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Method 2 - Optimizing CAD File Prior to SketchUp
Join / Close Linework

3.5_Join-Close Linework

0:01 As hard as we try to draft cleanly in CAD, the reality is, there will always be small gaps or overlaps in your linework.

0:09 This is especially true if you work as a team and multiple people are in and out of drawings.

0:15 It’s hard to control the drafting standards of everyone in an office.

0:19 But knowing that, there are a few easy ways to check to be sure that lines touch or intersect where they’re supposed to.

0:27 Let’s start by isolating some linework so we can focus on just parts of the plan at any given time.

0:34 I’ll select and use the 'LAYISO' command to show just the now consolidated interior wall linework.

0:42 I’ll zoom into an area that I’ve intentionally drafted poorly for this demo.

0:47 Here I’ve got two corners where wall lines converge at 90 degree angles.

0:53 After zooming way in, I can see that that I have both a gap at the corner, and an overlap.

0:59 Two common things that occur in CAD that make it hard to close boundaries and make surfaces later in SketchUp.

1:06 This is especially true with curves which we’ll deal with in a separate demo given that our floor plan is mostly right angles.

1:14 These gaps and overlaps can be an easy fix though.

1:18 I’ll start by using the 'PEDIT' command to convert the lines into polylines if they aren’t already.

1:25 Then choose ‘multiple’...

1:27 Then select all the lines that should connect to form a closed boundary...

1:33 Enter ‘J’ for Join and ‘0’ for the distance.

1:38 I can see now by selecting it that the wall is made up of separate polylines.

1:43 . If I didn’t know where the problem corners were, this would tell me.


1:49 I can now use the 'TRIM' to remove any line extensions or 'FILLET' to join corners.

1:58 Also, even if a line looks like it forms a closed boundary, it might not actually be closed.

2:05 I can check to see if my boundaries are closed by selecting one first, then checking in the ‘Properties’ window to see if the 'Closed' option is checked.

2:15 If it's showing as 'not closed', it could be an indicator that there’s something wrong, like a gap or overlap that needs correcting.

2:26 Let’s now look at what happens with curved lines given that it’s a bit different than straight edges and corners.

2:34 This quick demo wasn’t provided with your exercise files so just follow along for a minute.

2:41 I’ll start by importing this arc with lines intersecting it from both the inside and outside of its curve to see how it handles in SketchUp.

2:52 After successful import, I’ll explode everything…

2:58 then run the ‘Face Creator’ extension…

3:01 and see that all of the inside boundaries made faces but not the outside ones.

3:08 If we zoom way in to where the lines intersect with the curve, we can see that the arc segments created overlaps for the inside lines and left gaps for the outside ones.

3:23 This is because of the way SketchUp segments arcs using only straight lines. In CAD, arcs are vector-based.

3:31 This means that even though our lines actually touched the curves in CAD, they may not in SketchUp depending on how many and where the segmentation occurs.

3:43 One way to fix this in CAD (if we choose to) is to break the arc at the intersection with the lines.

3:50 If you have a lot of arc intersections or tangents then this may be inefficient and might be better to see how SketchUp’s extensions, such as 'Edge Tools' work to fix…

4:02 But it’s a good thing to keep in mind while you’re drafting as it’s much easier to do as you go, versus coming back in at the end and breaking everything at their intersections.

4:20 Now we let’s import that same curve CAD file in again…this time having broken the curve at the intersections…

4:29 …explode it…

4:35 make faces…and see that that they all close and make faces nicely without the use of any extensions.

4:44 As mentioned, there are extensions in SketchUp that can help find and fix small gaps and overlaps but we’re trying to be proactive and catch as much as we can upfront, while drafting...