Making the ground

10am Mon 16.skp (6.9 MB)

I am very new at this but I am trying to make the ground around my building for a uni assignment.

I drew a big rectangle for the line work to sit on. Then a smaller rectangle to mark the “edges” of my model. So technically there should be 2 things for it to sit on.

I have drawn in most of the roads and a railway track

The top left hand corner of my wont form a bounded shape.
The roads are clearly forming bounded shapes (hence the blue traffic islands)

But I can’t add a texture to the roads and I cant make the top left hand corner so that I can add textures etc.

Any suggestions on what I am doing wrong or how to fix whatever isnt working? I have started again with the ground 3 times now. This is the closest I have gotten to getting it right.

Thanks in advance.

If you’re new to SketchUp be sure to check out our Fundamentals Course over at SketchUp Campus -

Also, since you’re working on a large site design project, you’ll find some good info in our Landscape Track…more specifically the lessons on cleaning up linework and making faces -, and subsequently, the next lesson on working with groups -

Now to answer your question:

I started by grouping and moving the inside of the road (median, etc) outside of the site so that I can deal with just bounding edges only. They may be hard to see but look close and you can see some stray edges and edge gaps. When you’re manually drawing multiple lines on top of other lines and surfaces that are ungrouped, this invites the possibility for duplicate, stray or edges that may look like they form a closed boundary but are not touching.

Here I erased any stray lines, erased and re-drew the bounding edges along the perimeter, and the face filled in automatically…

Next I moved the medians, etc group back over (could have done it without moving but wanted you to see the edge gaps, etc that were otherwise hidden. Then I exploded the group so the faces merged with the larger road surface.

Finished by assigning some color. At this point I would group-by-material and assign each material group to their own respective tag (re: the Campus lesson I recommended). Good luck!

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You also need to change to a style that has a background that is visually different to the front faces.
If you look here you see all the green parts in the version on the left are Holes.

The railway is a real issue too, all those edges sticking out will stop a face forming in that area. Make the track a separate group and place it on the terrain. Same with the building underneath, it should be grouped separately.

Basically, stray edges and overlapping curves are your main issues.
Here is an example of how a stray edge stops a face forming.
Stray edge

Two issues with this, in this case the large rectangle has no face, and if done incorrectly you could end up with two faces not intersecting or not flat which would create another whole set of issues.

I am pretty close. I realised the railway was an issue. I have deleted it (the railway) and fixed up all the broken edges.

I watched the links you posted.

Now my problem is - how do I make the road traffic island bit sit on top of the road bit - when I try and put it over the road - the 2 surfaces sort of fight each other (I think I read someone calling it z-fighting)

Also - I understand each of the words in this sentence…but have no idea what the sentence means.
" change to a style that has a background that is visually different to the front faces."

Any suggestions?

You may have missed this bit.


Yes you are correct - I did that and now it looks great. Thankyou so much for your help.
I am a computer technician studying a Bachelor of Construction Management. I have been using forums for computer stuff for years and have never known a forum to respond so quickly as I have with the sketchup forums. I am blown away.

Again thanks for your help.


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1121am Mon 16.skp (7.1 MB)

Fixed the landscape - now I just need to design the 2 above ground floors and make it structurally sound and do a cost analysis on the whole thing.

Piece of cake?

You should look at face orientation, white faces are the front face when viewed in Monochrome mode, a lot of your ground is reversed. This is hidden by the materials and may not be seen as important but it can cause problems down the line. Sketchup and various other tools use the front and back to understand what is happening, many render engines will ignore back faces so you render ends up with black sections. 3d printing need the faces to tell it what is material and what is space etc, so it is best to keep on top of face orientation.

I would also carefully select all the parts of the ‘ground’, avoiding the basement structure and make that a group. This will stop it interacting with the basement and your upper floors. You can also tag it to make it quick to hide when you want to work on the basement.