# The correct way to make this surface

Hello,

I am working on a shampoo kind of bottle. Horizontal base and top ellipse like, horizontal middle sharp corners.
I’ve drawn the main profile curves.

1st attempt. when I use curve network it results in round corners where my original curves have sharp corners.

2nd attempt. So next I’ve split the horizontal profile curves, and used 2 rail sweep on the sides. Then connecting the side pieces. First I’ve tried using curve network again using the surface edges of the 2 rail sweep results, but of course again I lost the sharp edges (tangency). So next I’ve used curve network again but now using the original profile curves. This looks ok but don’t I loose continuity at the base and top? Since the curve network doesn’t get information from a surface but just a curve?

Was wondering if I am doing this in the correct way?
Also for the capping, what approach would be usually used to make a round cap like this?

Thanks!

forum_surface.3dm (531.1 KB)

The Level 1 Training Guide has a tutorial for a similar bottle.
You might want to look at that for techniques.

Hi Jon, There’s indeed a bottle, but it doesn’t really answer my questions, right? I was just curious how the pro’s would handle this starting from the given profile curves? But thanks for pointing out to this great guide!

You haven’t really asked any real questions.
The “correct” way is you getting the shape you want.

A kink or sharp edge is position continuity or G0 as in your third image. Tangency is G1 and curvature continuous continuity is called G2.
I can’t tell what continuity you selected for your rails in the middle image.

The tutorial makes a similar squeeze bottle with a variety of techniques and end up filleting the face of the bottle to the shoulders. Fillets produce tangent edges so they are G1.

In the middle image I used G1, so it make sense the curve network rounds that connection, but how can I keep continuity at top and bottom but still have a sharp corner in the middle? Attached the highlighted curves that I need to follow.

Something more like this?

Yes! Curious how you did that?

Split/Join the vertical curves.
I also rebuilt the horizontal curves to smooth out the shoulder tangencies from the Arcs. This was causing a slight depressing in the face of the surface at the midline.

forum_surface_Tweaked.3dm (664.3 KB)

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Thanks John, Just not sure what you mean with Split/Join the vertical curves? Did you use curve network?

I selected the curves split and joined so you would see them in the screenshot.
Network curves need to go in two directions in a grid-like manner.