This page concerns the Vuforia Engine API version 9.8 and earlier. It has been deprecated and will no longer be actively updated.
Cylinder Target images are subject to the exact same qualities, methods and requirements as Image Targets. However, there are some preliminary steps and considerations that you must consider, such as the bulging and stretching of the image that wraps around the cylindrical or conical shape. This article will equip you with the right tools to prepare and design Cylinder Targets.
Attributes of Cylinder Targets
As mentioned before, Cylinder Targets are images undergoing the same evaluation and rating as Image Targets. Therefore, we recommend you to visit the Best Practices for Designing and Developing Image-Based Targets article to understand the setup and qualities a good target image possess.
Typical real-world objects are usually not perfect cylinders. Instead many cylinders are conical shapes with a pointy end. Cylinder Targets consist of a top, bottom, and length target image; the latter also being referred to as a label.
The Parameters of Cylinder Targets
The parameters of a Cylinder Target must be defined in the Target Manager when creating a new Cylinder Target. The following table provides guidelines for defining these values.
Parameters |
Description |
|---|---|
| Dimensions |
Define the cylinder dimensions in meters. TIP: However, the top, bottom, and side length can be changed at runtime by manipulating the overall scale of the Cylinder Target. This provides a flexible way to define or update the size of the Cylinder Target in your 3D scene. Just remember that changing the scale of one part, will also affect the two others accordingly to preserve its proportions. NOTE: Your Side Length can be defined longer if necessary, but the Top Diameter and Bottom Diameter must be the correct dimensions. NOTE: Developers looking to use Cylinder Targets in combination with Positional Device Tracker should specify the target size in meters. |
| Unique Target ID |
A system-wide unique identifier (string) to identify Cylinder Targets across any other datasets. Maximum string length: 64 characters Character set can consist of a-z, A-Z, 0-9, _- |
Cylindrical Shapes
Example of a label design wrapped around a cylindrical can.
Cylinder Targets deals with wrapping a piece of 2D graphic on a round object in various diameters and shapes. To help you figure out the wrapping process, we present in this guide a series of examples of extracting the relevant cylinder shapes and adding the correct dimensions in the Vuforia Target Manager.
Standard Cylinder Can
In most cases, the images of can labels tend to cover the whole can, for a full 360 wrap. Depending on the label design, you may have to account for seam lining and cutting marks, but the overall shape is a simple rectangular. The input of the Side Length is the height of the rectangular.
Bottles with a Front Label
In alternate cases, the label does not completely cover the product as in the cases for wine bottles. Here, you would design the label as a small band to fit the top and bottom dimensions and the length. The design of the Cylinder Target still requires you to add a Side Length dimension that can wrap completely around the bottle. You leave that excess area in white and cut it away before placing the band on your product. The Input for the Side Length would also be the cylinder height.
Conical Shaped Product
Some products and objects are not uniform in the top or bottom. For example, the bottom of a cup is usually having a smaller diameter than the top of the cup, resulting in a somewhat conical shape. Therefore, a conical shape cannot simply be cut as a rectangular image and wrapped around, instead, you will be required to calculate the shape of it. Follow our guide on How to Calculate Cylindrical and Conical Cylinder Targets for an in depth guide to calculate such dimensions.
Similar to that of labels, which only covers a part of the product, conical labels can be printed with white space to avoid warping and stretching.
Cylinder Target Orientation
The origin of the local reference frame is located at the center of the bottom side of the cylinder, with the Z-axis oriented vertically. The following picture is an example of a Cylinder Target with 3D augmentations. The coordinate axes are highlighted to illustrate the cylinder reference system.
