Deborah R. Fowler
Color Illusion
Posted Dec 27 2019
Updated Jan 11 2020
Updated June 22 2023 to include recent video
Continuing with Illusions, from https://neurosciencenews.com/visual-reality-14590/ The recreation of this illusion was reproduced in Houdini with both geometry and shader work.
The pattern was produced to create a texture map given below. This was created using a point wrangle node to create sin curves, skin over a pair and then modified a constant shader with a ramp parameter to produce the color stripes based on st. This pattern was then mapped back onto the geometry as well as two other pieces of geometry that were boolean'd out with a circle of division 4, slightly scaled and offset on the z-axis.
The illusion becomes more dynamic when the middle layer's texture is flipped (note the black and white strips in the pattern).
Jan 11 / 2020 - Checking my website on mobile phone the other day revealed that the perceived movement of this still image is mostly lost at the small resolution of a phone screen. Interesting. Best viewed on laptop/desktop.
There are some interesting articles related to how size of image affects our perception. How will this influence how immersive reality visuals are perceived? How does this translate into AR and VR?
- https://cxl.com/research-study/product-image-size-value/
- https://www.sciencedirect.com/topics/psychology/size-perception
- includes some informative articles regarding definitions and descriptions of illusions such as this one https://www.researchgate.net/publication/232569118_Illusions_at_century's_end
June 22 / 2023 - Adding a new version of this creating an animation showing the illusion emerging. All of the images above are without any animation, just still images.
Best viewed on desktop. There is a false sense of motion in this color illusion inspired by an article in https://neurosciencenews.com/visual-reality-14590/ showing work by Don Hoffman. As the lines become more wiggly, the illusion becomes more pronounced. Only the texture lines are animated, there is no rotation occurring.
After the first 12 seconds, it is only a still frame, no changes. Created in Houdini 19.5.303 and rendered in Mantra.
Also on youtube https://www.youtube.com/shorts/YJjaeuM-Mo4