問題描述
Blender: Kubus Mustahil (Blender: Impossible Cube)
I'm working on a graphics project trying to create an impossible cube in 3D. An impossible cube looks like that:
The trick behind this is two of the edges which are 'cut' and a picture taken from a specific angle to give the illusion of the impossibility.
Well I'm trying to make this but instead of a static image, I want to be able to animate it (rotate around) maintaining the impossible properties.
I have managed to make a cube in blender as you can see in the screenshot below:
I would like to hear your suggestions as to how I can achieve the desired effect. An idea would be to make transparent the portion of the edge that has an edge(or more) behind it, so that every time the camera angle changes, the transparent patch moves along.
It doesn't have to be done in Blender exclusively so any solutions in OpenGL etc are welcome.
To give you an idea of what the end result should be, this is a link to such an illustration:
3D Impossible Cube Illusion Animation
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參考解法
方法 1:
It's impossible (heh). Try to imagine rotating the cube so that the impossibly‑in‑front bit moves to the left. As soon as it would "cross" the current leftmost edge, the two properties of "it's in front" and "it's in the back" will not be possible to fulfill simultaneously.
方法 2:
If you have edge culling enabled, but clipping (depth‑testing) disabled, and draw primitives in the right order, you should get the Escher cube without any need for cuts. This should be relatively easy to animate.
(by Alex Encore、FeepingCreature、Ben Voigt)