# Nurbs and Time travel

I know it sounds crazy.
A time line is something like a Nurbs curve, a curve with no kinks. Can we control a time line by moving its “control points”?

Let’s assume a time line like a open Nurbs clamped at start and end. We move the control points in the middle what ever we want, but leave the knot information unchanged. In other words, if a Nurbs curve topology keeps unchanged, we can consider this Nurbs curve is the same one. What I want say is that if we morph a time line like this method, is it possible make a “legal” time travel?

“Continuity” – a key concept shared by both time and Nurbs. By this means time line doesn’t suddenly change its direction like a polyline.

If I move a control point which has decade interval with its neighbors, humans living by days will not notice time line has been altered. Because the change is very gentle by people perception and it back to original end point, this is so called “legal” time travel.

Time doesn’t exist.
Objects exist. Objects move. We can compare one object’s movement with another object’s movement. Time is just “agreement” on which base sample object’s movement to use as reference.

So, what is a timeline?
Fiction.

You would have a “legal” time travel even with a discontinue timeline (aka time teleport), or with a sharp and sudden change of the direction (like turnstiles in tenet)… or even an “illegal” time travel with a plain straight timeline… it all depends on the suspension of disbelief reached in the fiction context.

On Bioshock Infinite this timeline:

feels smooth as a degree 11 nurbs…

Honestly, I feel time is fiction, too. Nurbs actually is not “curve”. I cannot draw or see a Nurbs. A curve is display agent of Nurbs for better perception. I use “time line” to represent time for the same reason. I want readers can quickly pick up what I want mean.

Nurbs is a math concept, I cannot claim it is physical. I think time line is also. A nurbs is a close math description to time line, becsuse as you said “feel smooth”.

A timeline is usually drawn in a bidimensional space, and usually time is on the abscissa , the X axis.
… and on the ordinate/Y? What is that?
The smoothness of the timeline means really little.
We care only about the start and end point of the segments, not their shape. Even worse, we care only about the X coordinate of the start/end points of each segment!

Y axis is only used to avoid entangling timelines and to let us see better the drawing.

I’ve taken the liberty of changing the category to Meta - I wouldn’t want McNeel adding time editing tools to Rhino until Subd is finished.

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I feel that maybe even blocks are up for a revamp before we start messing with the whole time/space-thing, but maybe that’s just me…
-Jakob

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Well, if we master time travel, then maybe we can just fetch all these as completed features from the future no?

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Dunno, that would create a self-intersecting curve in the timeline. If that’s bad for Nurbs…

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Time does exist, it is not an illusion. What is an illusion is how a human subjectively interprets the time because our time measurement system is arbitrary, from how time works in the mind to conventions such as seconds or hours. Without time (and/or without space) there can be no movement, because a dimension is needed to separate one state from the other, otherwise you would have to accept that an object is in all the positions in which it was, is and will be, at the same present, which is nonsense because it compresses the past and the future to the present and the reality we see is not like that, an object is here now and there later, not both at the same present. Time is that which allows you to differentiate that change, is not something material because it is more fundamental than matter/energy itself, just like space. And although time is relative to the frame of reference, this only changes its speed (t1-t0), not its existence. If time did not exist, we would live in an absolutely frozen and unperturbed universe.

The comments are interesting. By reading them I can explain clearly now.

One thing always bother me is that how to insert a moment or event to a time line (of cause the moment is not on the original time line). It can be convert to a question how to insert a not-on-curve point to a curve. If the curve is a polyline, the insertion breaks the curve. In other words, the original line stops at insert point and then move to the next. However this not I want, because time cannot be break at some moment.

Nurbs is such a genius idea that I realize I can insert a “control moment”, like control point of Nurbs. A control moment is not on time line so it will not break the line, but it does influence the time line in some way I want. This method avoids directly alter time line, so people will not notice the change.

Yes, of cause. Time travel is not only to travel to the pass. It is to future as well. A Nurbs needs next control point unit it reach at end. Beginning and ending are pre-set before drawing wherever in pass or future. To traveling to future, we set an end point in future, and then draw a Nurbs curve from present.

Length does not exist. Objects exist. Objects have sizes. We can compare one object’s size with another object’s size.
I think the same about time.
@Dani_Abalde , your comment says the exact opposite of my opinion , like time exist and thanks to its existance things move.
I think things move, as an intrinsic propriety like “being yellow” or “being 50cm wide”, and because of that we compare one speed with others: time.
There is a background “tensor”, but that itself is an object moving, physically colliding with “real” objects, etc etc…

@zhuangjia777 your idea of timeline is currently more vague than time itself, for me.
Can’t you post a picture?
Is it 2D? 3D?4D?

You see. Coordinates are different to observers. From a view of a traveling point on the curve, there only one dimension which is along the tangent.

Indeed, human’s traditional perception of time plays a big rule on our daily life. Many people believe the logic that formed by time. For example, that reason causes result imply a sequence that reason happened before result.
But if I tried think reverse the sequence: could result decides reason? It is totally ok. Just make people feel unnatural if I speak in reversed way.

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I could use that same hypermaterialist interpretation of existence and tell you that objects do not exist and that only fundamental particles exist. It is arbitrary that you give existence to objects, which are a concept that identifies an organised group of atoms, and not to length, which is another concept that identifies a property of an organised group of atoms. That one identifies a differentiable type and the other identifies a differentiable property of a type, but both exist because both are differentiable entities and independent of the observer. At least for me that’s what existence is, they are objective manifestations whose value is equivalent regardless of how you interpret them, this can only happen because something really exists. Length is a physical property and time is a physical dimension.

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obviously you avoided the medieval times, you might have not returned otherwise with such sorcery

Time will feel like not passing by at all, if stuck in a German traffic jam (likely each 200 km). It’s like locally increasing the weight of your NURBS path by some magnitudes. So no, you cannot travel back in time, but you can notice the time dilation by the almost-infinite amount of cars (and their masses).

Or maybe it’s again just a “pseudo hacker” delivering spam links for scams. I wonder if this actually pay off?

I think he just traveled back in time far enough to the point where he doesn’t exist anymore…

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