Can't separate face from window in house

I’ve created a super detailed to-scale model of my house as part of a neighborhood 3D master plan I’m working on with our community development group using SketchUp Pro 2018. This was my first super detailed model and I likely did every step of the modeling inefficiently (for example, I literally hand drew every one of the bricks, which took DAYS).

The model is nearly complete and I’m working on cleaning it up to export in STL to 3D print.

I’ve found a problem where the window on the left side of the house closest to the back is somehow inseparable from the face/wall/morter between the brick. I can’t select and deleted the layer covering the window without deleting all of the space between the bricks too - see screenshots below.

I spent about 4 hours last night doing everything I could think of to fix this. I tried redrawing the outline of the window, redrawing the curved top of the window (and now somehow I can’t get it to match the other windows), I tried redrawing all of the bricks directly around the window, etc. etc. etc).

Can anyone tell me what I’m doing wrong here?

Ultimately I am trying to prepare the model for 3D printing in accordance with this guide:

I believe that this window layer problem is a problem for the outer shell function. That said, I think it is a problem for the model whether it’s being 3D printed or not.

I’m attaching the model itself in case anyone wants to mess around with it here:

(I can’t see if the file uploaded in the preview - might be too big, so I’m uploading it via drive at this link: )

Would love some guidance here and please feel free to share some 3D printing tips if you have any. I’m attempting to print via the New Matter MOD-t 3D printer (

There are quite a few issues that will make your model fail to 3D print.

For starters, you have several levels of nested groups. SketchUp will never consider such a nest to be a “solid” and many 3D print systems will also reject it.

You also have a great many reversed faces. I set the back face color to an annoying green and then activated monochrome style and got this:

3D print (and rendering) software generally uses the front/back face orientation to decide what is inside vs outside your object, so all those reversals will almost surely cause failure.

You have drawn the model full size (which is generally the right thing to do in SketchUp), so you will have to scale it down before export so that it will fit into the print volume of your target printer. That begs questions that depend on the printer you will use: how many of those small details will be useful at the scale you can actually print? Will supports be needed to prevent small details from collapsing?

In the area of that specific window, you have faces co-located that are confusing the issue. Have a look at the sill in this image - you can see the characteristic “shimmer” effect of z-fighting from two faces at the same location. You can also see that the window opening and all the mortar lines are parts of the same face (see how the selection has caused all of them to be stippled). This particular window opening is not cutting through the face of the wall and can’t be deleted without taking the rest with it.

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Hi ty, I have had this, or a very similar issue, a few time too. In addition to the problems that slbaumgartner pointed out concerning the 3D printing, In some of my cases it has been as simple as having an extra face against the wall covering the window that is stubborn to delete. I have sometimes found the root cause to be a plane that is ever-so-slightly out of axis. I know it sounds like more work than it is but you may want to try deleting that whole section of wall and rebuilding it, making sure that everything is square and on axis…here’s hoping I can be of help…BTW, that’s a nice looking model. Mick C

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One dumb observation: The zillion bricks you have modelled would probably not show in your 3D printed model, as they are coplanar with the mortar. For them to show you would have to push the mortar parts in a bit, createng an insane amount of new geometry that would still require an ultra-accurate printer to show.


Makes sense slbaumgarter and thank you for the observations, but how do I fix the problems without restarting from scratch?

The digital version was important to have accurate in and of itself. Every detail doesn’t have to print on a 3D printer, but I’m hoping I can use the same model for the digital version as I have for the 3D printed version, or at least not have to do 2 completely separate models of the same house for each application from scratch each time kind of thing

I was just implying that using a brick texture instead of splitting your wall into a multitude of faces would make your model easier to manage.

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Do you have any recommendations for how to do that attractively and professionally? The built in brick textures don’t meet the caliber of aesthetic that is required for this masterplan to carry weight with the city planning department lol.

Have spent the last two hours reversing all of the off faces. I still can’t figure out a solution to that window/face thing from before though.15 PM

I hope you put a green color on the front surface, not the back, because otherwise you now have all faces in the model reversed! You could fix that by selecting everything in the model and then right-click reversing faces.

I fiddled a bit with that window and I’m finding that for some reason there are edges there that don’t properly cut the adjacent faces. Typically the ends of mortar lines where they meet the window opening, but also random other places in the model. You can see these if you increase the profile width in the style, as in this image.

14 PM

This is probably a result of the way you drew them, but I can’t find a specific flaw such as out-of-plane and attempting to fix them by redrawing has been hit-or-miss.

I think I found the origin of the problem: there are some very tiny edges (about .007" long) where the mortar meets the window outline. They are so small they are confusing SketchUp’s decision about whether the face is split or not!

05 PM

I suspect these came about because the bricks in the surround of the window are not perfectly aligned with those on the wall face:

23 PM

Also, this particular window was set flush with the face of the wall (which causes the z-fighting) whereas the others were set a bit proud of the wall:

At this point, since the geometry has run together, it may be a tedious mess to set this right. So far I haven’t succeeded. Perhaps one of the other gurus has an idea?

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Here’s the most up-to-date file that I’ve got. I can’t even get the thing on top of the window to go away anymore. I don’t know what I did

I’d be inclined to cut away a large chunk of the wall and rebuild it without all the time geometry.

I do have to wonder if all the “super detail” you’ve created will be printable when you finally have a solid. At what scale are you planning to print your house?

Right now I’ve deleted the whole mortar area, but can’t for the life of my figure out how to select the rectangle below the window or the rectangle outlining the window - see screenshot:

54 PM

It’s like grayed out and unclickable. I’ve selected all and exploded everything as well, but no luck.

I’m printing on the MOD-t 3D printer which has the following max print dimensions:

19 PM

I’m still figuring out the kinks in operating the printer, but it actually seems to be able to figure out all of the face directions on its own. Here’s a screenshot of what the STL file looks like in the MOD-t viewer:

I’m having to 3D print lock bars right now to secure the print plate to the rollers (30 more minutes), so I won’t know how well this will print until that point.

I actually did send the STL file to the folks at New Matter and asked if there were any glaring problems. The gentleman I spoke with this morning said it looked like it would print fine (though he may have given me some bad advice on something else, so I asked what seems like the more knowledgable woman - even though she has less experience - for her advice - waiting on a review now).

For what it’s worth, here’s the STL file in case you’re interested / know how to view STL files (i sure don’t):

Based on the icon view my comp gives me of the STL file vs. what New Matter shows, New Matter must be really good at piecing stuff together cause it looks like a failed Porygon (pokemon reference) on my comp, but looks like the house when uploaded into my New Matter library

Here’s a fixed portion of the house. I got most of it done with the move tool, converging vertices.
The arch at the top of the window seemed to cause most of the trouble. There are likely other issues but I’ve run out of motivation.

Fixed Window.skp (553.6 KB)


You rock. Just cleared all the old stuff out in that section and edit-copy-pasted it into the existing model. It worked perfectly! Thank you very much! Here’s the link to the current model - just working on reversing the last few hundred bricks on the backside:

Just wanted to share with everyone that the model printed and it was a success!!! Note the detail in the stonework and front door (spaces that were just inches in real life that somehow turned out despite being reduced to a fraction of the size.).

Here are the overall dimensions of the structure in the real world and the size the 3D printer shrunk it to:

I used Sketch Up for 99% of the work and then imported it into AutoCad’s Print Studio (free) and clicked the “fix all problems” button and ended up with this file:

Here’s some photos of the final product:


Awesome cooperation from the community. So impressive!

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