Creating faces

Does anyone understand what is going on here?

My aim was to create a sunflower seed pattern. I started with a pair of arcs drawn onto a plane. I then copied them radially a number of times. Then I copied the series of arcs I had created, mirrored them using scaling at -1, rotated them appropriately, and then moved them over the first set of arcs keeping the same centre. The creation of faces between the arc lines is very haphazard. Sometimes you get a face which cannot be painted (the one marked with an X in the screenshot, for example).

I don’t think this is to do with very small things (which I know SU isn’t good at). But as far as I can see, all the lines should be on plane and so should create faces between the lines that define the arcs.

Is there a better way of doing it?

Sunflower.skp (1.0 MB)

I’ve observed a few times that copying a flat shape which includes a face yields better results than just copying edges. Including a face in the source of what gets copied may help the SketchUp algorithms recognize that the edges are coplanar with the destination’s edges. SketchUp does a good job of eliminating when ends up as duplicate coplanar faces. I don’t know if this would help your scenario here, but you might draw the initial arc(s) onto some working face and then copy that face plus its edges onto itself (or onto another working face).

What’s the endgame? What is the final result that you are after?

I’ve found the most easy way to fix the most of this is with the “make face” plugin. just drag over it all and run it. Or select all and “intersect with model”

BUT, there are just some faces that don’t like to get made. Attached is a little exercise worth doing to show how some faces will not form despite all being co-planar. Worth drawing yourself to try it. Re-tracing over the edges doesn’t fix the face, nor drawing another rectangle over it, it needs a line drawn from it to the outer edge of the other box and then to delete that line. There is an explanation, but it seems to defy logic.

The reason I asked what you want as a result is you may have better luck with a single component rather than a mess of geometry.


What I am trying to create is a pattern that can be laser cut into steel. That means selecting individual faces that represent the “seeds” in a sunflower, but obviously not all of them or there would be no matrix of steel left. So I might have selected, say, every other “seed” in a whorl and then radially copied them to create the pattern. But I was finding the task of selecting the seeds tedious because faces were not forming and even drawing over lines did not necessarily create a face (as @TDahl has pointed out). I may have to try @whiterabbitdesigncompany’s solution.

here’s that extension, maybe it will help?

I’m not sure I understand this, if you select and all the seeds you have a very nice matrix left.
I think I get it now, I automatically saw the seeds as the holes in the overlap.

@Box that’s exactly the kind of thing I was aiming for. Did you construct it along lines in your earlier post?

Yes, but I did a 2d version that would be more suitable for what you need.
I just used a single 2d component, rotated and flipped in the same way as above, then arrayed and exploded. A quick intersect all faces, may or may not be needed, softened to make the inner edges Soft, then used selection toys to select just the soft edges and delete them, leaving you with one single face.

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