Creating complex shapes in 2D

shapes
2d
curves
bezier

#1

After I have learned a lot today (thanks to Box and all the others). I have another problem that I can’t resolve on my own.

I want to create a shape like the one below. But it shouldn’t be drawn “freehanded” because it’s never clean and precise. The question is, how can I create so many different curves and a few lines and put all the ending and starting points exactly together to have a closed shape ?

Thanks in advance…


#2

A mixture of arcs might do it, ensuring that the curve stays connected and smooth. To get that, check that each arc starts exactly at the end of the next by paying careful attention to inference End point, and where relevant watch out for the cyan-coloured ‘tangent’ indicator.

If you don’t want circular arcs in places, you could stretch some (using Scale tool).

Or download a Bezier tool plugin.


#3

Thank you John. But I have to be honest and say, I don’t understand almost nothing of what you’ve said… (like some strange language… :cold_sweat:)

But I will try to find out how to make that work what you said…


#4

Draw yourself a rectangle bigger than your shape, to keep your arcs all flat. Make it into a component so your arcs don’t stick to it.

Draw one arc (use keyboard letter ‘a’ to start it) inside the rectangle.

Click on its end, click a second time at the right distance away. Drag the mouse sideways until you see the arc turn cyan in colour - that means it is tangent (smoothly in line) with the previous arc.

Play around for a bit to see what I mean. Also, open the Instructor window in SU, and/or use the Help pages


#5

I tried something, see the attached skp. I imported the drawing as a texture on a flat surface, then used the line tool to draw around the shape, cutting across all curves. Then I replace the straight lines with an arc, that arced over the drawn curve.

I could have taken more time, but you’re welcome to do that!

curvedthing.skp (117.2 KB)


#6

Ok. Thanks a lot.

What just came to my mind… Is there maybe a way to perform some kind of morphing in sketchUp ?

What I mean is, first you draw a straight line. Then you pick a point (or three points to be precise) along that line and drag or pull to create an arc within that line. In fact, if the line would be long enough, one could create this complete shape out of just one line…


#7

Not with a straight line but you can use the Bezier curve tool or Fredo’s Bezier Spline extension.


#8

Dave !!! How did you do this ??? And you did it within 2-3 min !!! Bezier curve tool ??? Did you do that with that tool ??

But this looks exactly like my “hand drawing” at the top… Did you have a way to use it ???

I have to find these tools right away … Thanks !!!


#9

I used the Bezier Curve tool from Fredo’s Bezier Spline extension in the Sketchucation Extension Store to trace your image which I imported into SketchUp for the purpose.


#10

Both DaveR and colin will have used the Sketchup File menu File Import to bring your image into Sketchup, then drawn over it.


#11

Well now I get it !! I downloaded Fredo’s extensions… After a first look, I can say that now SketchUp starts to be fun !!! I was told it was… but up till now, not for me to be honest… It was like a battle between me and the software… I wanted one thing and Sketchup did its own stuff…

All of you guys (and Fredo’s extensions) are giving me my hope back !!!

Thanks…


#12

Here I am again…

And as always, it looks so much easier then it is in real life… :slight_smile: I’m still looking again and again at the pic Dave posted above…
And I’m spending hours and I can’t even manage the setup of the project correctly to start drawing the Bezier curves… :scream:

Maybe Dave or someone else can help … pleeeeaaassseeee …

So. Here’s what I did…

First I made a component (10 times bigger then I need it). Then I copied it and scaled it to 0.1 (as I’ve learned before, everything you draw on the first one copies to the second. I was hoping that it would smooth smaller mistakes drawn in the big one.)
Then I imported the dxf with the “hand-made” drawing and put it on the surface of the component.

Then it looked like this …

After that I started drawing the Beziers… (took me a hell of a lot time trying to do it as precise and as smooth as possible…)
But somehow I couldn’t make a closed 2D shape out of it…

Then I moved it away and rotated it to all sides and found out that one tiny little arch was on the blue axis… :angry:
So I’ve cut it out and fixed the missing part…

Now it looks like this…

And now I don’t know how to make it 3D… :sob:

(I was writing this post for about 3 hours. Step by step the way I was trying to put this thing together… so you can imagine in what state I’m in… :rage: … )


#13

Wow! That’s a lot of work and kind of in the wrong direction.

Where did you learn this? Doing this is likely to cause problems with some models unless you correct the component definition for the smaller component.

That wouldn’t smooth out mistakes, it just makes them look less obvious when you see the thing smaller. It’s like an Earl Scheib paint job on your car. Looks great at a distance but get in close and it looks like they painted it with a corn broom. :smiley:

I started by importing the JPG I saved from your original post. I made sure to import it as an image. I made it quite large–maybe about 24 inches tall. Then I started tracing it with the Bezier curve tool as I said before. There are a couple of tricks I used when drawing the Bezier curves. First, I didn’t try to draw the shape with a single curve. I split it into a bunch of shorter ones. Second, don’t try to get the curve to fit perfectly at first. Instead, get it in very quickly and roughly. After you’ve got it placed, you can move the control points and even add additional ones if you want. Adding control points is done by double clicking on the orange lines between control points.

Note: I did not make a component until after I finished drawing the shape and made it 3D. Once I was happy with the shape I deleted the image.


#14

Thanks Dave !

I saw already that it didn’t bring me anywhere so I deleted a couple hours of trying with a single click … :cry:

But as they say… Every end makes room for a new start…

Now I started from scratch… I’ll try to follow your steps now…

2 questions… Did you draw a rectangle first and put the image on top? And is there a way to make sure that all your curves are on the same axis? Sometimes some of mine (especially small ones jump to the blue axis)


#15

No. I didn’t draw a rectangle. There’s no need for that if you import as an image.

You can trace right on the image as if on a face. You may need to zoom in closer or look more straight down. It takes a little practice but it’s not difficult.


#16

Ok… Try it right away…


#17

Sorry to bother you again Dave…

Now that’s what I did… just as you said… but how do I turn it into a 3D object now… (I grouped it… but then ???)


#18

Before making the group, did you make sure the loop is closed and you have a face inside the loop? Now that it is a group, open the group to work on it. Once you have a face, you should be able to use Push/Pull to make it 3D.


#19

Trying to find out if it is closed… But can’t get the face… Guess then it is not closed…


#20

How about saving it and uploading it so I can see it?