Can't seem to make ground level

I am a uni student doing a model for an assignment so my appologies if this is a stupid newbie error.

I have a building with 2 basement levels and a carpark and some roads around it.

I need to make a plane or “ground” for the carparking space lines and the road to sit on.

I deleted everything “not the building” and did a couple of large rectangles to make a surface

I have deleted and recreated the roads / carpark a few times now.

For the life of me I cant get the roads to sit on the plane or ground. I am trying to add textures so the road looks like road and the bits inbetween look like grass.

The bits outlined in blue should be able to have grass in the middle - but I cant get them to.

I have had huge amounts of trouble with all the “grass bits” but stuffing around with edges, making smaller and smaller triangles until it filled in correctly eventually did it - except one bit that for no reason I can figure out - wouldnt work for the first 20 tries - and then suddenly just worked without me doing anything.

Is there a plugin that will check your model for corrupt bits? If I zoom right in and make tiny triangles like I did with the other bits there are some bits where it just goes weird - like I cant select lines - lines I select diappear for no reason I can see - I make a line and it appear in a totally different spot - that kind of weird.

Any advice would be appreicated. Modfel included.

940 Sun 15.skp (6.6 MB)

pic with blue bits

You need to upload the drawing so we can see what is going on. It is not clear how you set about drawing the various shapes on the flat plane, for example.

I did upload the drawing. Its titled 940 Sun 15.skp in the original post

As for how I did it - I just made the plane the used the 2 point arc tool for most of it.

Sorry, so you did.

Well straightaway one can see that the patch of grass you highlight isn’t flat:

The other two corners correctly have the Z value as zero but the corner I have highlighted is 30cm above the ground plane!

FFS - it looks perfect on my screen.

How did you make it tell you that?

Thanks in advance.

If you select text and click on a point, it tells you the coordinates.

Here is something that makes the problem more obvious (the Z-fighting shows that I have created a surface on top of an existing one:

Here’s another one:

By starting with a flat plane and drawing onto it, you did exactly the right thing. But somehow, in the process of drawing those arcs, you didn’t manage to keep the points on the surface. Either that, or something you did subsequently moved them.

That last example does have a grass surface, which is plane but not horizontal. The giveaway is the heavy contour line. If it were flat, the contour line would be thin. By filling in all the small triangles, you were able to create an off-horizontal plane but not the horizontal one you intended.

My model does weird ■■■■ I dont understand all the time. Like when I was drawing in the roundabout - I drew the circle - then went to look underneath the “ground plane” - and for some reason it had made 2 bug extruded columns under the main building. They werent there before I made the circle and I didnt do anything on or under the building.

The trully frustrating thing is that I don’t know if its not working because I dont understand it - or if its not working because the program is glitching.

That bit you have selected in the pic above is the bit where I selected it like 20 times and it wouldnt work and then on the 21st time - even though I didnt do anything different than the first 20 - it just worked.

So now I have the lines sitting on the plane - but there must be 2 planes or something because its doing that Z-fighting thing.

I suspect the clue to this is the word “newbie” you used in your OP.

In this clip, I have done what I think you meant to do. As you can see, tool tips tell you when you are on a face, and other useful info, on the fly. When I close the area with the third arc, you can see the contours go fine and that is an indication that I have successfully created a bounded zone within the larger surface. That’s the thing to watch out for.

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I am surprised there isnt a "flatten to plane type tool around.

Whilst we’re here…another tip!

Outliner shows that you have carefully named the various groups and components in the model. But when you have so many repetitions, it gets hard to navigate. It might be an idea to put all the repeats inside another container so you can switch them off all together and collapse the list to see what you have more easily. It is often best to work on one element at a time, which can be done either by switching other things off or by working within a container and hiding everything else. That would probably eliminate inadvertent copying for example.

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There is but it may not quite do what you want.

Also, as a newbie, probably best to learn how to do things without artificial aids, dare I say?

Yeah I agree. I am trying to learn it properly without plugins etc.

The roads are sort of traced / recreated from a satelite photo of the actual site. I should probably learn how to import topographical information and then learn how to merge my “new” roads with the existing ones - but I dont have the time to learn all that and still get the assignment done before the due date.

The assignment is just for the building - but I am a bit of an overachiever and wanted it “placed” in its environment.

Understood. But is there a danger that you spend so much time on things peripheral to the assignment that you don’t allow time for the assignment itself? If you are new to all this, the building will surely present enough challenges of its own.

Having said that, careful drafting technique is as important in CAD as it is in manual drawing. It’s just that the things you have to be careful about may be a bit different. I suspect the biggest challenge when new to this is trying to run before one can walk.

Yeah this is the danger. I allowed 1 day to fix the “ground” and between you and one of the Sketchup people I have it 99% fixed - certainly good enough for the assignment. Its just a question of time management. Same with the building itself. I would love to be able to add in all the reinforcement to the concrete and produce a totally correct structural building down to all the bolts, electrical cables, plumbing etc but it wouldnt get me any extra marks and I dont have that kind of time. I am sure part of the assignment is them making you practice your time management skills.

The sketchup guy said some of my faces in the terrain are reversed but since it “looks” the way I want it - learining how to fix that will have to wait until after I am done with the assignment.

Thanks for your help. I really appreciate it.


Nice thing about CAD or especially modeling in SketchUp. You can add detail later, especially with the use of components and tags, and especially for things (like rebar) that no one needs to see for the conceptual drawings.

I’ve been doing a little model while they are remodeling my house (literally at the same time). I print different versions for the framer and electrician with the finishes stripped down, as well as a version for rendering (for my wife). It’s fun to work out the framing very carefully and see the carpenter just do what they want, just hope it’s the right size for the fixtures.

The balance between showing what is necessary and what is not is a fine one which we building designers have to make all the time. There is also a slight tendency for designers to think they know how things should be done, despite the fact that they may be trying to tell someone how to construct a roof (say) who has been doing it since before the designer was born!

In a commercial environment, there is also the balance between spending just enough time and effort to convey what is necessary and going beyond that and effectively wasting time (and possibly client’s money if they are paying by the hour). It’s not always easy!

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So true! Usually my work is showing the "general intent” of the plan, not telling pros how to do their job–while trying to leave a way forward, based on my experience. We start out with generalizations, then if we’re still on the job after construction starts, we may be laying out windows to the fraction of an inch, often in collaboration with a knowledgeable super. Thanks for the feedback. It’s not easy and we don’t mean to make unneeded work, but we need to do enough to avoid problems. We are busy as it is.