Can't draw a rectangle through an existing drawing

I am a custom knife maker. I drew the blade for a folding knife that I intend to make and saved it as a template and also it saved to documents as a file.

When I open the template or open it up from documents I now want to sketch in the scale that the knife blade sits in.

If I select rectangle for a start and I want it to be outside the actual shape of the blade nothing happens, even if I select the pencil I can’t draw the rectangle. Either instrument only works if I actually work inside the drawing of the blade.

I need to superimpose a drawing on top of a drawing. Any help would be appreciated.

This is my blade:

Friction folder #212.skp (57.5 KB)

I would like to make a sketch of the blade sitting in the scale.

I don’t quite understand what you need, but I tested drawing a shape, both outside the knife and on the knife and it works fine.
Friction folder #212.skp (58.7 KB)

I’m not sure why you made a template for an individual design, but that’s neither here nor there, I suppose.

I think you need to adjust your thinking about how to proceed. Don’t think of this as making a drawing, but as actually building a knife, piece-by-piece. If there is a mechanism consisting of several small pieces assembled together, model each, individual piece separately, make them groups or components, and then assemble them together.

So model each piece part as they will be fabricated in as convenient and accessible a location and orientation as possible. Then simply snap them together into the completed knife model.

Like @quantj, I’m not understanding your exact problem, so please be sure to describe your objective and your problem in clear objective terms so we can help you more effectively.


If you select the blade does its edges turn blue being highlighted?? If you grouped or made it a component you need to open it for the rectangle to show on it. I have stumped myself before “nesting” a group in a component, or inside of another group and could not get the tool I chose to function. This is my guest and ONLY that. Select it and double click it…also using the Outliner drop down from Windows helps keep track of this for you till you get comfortable. YES IT IS confusing but it took me 3 months and I still scratch my head constantly. I did not think I would get it but if your making mistakes you are trying and it will and does get easy(ER)stay with it as mistakes are progress!!


I won’t know the actual size and shape of the scale until I can superimpose it over the blade so to speak. I can then adjust it (hopefully to fit my blade design. This is a quick sketch of a scale and i might add not to the scale in inches that I will need.

Knife scale.skp (46.4 KB)

I want to be able to draw this around the blade as I won’t know the actual dimensions until I see that it will fit.

You mention constructing each piece separately and then superimposing them…how do you accomplish this?

Fine, but as I said, your mind is stuck in two dimensions. You can model the pieces to fit the blade, just as if you were hand crafting it in the real world, holding each piece up to the blade and making slight adjustments as you go.

I don’t know what to do with this question. Are you asking how to make and edit a group? That is documented extensively in the Knowledge Base, which you must read. How do you accomplish what? How to move things? How to snap parts together, point on mating point? These questions are all general “how does SU work?” questions, and they are much broader than your model of a knife. You can’t just get quick answers that apply only to the knife. You must systematically teach yourself the general procedures that apply to all well-constructed models.

You keep saying “superimpose,” not me. That implies two objects occupying the same space, which I think would be indicative of an error in geometry. You’re simply putting the parts together, just as you would in the real world.

Please make your questions specific and detailed. I don’t know what it is about assembling the knife from pieces that you need explained, unless, of course, you don’t know how to use he Move tool. If that’s the case, you need to go through the readings and tutorials about the Move tool: it’s not just a question about your knife.


I amit that I just installed the program and am an absolute newbie. I downloaded Sketchup For Dummies and manage to build the dog house.

Now back to my problem…I opened up the file that I saved showing the knife blade (I included this in my first thread).

As you suggested I moved the blade upwards to give me room to draw the scale below the blade BUT in the blank white space below nothing shows up when draw a rectangle although below on the lower left side it records the dimensions.

If I click on ‘edit’ I can delete the invisible rectangle. It’s same if I select the pencil and try to draw a line nothing visibly happens.

If I were to take either tool back up to the blade and work inside the drawing they both would function normally.
I apologize for my lack of experience and wish I had you sitting beside me.

Uh, what did you say was your gender?

All kidding aside. Try to ask a specific question. When we resolve that one, ask another. We’ll get you there, but we must take small steps to ensure we maintain good communication.


Here is my question:

As you suggested I moved the blade upwards to give me room to draw the scale below the blade BUT in the blank white space below nothing shows up when draw a rectangle although below on the lower left side it records the dimensions.

If I click on ‘edit’ I can delete the invisible rectangle. It’s same if I select the pencil and try to draw a line nothing visibly happens.

If I were to take either tool back up to the blade and work inside the drawing they both would function normally.

I just don’t know what you’re talking about. What blank white space? What invisible rectangle? Click on ‘edit’? Edit what? Is there a group you haven’t mentioned? Work inside the drawing? What drawing? I don’t know what you’re doing or trying to do.

Generally, you would model an individual part by drawing its outline on the ground plane and then push/pulling it to some height or thickness. You might feel more comfortable drawing a big rectangle on the ground plane and using its face as a drawing surface. On Face inferencing (blue dot) will keep the mouse pointer on that face as you draw.

You should pick a template that is not so disorienting. Try using one that has a visible ground plane and horizon, even though you’re working on a mechanical assembly, not a building. I find they make it much easier to keep my orientation, and the horizon, in particular, is an invaluable reference throughout the modeling process.

Incidentally, that wasn’t, in fact, a question, even though you said, “Here’s my question:” A question is the thing that ends in a question mark, is spoken with a rising inflection, and is designed to elicit a specific piece of information. An important characteristic of a question is that the individual to whom it is asked does not have to spend time figuring out what the question is, since it is already the actual question itself, not some rambling narrative from which the question must be inferred.


I am really sorry that I bothered you. I was a commercial pilot for 41 years and also a flight instructor.

I have often told students that there is no such thing as a stupid question only a stupid answer.

If you can, upload a screenshot or video of what you’re trying to do, and maybe then we can figure out what’s wrong.

I didn’t say anything about a stupid question. I didn’t say anything about anyone bothering anyone else. I said you didn’t ask a question. And that’s true.

So ask one.

@corcliff I agree with Gully’s perception that disorientation is a big part of your difficulty.

Here’s a revised copy of your model:
Friction Folder Rev1.skp (25.3 KB)

Therein I’ve set the Style (environment) to something more human friendly than nebulous white space.
I’ve also rotated and moved the geometry to lie flat on the Ground Plane and located at the Origin.
Give this a try. I believe you’ll find SketchUp makes more sense when it’s VFR.


Let’s start over again, enough apologies.

Here is what I want create in CAD:

My question:

What perspective and camera settings do I use?

Assuming you want this in 3D:
In SketchUp, you constantly move your camera angle, so it doesn’t really matter what perspective you’re using. Imagine someone hands you this knife, you’ll look at it and probably turn it over or open it. Same thing, you have to draw this knife like real life, with parts and thickness. if you wanted to show a cube, you wouldn’t just draw a square, you’d add the lines to show it’s depth.
I think you should first start by learning the basic modelling tools to be able to draw a 3d object. If you’re trying to shortcut to a 3d knife, it’s just not going to happen. You need to learn the basic before trying to model something like this.
If you just want 2D drawings like a plan and elevations in traditional Cad drawings, then you can just draw a rectangle first and draw your lines on it like a drawing on paper. But this isn’t what SketchUp is really for.

Model in Perspective with the default Camera Field Of View, 35°, just as in the revised model I shared earlier.
There, as in the real world, you see objects in normal perspective.
In the revised model we also have the sky, ground and horizon for reference in addition to the drawing axes.

You may find it helps if you try to forget you’re looking at a flat screen.
Think of the model space as if it were the real world in which you build a 3-dimensional model with the only two construction elements at hand, edges and faces.

By default, newly created edges exhibit sticky behavior, which is desirable up to a certain point.
Sooner than later that sticky behavior becomes a hindrance.

Notice that when I revised your model I made the geometry of the knife into a Group.
Making Groups or Components, aka grouping, separates the geometry into what one might call a container.
So contained, grouped geometry is isolated and no longer sticks to other geometry.

Grouping logical parts of the model as they’re built is fundamental to the process of modeling an assembly comprised of many individual parts, such as your folding knife.

This video presents the basics of modeling with Groups and Components

I’m certain you’ll benefit from watching the other SketchUp Toolbar Series Videos as well.

Hi Geo,

I really appreciate everyone’s help but at my stage is like an 747 airline pilot trying to teach a Cessna 150 pilot how to fly his aircraft.

This what I wanted to accomplish for the present and eureka I finally did it. With perseverance and much time maybe someday I will be able to post a 3D animated model but I’m not holding my breath.

My thanks to quantj as well. I was given the program as a gift and I will keep struggling.

Knife in scale.skp (31.7 KB)


I’d really like to make you a proper 3D model of your knife so you can see how much better it is than a 2D drawing, but I’m not sure I understand what I’m looking at.

If you’re interested, it would really help if you could you annotate your drawing, identifying the pieces and their nomenclature, and provide links to photos of a similar knife.


1 Like

Good to hear you’ll keep working at it, you’ll find it very rewarding as you learn more and more.