Custom Fit Bottle Cover Pattern

A friend of mine has a tight-fitting, zipped, neoprene bottle cover in a Union Jack print that came free with a bottle of Champagne she bought for the late queen’s platinum jubilee. I fancied one for myself – neoprene is used for wetsuits, it's thick, tough and will keep a bottle chilled for a while, which makes it ideal as a protective bottle cover to take on picnics. I used this desire as a reason to learn how to use Meshmixer (which is free) in combination with a CAD package such as Fusion 360 (also free for personal use) to model any size and shape of rounded bottle and produce a bespoke paper pattern.

Follow the instructions in Steps 1-8 to make your own custom-fit cover, or just download the pattern attached to Step 6 to make a cover that should fit most 75cl sparkling wine bottles. The blue one I made in the photos is a trial run in medium weight jersey fabric because I haven't yet been able to get hold of some neoprene.

A bespoke bottle cover would make a great present for someone who has a favourite tipple, or just as an addition to a gift of a special bottle. But this method is only suitable for bottles that have rotational symmetry about a vertical axis – in other words, round bottles - because of the way the zip spirals around the bottle from base to neck.

You will need:

1. Access to Fusion 360 and Meshmixer
2. The bottle you want to make a cover for
3. A tape measure
4. A printer and paper

In addition, to make a cover from the pattern:

1. Two-way stretch fabric such as jersey containing Lycra/Spandex, or even neoprene
2. A zip about 34-36cm / 13-14” long, of a weight to suit the fabric
3. Sewing supplies – scissors, pins or clips, needles, thread
4. A sewing machine
5. Optional - an overlocker/serger

Wine and spirit bottles vary in shape and height quite considerably, so we need to start with some measurements. 

Using a tape measure, write down the bottle’s circumference at the base, around the neck and elsewhere if it isn’t cylindrical below the shoulder point where it starts to curve up to the neck. A sparkling wine bottle has extra bulk around the cork and its wire cage, so you will need to work from a full bottle rather than an empty one. Measure its neck diameter wherever it’s widest, it isn’t practical to make a bottle cover that varies in diameter in the neck zone. 

Also record the height of the shoulder above the base, the height of the point at which the neck becomes cylindrical and the total height of the bottle. Basically, you need to take and record enough measurements to be able to recreate the bottle digitally, because that’s what you’ll do next. But it doesn’t need to be too detailed or exact because the cover is going to be made from a stretchy fabric. Don’t bother, for example, measuring any minor features such as the lip around the mouth of the bottle if it has one.

The instructions in this step assume you are using Fusion 360 to model your bottle, but other CAD systems will be broadly similar.

There are two main ways of tackling this. The first method would be to draw a series of horizontal profiles of the bottle at different heights and then loft between them. For a simply shaped bottle such as a classic claret bottle – straight, cylindrical sides up to the shoulder and then a straight cylindrical neck – you don’t even need to do much lofting. The claret bottle in the image above was created by extruding upwards from a base circle, downwards from a circle for the mouth of the bottle, lofting from one extrusion to the other and then filleting the two joins to make smoother transitions.

But for a curvier bottle like one for sparkling wine another method is more appropriate: drawing the sideways-on profile of the whole bottle and then rotating it about the bottle’s vertical centre line. That’s the method I describe below.

Start by creating a sketch in the XZ plane and drawing a horizontal construction line from the origin of the same length as the radius of the base of your bottle. The formula you need for that is ( A / ( 2 * ( PI ) ) ) * 1 mm where A is the circumference of the base of the bottle in mm. Draw in a second horizontal construction line for the mouth radius at the appropriate height.

Then, using the measurements you took in Step 1, draw in the side profile of the bottle working from the end of the horizontal baseline up to the top of the bottle’s neck. Straight lines are easy, but if the bottle is curvaceous you’ll have to draw a series of points at the heights where you took measurements of the bottle’s circumference and then connect them with a spline curve.

When you think you’ve created a good outline of half a bottle when viewed from the side, test it by zooming to a 1:1 scale and holding the bottle against the computer screen – you may need to pan the view to compare the top and bottom parts of the bottle separately unless you have a large screen. Alternatively, take a screenshot of the outline, enlarge it to the correct size, print it and test your bottle against it that way. Make any adjustments that are needed to perfect the fit.

Now finish the sketch and switch to the Surface tab in Fusion 360. Revolve the side profile through 360° around the Z axis to create a model of the outer surface of the bottle, minus its base. (The base is a simple circle so we don’t need to do anything fancy to make a pattern for it.) Modify the surface body's appearance to green glass if you want it to look more bottle-like.

The fabric we’re going to make the bottle cover from starts off flat, and although a 2-way stretch jersey will deform to accommodate a curved surface – even a non-developable surface* – the cover will fit best if we can keep the deformation to a minimum. Making the cover from a base circle stitched to just one other piece of fabric with a vertical opening up the side of the bottle would result in a lot of distortion, possibly more than any stretch fabric could accommodate. The solution the manufacturer of my friend’s Union Jack cover came up with looks ideal – a base circle plus two identical pieces that spiral around the bottle. That’s what we’ll do.

So, we need to split the bottle surface we created in Step 2 into two identical pieces which connect to each other by seamlines that spiral 360° around the bottle on opposite sides, from bottom to top. To make the fabric cover, one seamline will indeed be seamed, the other will be zipped.  

The steps needed to do this in Fusion 360 are:

1. Still in the Surface tab, create a new sketch in the XZ plane and project the bottle body into it. Draw a line from the origin up to the top of the bottle.
2. Create a new surface body using a single path Sweep with the horizontal base line as the profile (untick the "chain selection" box), the vertical centre line as the path and a twist angle of 360°. Be sure that the orientation is set to perpendicular.
3. Split the bottle body using the new body you just created as the splitting tool. This cuts the bottle into two. Remove the splitting tool and the two remaining bodies should form a whole bottle body. Because they are identical, we only need to work with one of them to create a pattern for a bottle cover so you can remove the other one as well if you like, to avoid confusion. 

*A developable surface is one that can be unrolled to a planar surface - the curved surfaces of a cylinder and a cone are examples. A non-developable surface has curvature in two directions and can’t be flattened without distortion, like the surface of a sphere.

This spiral-cut surface body can’t just be flattened by switching to the Sheet Metal tab, unfortunately, because it's non-developable. Instead we need to move to Meshmixer in order to distort the surface to make it planar. Before the move we need a mesh body.

Change to the Mesh tab and convert one of the half-bottle surface bodies to a mesh using the Tesselate command in the Create menu. I used the default medium refinement settings.

The new mesh body that appears in the browser will have a warning that it isn’t closed and doesn’t have positive volume, but don’t worry about that. To export it, right-click it in the browser and select Save as Mesh, choosing the STL (ASCII) format. Download the STL file to your computer ready to import into Meshmixer.

Meshmixer is no longer being developed by Autodesk, but it can still be downloaded freely here. I find it useful for doing things like this that can’t be done in Fusion 360, or at least, not in the version that's free for non-commercial use. I suggest you get it while it’s still available, it might not be for ever.

Open Meshmixer and use File, Import to import the (half) bottle cover STL. From the Edit menu, select Unwrap. Just leave the settings at their default values with the unwrap type as Rigid.

On accepting the settings a flat body will appear, and also an object browser window. If you find your mesh body won’t flatten, choose Analysis, Inspector from the menu on the left, then Autorepair All. With luck, unwrapping will work on the repaired mesh.

In the object browser, turn off the visibility of the curved mesh body you imported to leave just the flat surface (called Unwrap 1), and select it by clicking on it. Then you can use one of the Export options in the File menu to export it. I wanted a format I could import into Inkscape or back into Fusion 360 in order to add seam allowances, etc to my pattern, so I chose Export SVG, but other export formats are available by selecting Export.

Now we need to add seam allowances to the vector outline downloaded in the last step. In Fusion 360 proceed as follows.

Create a new component to keep things neat and call it Pattern. Working in the Surface tab, choose Insert SVG from the Insert menu and select the file you made in Meshmixer. You'll need to select a plane for the new sketch that contains the profile of the flattened bottle side.

Add an Offset (from the Modify menu) all the way around the perimeter for the seams and the hem at the top. Start by selecting the entire outline using window selection, because the perimeter is made of lots of very short lines. I suggest a 8-12mm seam allowance, depending on how thick the fabric is. However, bear in mind:

1. You need to consider the width of the zip you’re going to use and choose a suitable seam allowance for the spiral edges that will be closed with the zip. If you're using a fabric such as neoprene that’s too thick to stitch onto the zip tape with the raw edges hidden as is usual, then a negative seam allowance is required – in other words, trim some way from those edges because the fabric will be sewn wrong side down onto the zip tape.
2. You'll be cutting out two pieces of fabric that are identical apart from the seam allowances, without flipping the pattern over before cutting the second piece or cutting the fabric double with right sides together as is usual. The concave curve of one piece of fabric joins to the convex curve of the other and vice versa. That means that the seam allowance for each curved edge will differ depending on whether that edge of that piece of fabric is stitched directly to the neighbouring piece or is attached to the zip tape.
3. You might possibly want to allow extra on the top edge for the hem around the bottle's mouth. But a single hem is usually fine for a jersey fabric so it doesn't really need to be any bigger than the seam allowance.

Either make 2 pattern pieces, one of which has a zip-suitable allowance on the concave side with a seam-suitable allowance on the convex side, and the other one the other way around, or just cut one with the maximum allowance you need on all edges and then trim away any excess from the fabric pieces later. That's the approach I've taken with the PDF pattern attached below, all edges have the same 10mm allowance.

Having finished the pattern you can save it as a DXF for digital cutting by right-clicking on it in the browser. Or to print it as a PDF, first Patch the profile between the two outlines (stitching line and cutting line) to create a surface body then Thicken it to make a solid body. That done, switch from the Design to the Drawing environment and make a drawing of the solid body at 1:1 scale. This can then be printed using Print from the File menu. Add at least one dimension to the drawing so that you can check the scaling is right by measuring the print.

For the base of the cover, just draw a circle of the same diameter as you used for the base of the bottle model earlier and add the same seam allowance as before. If you put it in the same Fusion 360 sketch as the pattern for the bottle side and patch and thicken it as before then you can include it in the same drawing. You might need to move the base around in the sketch to get both pattern pieces to fit on the same sheet of printer paper, in which case save the design before switching back to the drawing and clicking on the link icon (highlighted with a yellow warning) at top left to update it. I was able to fit both pattern pieces on an A3 sheet.

The best way to place your main pattern piece on the fabric is with the straight edge at the bottom aligned with the direction of greatest stretch, which is usually across the width of the fabric.  But as long as you are using fabric with good stretchiness in both directions it won’t matter too much. Try to cut both pieces in the same orientation though, or at least head to tail as in the layout above, so they will look the same on the bottle. And don’t forget that you need to cut two identical pieces with the pattern the same side up each time. If you place the pattern on the fabric (both times) so that it appears to lean to the right (as in the photo above) then the zip will close from left to right. Flip it over for a closure that works the other way around.

Cut out carefully, accuracy is important for a good fit. Place the two pieces on top of each other, both right side up, when you’ve cut them and check they’re the same.

Trim off any excess from the seam allowances of each piece in turn along the zipped opening edges, remembering that this means the convex side of one piece and the concave side of the other. Mark these edges so you remember where the zip is to be inserted.

Now cut the circle for the base.

The spiral seam, the seam around the base and the hemmed top opening should all be sewn using a stretchy stitch to prevent the thread from breaking if the cover is stretched when it’s put on or taken off bottle. An overlocker / serger is good for this, especially if you have the facility to sew a flatlock seam on thick fabric such as neoprene or a cover stitch hem. However, a fairly narrow zigzag on an ordinary sewing machine will be fine as long as the stitch length is short.

The zip can be inserted with a straight stitch because it won't stretch. Measure the length of zip required from the hem fold line at the top edge of your pattern along one of the spiral seamlines to the stitching line at the bottom. Use a tape measure on its edge or a piece of string. The length along the concave side may not be exactly the same as the convex side because of the distortion introduced by the flattening process in Meshmixer, but they should be close. Choose a zip that’s a little shorter, say 3-4cm / 1-1½", than the longer measurement, because the bottom of the bottle cover will be neater and less bulky if the zip starts just above the base.

Pin or clip the zip tape to the stitching line of one of the pieces of fabric, ideally the one with the longer opening edge. Start from just below (say 3mm / 1/8”) the hem fold line at the top and work down until you are about 3cm / 1¼” from the bottom edge. Mark the zip tape at this point then unpin it.

Now make a zip tab for the bottom of the zip from a piece of the leftover fabric. Cut two strips the same width as the zip (including the tape), each about 7.5cm / 3” long. Place them as shown in the photo, right sides facing with the zip between them, and stitch across the zip through all three layers at the lowest point of the marked line, taking a narrow seam. Trim away the excess zip leaving just 10mm / ½” or so beyond the seam you just sewed. Then fold both strips down to encase the cut end of the zip and topstitch through all layers close to the fold. Tack the edges together.

Pin or clip the zip with its tab in place to one fabric piece as before, from the top downwards, right sides together unless you’re using a heavy fabric such as neoprene in which case the neoprene’s wrong side should be laid on the right side of the zip tape. Then stitch that seam. At the bottom, trim away the excess zip tab level with the edge of the fabric piece - it will be at a slant, see photo above.

Stitch the other side of the zip to the other fabric piece in the same way, top down, stretching the fabric a little if necessary to make the bottom of the zip tab line up with the bottom edge of the bottle cover. Apart from this, take care not to stretch the fabric when inserting either side of the zip or it won't lie smoothly.

At this point you can close the zip and try the cover on the bottle, clipping or pinning the remaining spiral join. Adjust the fit if necessary by marking where the seam allowance needs to be a bit bigger or smaller, but the stretchy fabric should cope with any minor discrepancies.

Stitch the spiral seam either by overlocking it or by using an ordinary sewing machine. For a conventional seam, either trim the seam allowances afterwards and press them downwards towards the base of the bottle, or else press the seam open and topstitch on either side (again with a stitch that will stretch) to hold the seam allowances in place. Open the zip to give more room before doing this topstitching.

Sew the final seam that attaches the circular base. It helps to mark the quarter points of both the base and the spiral-seamed side of the cover first by folding, then those quarter points can be matched up to make sure the base is sewn on evenly. Pins are easier to use than clips for something so small and fiddly, and I recommend stitching with the base underneath so you can make sure the seams you've already sewn lie smoothly. Trim the seam if you didn't use an overlocker and press the allowances away from the base or they could cause a bottle to wobble.

The final step is turning under a single hem at the top. Open the zip, tuck under the ends of the zip tape neatly and topstitch the hem down using a stretchy stitch.

Voila! A custom-fit bottle cover that you can use to protect bottles you’re taking on a picnic or to a friend’s house, or as a gift wrapping for a special bottle.

For another Fusion 360 textile design, check out my Parametric Bucket Hat With Pattern 'Ible. Or for a simpler bottle cover see Blind Tasting Bottle Bags.