# What is 3d?

We perceive at least four (4) dimensions:

- location in X
- location in Y
- location in Z
- location in Time

(x,y,z,t).

This brings up the question, then, of “what is 3D?”.

Does 3D describe`(x,y,z)`

, or, does 3D describe `(x,y,t)`

?

*Blender* says that 3D means `(x,y,z)`

.

*Flash* says that 3D means `(x,y,t)`

. Note that *Flash* is now replaced by the newer *Wick* project. I guess that *.gif*s falls into this category, too.

In fact, 3D is just a subset of 4D.

How many subsets of 4D are there?

4! = 24, but, order doesn’t matter. `(x,y,z,t)`

is the same as `(x,y,t,z)`

for our purposes.

The only thing that matters is which units are used to represent quantities in these dimensions. There are only 2 different units:

- spatial
- temporal.

Hence, there are only 2! permutations that matter to us.

I suggest that we name each of these permutations differently, when discussing them, e.g.

`3Ds`

concerns 3D using only*spatial*coordinates, e.g.`(x,y,z)`

`3Dt`

concerns 3D using, both,*spatial*and*temporal*coordinates, e.g.`(x,y,t)`

# Appendix - See Also

### References

https://guitarvydas.github.io/2021/12/15/References.html

### Blogs

obsidian blogs (see blogs that begin with a date 202x-xx-xx-)

### Videos

videos - programming simplicity playlist

### Books

leanpub’ed (disclaimer: leanpub encourages publishing books before they are finalized - these books are WIPs)

Programming Simplicity Takeaways, and, Programming Simplicity Broad Brush

### Discord

Programming Simplicity all welcome, I invite more discussion of these topics, esp. regarding Drawware and 0D

@paul_tarvydas

### Mastodon

(tbd, advice needed re. most appropriate server(s))