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Posted on 10/03/19 6:39:13 PM |
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DavidMac
Director of Photoshop Posts: 5554 Reply  |
How last weeks staircase illusion works:
Just in case it interests you here is a little bit about how the staircase illusion works rather better explained than at the time. 
The construction is a true 3D model which is rotated to a very particular unique view whereby the short gallery balustrade and the foot of the stair appear to be on the same level - which, in reality, is absolutely not the true case. This animation of the basic construction will show you how this works. The reason this trickery can be done is parallel projection. The parallels in this image do not converge to vanishing points. This means that objects at different distances remain the same size. Objects further away do not appear smaller. The short balustrade and the foot of the stair are in fact at completely different distances but I have suppressed this by making them appear the same size. If I now switch the camera in my 3D modeller to perspective the illusion collapses immediately because we can now clearly see the relative size and distances of the same short balustrade and the foot of the stair. Here is the true situation. My house of the previous week also depended on the same parallel projection otherwise the top and bottom halves would have had contradicting vanishing points. 
Parallel projection and non convergence often lie at heart of many illusions. One of the most famous illusions of all time M C Escher's "Waterfall" is constructed using exactly the same technique of parallel projection. So now you know .............  _________________ The subtlety and conviction of any Photoshop effect is invariably inversely proportional to the number of knobs on it ....... |
Posted on 10/03/19 11:09:19 PM |
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Steve Caplin
Administrator Posts: 6994 Reply  |
Re: How last weeks staircase illusion works:
A very useful explanation. Thanks, David! |
Posted on 12/03/19 06:39:06 AM |
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tooquilos
Wizard of Oz Posts: 2885 Reply  |
Re: How last weeks staircase illusion works:
David, thank you for this explanation, particularly watching the videos. Im still amazed how you do it! _________________ Wicked Witch of the West: I'm melting! I'm melting! |
Posted on 12/03/19 12:36:08 PM |
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lwc
Hole in One Posts: 3125 Reply  |
Re: How last weeks staircase illusion works:
Fascinating David, thanks for the explanation, makes me want to give it a go... although I know better than to even try. |
Posted on 12/03/19 5:09:50 PM |
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DavidMac
Director of Photoshop Posts: 5554 Reply |
Re: How last weeks staircase illusion works:
Since you are relatively new here Loyd you may not have seen my website. It's a bit old now and a couple of links are broken but if you are interested (or just feeling bored on a rainy day with no golf) there are plenty more illusions and a little bit of my professional movie work. _________________ The subtlety and conviction of any Photoshop effect is invariably inversely proportional to the number of knobs on it ....... |
Posted on 13/03/19 09:35:08 AM |
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Steve Caplin
Administrator Posts: 6994 Reply |
Re: How last weeks staircase illusion works:
Fantastic to see all those images again, David. Glorious work. |
Posted on 13/03/19 10:47:44 AM |
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DavidMac
Director of Photoshop Posts: 5554 Reply |
Re: How last weeks staircase illusion works:
Why thank you Steve! Praise indeed. _________________ The subtlety and conviction of any Photoshop effect is invariably inversely proportional to the number of knobs on it ....... |
Posted on 13/03/19 3:51:37 PM |
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Frank
Eager Beaver Posts: 1733 Reply  |
Re: How last weeks staircase illusion works:
Amazing work David, and like Loyd I'll leave it to you. Here's a cartoon which appeared in our local paper today which made me think of your work (cartoon by Bruce MacKinnon)  |
Posted on 13/03/19 5:25:09 PM |
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DavidMac
Director of Photoshop Posts: 5554 Reply |
Re: How last weeks staircase illusion works:
Strangely I posted something very similar right here in the gallery section not so long ago. Same principle and same origin .... M C Escher.  _________________ The subtlety and conviction of any Photoshop effect is invariably inversely proportional to the number of knobs on it ....... |
Posted on 13/03/19 5:25:09 PM |
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DavidMac
Director of Photoshop Posts: 5554 Reply |
Re: How last weeks staircase illusion works:
Strangely I posted something very similar right here in the gallery section not so long ago. Same principle and same origin .... M C Escher. _________________ The subtlety and conviction of any Photoshop effect is invariably inversely proportional to the number of knobs on it ....... |
Posted on 13/03/19 5:26:51 PM |
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DavidMac
Director of Photoshop Posts: 5554 Reply |
Re: How last weeks staircase illusion works:
Oops. Double post removed. _________________ The subtlety and conviction of any Photoshop effect is invariably inversely proportional to the number of knobs on it ....... |
Posted on 13/03/19 5:28:16 PM |
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DavidMac
Director of Photoshop Posts: 5554 Reply |
Re: How last weeks staircase illusion works:
Oops another double post removed. I think I am getting 'mouse bounce'. Double clicking when pressed once. _________________ The subtlety and conviction of any Photoshop effect is invariably inversely proportional to the number of knobs on it ....... |
Posted on 13/03/19 7:03:29 PM |
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lwc
Hole in One Posts: 3125 Reply |
Re: How last weeks staircase illusion works:
It would be nearly impossible for me to single out any one thing to comment on David. All of the illusions are great and quite enjoyable to behold. I did like the lighting for the Future Group commercial very much... all are wonderful indeed. Thanks for sharing the link. |
Posted on 14/03/19 11:59:55 AM |
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DavidMac
Director of Photoshop Posts: 5554 Reply |
Re: How last weeks staircase illusion works:
Glad you liked them Loyd. The movie work is relatively recent (although now I have retired that is no longer being updated) but the illusions have accumulated over twenty years. My very first was done in 1998, soon after I first discovered the possibilities of Photoshop. There's more unpublished or simply unsuitable for viewing at small sizes on a screen. Gives me a lot of pleasure ....... _________________ The subtlety and conviction of any Photoshop effect is invariably inversely proportional to the number of knobs on it ....... |