<a-curvedimage>

Note: This documentation is for the old 1.4.0 version of A-Frame. Check out 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.