I feel like an idiot... How to create a face / side?

Dear All,
I am new to Sketchup… but over the past 2 weeks I have successfully created a model of my house and I am playing around with it. We are thinking about doing an extension.

However… I am find one thing in particular extremely challenging. It is simply the creation of a Face. Let me give you an example… Attached is a picture of the model - I am unable to get the a face created in the garden to then shade in green. I have gone around each of the edges and believe they all connect… but I cannot create the face.

And then when I draw lines across it… I can some of the face created but not all… but when I delete the lines - the face goes…

Can anyone help?



HI , to create a face all the edges have to be joined , co planer and without any edges protruding into the proposed face. Without having the file its hard to tell what your problem is. The triangles suggest that the edges are not co-planer . i would start again with the garden and erase the lines already draw, If you go to window>style>edit tab and select by axis with the drop down window at the bottom any off axis lines will show up black.


Hi Angus, I did a vid on a different subject ,but it shows what the “by axis” selection shows up


Apologies. I did not see your response - I thought I would be pinged an email when someone responded, assumed that no one had answered.

I could not access the video that you linked. I tried to recreate it, but not been successful. I have attached a copy of the file and I would appreciate you have a look. Overall happy to take any advice that you or others may have.

Thanks in advance

Extension v8 - Ready for Extension.skp (1.7 MB)

Hello Angus,

I’ve loaded your model, and what I found was that the base of your walls, and the hardscape and the grass along the wall are NOT co planar. My suggestion to you and anyone learning to use sketchup is to first start your model with a plane that has your plan applied as a texture, then scaled. Once you do this double click it and make it a group. Then you can build your model on top of it. This way your ground plane will remain a plane. I would delete the hardscape and grass that you have, and possibly the walls, select your entire model and group it. Then create a separate plane, and if you have a drawing apply it as a texture(don’t forget to group it), then put your model on top of it. If you don’t have a drawing to texture the ground plane with then just draw on top that way it will remain coplanar. Hope this helps.


Certainly, techniques for keeping drawn edges on plane are essential basic skills, but there is an elephant in the room that should perhaps be acknowledged. That is, you probably don’t want to construct your model as all raw geometry anyway. As it is, everything is touching everything else and everything is all stuck together, and tweaking one part of the model threatens to blow up something else. It’s like a house of cards. Your model should be more modular in its construction.

Using this approach, you would construct a lawn object as a group or component, block wall objects as one or more groups, a sidewalk object, a house object, and so on, with each major element of the model a group or component. By structuring your model this way, you can modify or repair or relocate one major element of the model without affecting other elements, since everything is no longer stuck to everything else, and objects can be edited at any time within their own, isolated context. It’s also easier to construct simple shapes to be coplanar in the first place than to construct complex shapes that way.

Notice that by using this approach, the lawn would be a separate object you could work on directly rather than a sort of by-product of the sidewalks and walls that is dependent on those other objects for its own integrity. That is, you could just create the lawn as a rectangle and take bites out of it to reduce it to the right size and shape and then move it into position, not necessarily in that order. That way, it would be a face from the outset, and if you did something to it so it would no longer support a face, you could just Undo out of it.


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Larry & Gully
Thanks for your advice. I have however some more questions.

Firstly, what is CoPlanar - I have googled it and looked at the help, but not any wiser. Can you kindly explain it to me as if I was a 2 year old… Apologies :wink: I not only have this issue in the garden, but also on the 2nd floor above the front side window.

Secondly… Fully appreciate your comment Gully. I think I was more focused on layers when creating it, vs grouping things. Have you got any advice on (1) how to fix hat I have done so far without creating it all again (2) what guidance do you have for grouping things in a house. On (2) for example… I get that it is best to group things like fridge, sink and other objects in a room - also I get grouping 1st floor vs 2nd floor and garage & garden… but should I be looking for any other grouping - for example - by room?

Many Thanks in advance!


Coplanar means “on the same plane.” In SU, to form a face, the bounding edges must all be on the same plane.

Do not assume layers in SU work the same or have the same characteristics as layers in other apps. You appear to have used layers where you should, in fact, have used groups and components.

Groups and components are used to isolate, protect, organize, and structure model elements. Layers are used for the single purpose of controlling visibility: on or off.

Before proceeding further, read and heed the following: Does SketchUp Support Layers?


Edit: Ah, and as to the logic behind groups and components generally, this is certainly subject to opinion, but in my opinion, a group is used to isolate and protect from unwanted interactions with other geometry any free-standing (or capable of free-standing), integral, co-functioning collection of geometric entities that will have the same visibility requirements. It is understood that two geometric entities in the same group making contact will be inextricably fused together.

A component is like a group with additional capabilities directed toward reuse and multiple use. I can see a wall group or component (all walls grouped together), and I can see a floor component, or a roof component, and of course doors and windows, but not really a room component, because a room seems to be not a component itself but a place where a bunch of components come together in a particular way, at least as I see it.


Many thanks for your answer. The world of gorups, components and layers is becoming clearer to me. Thanks

One further question if I may. I now understand what you mean by coplanar - however what still confuses me is an easy way to find out if it is on the same plane or not. I have tried a number of views, angles, zooming in etc… but not any wiser. Is there an idiots way of finding out?


I’m reluctant to admit knowledge of idiots’ methods.

The fact is, and not wishing to be facetious, If an outline looks clean and without breaks and a face still won’t form, you can pretty much assume it’s non-coplanar. There are only so many reasons why a face won’t form.

There are a couple of objective methods to see if the geometry is out-of-whack. First, you can turn on edge coloring by axis. Go to Style > Edit > Edge Settings (1st icon). At the bottom of the dialog is a control called Color. Pull down the list and select By Axis. This colors edges of the model the color of the axis to which they are parallel. If an edge is not parallel to any axis, it is left black. If you see any black edges, they are off-axis. If that isn’t deliberate, there’s your culprit.

Or, you can use the default text created by the Text tool when the leader is directed to a point–the point’s x,y,and z coordinates. If the face is supposed to be horizontal, look to see if any of the z values are different.

The following picture shows an object with a missing face. The outline of the missing face is clearly non-coplanar. On the left you see the object with Color by Axis turned on, and you can see that one edge of the missing face is on-axis and three are not. On the right you see the same object with the four endpoints labeled. The z values (third number) would be the same for all four points if the missing face were horizontal as intended; instead, they are different, so the thing is clearly out of whack.


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Hi All,
Just a quick note from me to thank you all for your help. It has been extremely useful. Many thanks

Apologies for the delay… nothing like 2 kids to keep me extremely busy.


The best way to ensure that everything in your model is coplanar where it needs to be, is to draw it that way. Daft as it sounds, while you’re drawing,make sure you use the inferencing engine: If you take the line tool and draw a vertical line, it will be blue… keep it blue. Then if you draw another line away from it on another axis, keep it on that axis… Then when you draw a line downwards again and you want it to be both vertical and the exact same length as the other vertical line, start drawing it so it’s blue, hold down SHIFT to lock it onto the blue direction… and then move your mouse so the cursor snaps to the bottom node of the first line.

Youre now guaranteed that these lines are the same length. If you push/pull the face you’ll eventually create by doing this, then its lines will be parallel. If you then want to draw another set of faces coming away from this (imagine we are putting the walls around the garden), you know that these faces were drawn vertical, and any pushpulls will be perpendicular, and the base and the wall faces will be co planar

If you’ve drawn two garden walls for either side of your plot and when you link the bottom corners, a face won’t form for the garden, then the walls are not co planar at the bottom.
Select the small bottom line of the wall, get the move tool and grab the selected line at the corner. Move it in the blue direction, hold shift, then point to the other wall, in the corner… I’ll do a video to show you what I mean

In the vid I draw 2 garden walls then make one of them deliberately wonky - obviously a face will not form… In sketchup a face won’t form even if the wall is 0.1mm wonky, and a simple slip of the mouse when you’re drawing, can put something off plane

So what we do is identify the points we need to be on a plane, and move them, aligning them relative to some other point that we know is on the plane we want to have… We end up with a wall that is still wonky in so many other planes, but they can all be fixed in the same way, or once you have the base of the wall sorted out, delete the rest of the wall and pull it up from the ground again

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Hi Gully,

In your example drawing you have a dark grey face that is not coplanar. How did you accomplish that?


I will take a stab at this, as without quoting or referencing @Gully_Foyle he may never see your question on this 4 year old thread. I believe you are seeing the backside of the bottom wall or “floor” of that shape in dark grey, looking through the aperture of the missing “plane”. See the left hand example where the camera angle allows you to see the green on axis line of the far deep corner.

One could cover that non-coplanar space with many connected triangles, a mesh, then use soften-smooth to blend the divisions giving the appearance of a connected surface, but by definition one cannot create a flat surface from 4 non-coplanar points, which was the point of the shape drawn in the example.