<a-curvedimage>

NOTE: This version of the documentation tracks unstable development happening on A-Frame’s master branch. If you wish to try it out, grab the unstable build. Otherwise, head to the documentation for the current 1.6.0 version

The curved image primitive creates images that bend around the user. Curved images arranged around the camera can be pleasing for legibility since each pixel sits at the same distance from the user. They can be a better choice than angled flat planes for complex layouts because they ensure a smooth surface rather than a series of awkward seams between planes.

Under the hood, a curved image is a double-sided open-ended cylinder with textures mapped to the inside of the cylinder.

Example

<a-scene>
<a-assets>
<img id="my-image" src="image.png">
</a-assets>

<!-- Using the asset management system. -->
<a-curvedimage src="#my-image" height="3.0" radius="5.7" theta-length="72"
rotation="0 100 0" scale="0.8 0.8 0.8"></a-curvedimage>

<!-- Defining the URL inline. Not recommended but more comfortable for web developers. -->
<a-curvedimage src="another-image.png"></a-curvedimage>
</a-scene>

Attributes

Attribute Component Mapping Default Value
color material.color #FFF
height geometry.height 1
metalness material.metalness 0
opacity material.opacity 1
open-ended geometry.openEnded true
radius geometry.radius 2
repeat material.repeat None
roughness material.roughness 0.5
segments-height geometry.segmentsHeight 18
segments-radial geometry.segmentsRadial 48
shader material.shader flat
side material.side double
src material.src None
theta-length geometry.thetaLength 270
theta-start geometry.thetaStart 0
transparent material.transparent true

Fine-Tuning

Ensuring that the image is not distorted by stretching requires us to carefully set the height, radius, and theta-length attributes relative to the image aspect ratio.

According to this formula:

S = r * θ

We need to calculate r or θ for S to match the height value preserving the original aspect ratio of the image. In this formula, θ is set in radians and radius and S properties are set in meters.

Arc formula

In degrees, thetaStart defines where to start the arc and thetaLength defines where the arc ends.

Once those values are fine-tuned to avoid distortion, we can use scale to safely adjust the distance of the curved image relative to the user.