterior face of the wall, However now I have 2 question, as you see in figure1- the new line is not always at the exterior side of the wall. (For quick look, all the connected lines are the location line at center of the wall while the unconnected lines are offset from the exterior wall.

Second, how can I change the new line geometry to the room separation line type.

It would be great if you can pointout whats I am missing.

Thanks folks.

Gosh that looks familiar! Glad to see others are benefiting!

A few back of my mind thoughts.

1. Get the normal for the exterior side of the wall and translate by direction and distance instead of just offsetting. This isn’t ideal as any curved curves (not straight curves? Sometimes the vocabulary stinks) elements will fail epically as they won’t grow/shrink radially.

2. Offset by + and - values. Get the distance from the wall location line to both offset lines and filter out the line with the shorter distance. This method isnt yet perfect as it creates twice the geometry initially (+ and - offset), and requires some slightly more advanced list filtering which can be difficult for inexperienced users. That said, I would likely go this route if I were on a deadline as I know it will work if I can manage the lacing/list management.

3. (I haven’t tried this but it may be the best option if it works) Thicken the outside face curves to create a series of polycurves, which can then be made into surfaces, and then join all the surfaces into a single ‘super surface’ and get its perimeter curves. Create a polycurve by the joined/grouped curves. There will be two - one for the exterior and one for the interior - create a surface from the curves and discard the surface with the lesser area. Get the curves for that surface and use it to create the lines. If this works it will have the added benefit of creating a closed perimeter so the room on the exterior will bind faster.

Out of curiosity: what is the end goal here after you make the room separation lines and (I assume) place the exterior room?

This is an ongoing problem which the Dynamo team has been notified of. But it isn’t on their priority list.

This may help though: http://dynamobim.org/forums/topic/offset-curve-not-consistent/