# Infinitely long 3D model

Let's say that I want to render something like Dimmadome's hat, a hat which has the height of infinity.

A quick answer to this would be to place the top side of the hat high enough for the crown(cylinder) to be cropped(like y=9999999...) half way in the view. I don't like this idea. So what I came up with is using IEEE 754 infinity in vertices.

(-0.5, INF, -0.5)
(0.5, INF, -0.5)
(0.5, INF, 0.5)
(-0.5, INF, 0.5)


(assuming the crown is a cube)

The problem is that after multiplying with the transform matrix, the vertices end up being all (INF, INF, INF), making them unrenderable. I just wrote this to give you an idea.

Is there any technique that can be used to achieve this? rather than using huge number? I wonder how they implemented this.

• Perhaps you could try using homogeneous coordinates with w=0. It's sometimes used to create shadow volumes that extend off to "infinity". Commented Sep 3, 2018 at 13:23
• In episode "Mission Responsible they mention: "... 80-story hat storage building" - while on other pages they mention regular size and "infinitely tall".
– Rob
Commented Sep 4, 2018 at 21:53
• What if you make the hat normal size but then use vertex shaders to always extend it so that it is barely larger than the screen? Commented Sep 15, 2018 at 9:54