Import DWG problem with surfaces

Good morning,

I have Sketchup Pro 2018 for Windows and when I import the dwg (for example a plant of a house) I explode the plan, then I create a flat surface underneath, but not all the areas become closed surfaces.

So in the end I still have to go over most of the design.

What can I do?

I attach photo, here:


I’m pretty sure that this is normal behaviour. I’m always inserting DWGs and have to do exactly the same thing to close faces.

Saying that, I normally create a copy of the DWG Component before exploding the one I use.

It’s a pain but I think it’s just one of those things.

Kind regards


The problem with many DWG files is that they are generated as 2D graphics (or at least, with that mind set), and the whole notion of faces isn’t important. Also, ACAD makes curves that are “real” curves, but are represented on screen by straight line segments. You may find filets and rounded corners with a bazillion tiny segments that touch, but are not “joined” as we like to see in SU. You sure can trace these areas or delete them and add SU arcs … OR you could use one of the “weld” plugins that join unruly orphan lines, which will create an area that can be made into a face. Another problem with ACAD .dwg files is when it began to truly implement 3D, some many years ago, a lot of drafters didn’t “get” it and ignored the Z component of an object’s location. They would blithely continue on with lines all over the place vertically, because the 2D projection looked fine. Some of those ill-trained drafters wound up making component drawings for industry and you will find these horrible models all over the internet. It’s kind of too bad the manufacturers don’t hire SU experts to make decent 3D models of their products.

dont know what version of sketchup you are using, but if its one that can run plugins, there is a “make face” plugin, that usually does a good job of making faces when there aren’t any, even if they are closed loops.

Ditto to all of the issues, and solutions so far.

  Because there can be so many misalignments - as well as a million

extraneous lines that could be anywhere, my first action is to set
my view to parallel projection with front view, get as close to
the lines I need, select and delete above but usually mostly
below. Then see how much of the drawing I loose, and work back
from there trial and error. At least from then on I shouldn’t be
driven nuts trying to join lines that create non planar surfaces -
or are on different planes.

  The same type of issue arises when importing SVG. While the z

axis is ok, line segment length appears to have a correlation to
the total line length, which is really frustrating and
necessitates a a lot of tidying up of curves in particular. Having
some control over the line segment size on import would be a big

Some other method would be to bnb use Eneroths flatten to plane which will put everything on one level plane. You could then use edge tools to find gaps and fill them…then run make face?

hello, what are the name of these plugins?

hello, what is the name of this plugin?

make face is a plug in?

Yes MakeFaces is a SU plug-in/extension. (Todd Burch/

“S4U make face” is its name.

not a great video but shows the principle, it saves re-traces edges.


Erika Pigni

Note: I’d always used the “s4umake face plugin” but as its now a paid extension, the one @Charlie_v mentions from Smustard might be the better choice?
You can drop the .rb directly into the plugins folder ( it needs the progress bar plugin too) and restart.

the s4u has an icon you put in the toolbars and the other is available through tools dropdown.

Hi, Erik.
As you can see, there are several. The one that came to mind (and one I use now and then) is one called “Weld” by Rick Wilson. With it, though, you must be careful, as it will weld edges that are not on the same plane. I seem to recall at least one other Weld utility, but I don’t remember its name.
The weld I use (Smustard) makes an entity that SU calls a curve, and is for all intents and purposes identical to what AutoCAD calls a 3Dpolyline. If that is cumbersome, you can explode it without losing the faces it will contain.
(in my version of Smustard Weld, it claims to make faces, but does not…I have to do that manually. Not a big deal; I made a keyboard shortcut to create faces from selected (and joined) edges.

How much does it cost?

Do you suggest yours plug in or s4u Make Face?

I’m a cheapskate. Unless I can’t find something that does the job for free, I don’t pay anything. I do, however, give credit, and thanks, whenever possible.
Realize that I began doing this stuff when the only tools available were T-square, compass. triangles, and pencils. I was overjoyed when they came out with parallel bars. And I embraced digital drafting when it finally became available for those of us with 8088 processors and monochrome displays.
Yet, I’m not entirely adverse to using software right “out of the box” and native tools. SketchUp is amazingly robust, despite its flaws, and there is usually a way to accomplish anything you desire.

Smustard Weld is useful, but if it were to suddenly vanish, I’d still be able to create in SketchUp. It didn’t cost me a dime.

Erik, go to the Extensions Warehouse and spend an hour browsing what’s available there. It won’t be time wasted.


Erika Pigni