Design a bottle concept in 3D

Start from the cap

The neck of a bottle is usually designed around a closure, not the other way round. Most plastic bottles use standard neck finishes so they can take stock caps, pumps and sprayers. In North America these are named by diameter and thread style, such as 28-400 or 38-400: the first number is the diameter in millimetres, the second the thread style. Carbonated drinks in PET use their own family of necks. A custom neck means a custom closure and more tooling, so ask suppliers which standard caps and pumps they offer before you settle on an unusual neck.

In the concept the neck and cap are parts with sizes, so you can match a stock cap's diameter. The thread itself is not modelled.

How bottles are made

• Blow moulding: hot plastic is blown against the inside of a mould. PET drinks bottles are usually stretch blow moulded from a preform; HDPE bottles for shampoo and detergent are usually extrusion blow moulded. Walls are thin and vary around the shape, and sharp corners thin out most, which is why moulded bottles have generous radii.
• Injection moulding: plastic is injected between two halves of a steel tool. It suits caps and closures and some thick-walled, wide-mouth containers, where the wall thickness must be controlled. Shapes that narrow and then widen again are difficult to release from the tool.
• Stainless steel: insulated bottles are two steel walls with a vacuum between them, formed and welded. The insulation costs width and weight, so the outside is noticeably larger than the space inside, which matters when the bottle must fit a cage or a cup holder.
• Glass: blown or pressed in moulds, with thicker, heavier walls. For a small brand, a stock glass bottle with its own label is often the practical first step before a custom shape.

Check the volume yourself

A concept gives sizes, not capacity, so do the arithmetic before you show it to anyone. Internal volume is roughly the inside cross-section multiplied by the inside height. A cylinder 7 cm across on the inside holds about 38 ml per centimetre of height, so 750 ml needs about 19.5 cm of internal height before you add the base, the shoulder, the neck and some headspace.

Bottles are sold by the volume they are filled to, and the brimful capacity is always larger. A double wall or a thick base takes space from the inside, not the outside. A supplier will confirm the real figures.

Designing a bottle in Kubikly

• Choose Describe it, or Upload a sketch if you have drawn the silhouette, and set the kind of product to Bottle.
• Give the outside limits you know: a maximum diameter for a cage or a cup holder, the height of the shelf it has to stand on.
• Name the closure: screw cap, flip lid, pump, straw lid. It becomes its own part.
• Shape the silhouette by talking: “narrower waist”, “rounder shoulder”, “make it 24 cm tall”.
• Make colourway variants and render them in Studio, then an In use shot where the bottle lives: a bike, a gym bag, a bathroom shelf.
• Print the presentation page and take its open questions to a bottle supplier: neck finish, material, process, minimum order.