# Unexpected behavior: Sin(time) seems to be "invisibly" remapped

**URL:** <https://forums.unrealengine.com/t/unexpected-behavior-sin-time-seems-to-be-invisibly-remapped/404338>\
**Category:** Rendering\
**Tags:** parameter, unreal-engine, question\
**Created:** [September 11, 2017, 10:40pm UTC](https://forums.unrealengine.com/t/unexpected-behavior-sin-time-seems-to-be-invisibly-remapped/404338 "2017-09-11T22:40:18Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![BrendanLoBuglio](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@BrendanLoBuglio](https://forums.unrealengine.com/u/BrendanLoBuglio)\
**Post date:** [September 11, 2017, 10:40pm UTC](https://forums.unrealengine.com/t/unexpected-behavior-sin-time-seems-to-be-invisibly-remapped/404338/1 "2017-09-11T22:40:18Z")

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Hi, there! This is a quick, and maybe pedantic question about the Sin and Time nodes in Unreal, but I’m experiencing some odd behavior that I’d like to better understand.

**[In this screen recording](https://screencast-o-matic.com/watch/cbQX3ZIIod)**, I have a simple material set up with sin(time) going into the opacity channel (after being remapped from `-1,1 to 0,1`) – and the odd thing is, that produces an oscillation with a period of one second.

**In my mind, the expected behavior would be a period of 2π, or 6.28 seconds** , because the sin node receives an input in radians and the default period of a sin operation is 2π. Meanwhile, when I try to multiply the Time node output by `2π / PERIOD PARAMETER` in the video (which is what I would think to do in order to create a cleanly parameterizable period), I get an oscillation with 2π oscillations per minute.

So, what’s going on here? Does the sin node somehow “know” that it’s receiving a time input and trigger some special remapping behavior? Is my time input just operating on a 2π-multiplied scale? This isn’t necessarily a blocker, but if there’s some predetermined behavior I’d like to know how it works and be able to work around it

Much thanks!  
Brendan

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**Author:** ![Deathrey](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Deathrey](https://forums.unrealengine.com/u/Deathrey)\
**Post date:** [September 11, 2017, 10:59pm UTC](https://forums.unrealengine.com/t/unexpected-behavior-sin-time-seems-to-be-invisibly-remapped/404338/2 "2017-09-11T22:59:10Z")

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This is definitely an intended behavior.

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**Author:** ![BrendanLoBuglio](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@BrendanLoBuglio](https://forums.unrealengine.com/u/BrendanLoBuglio)\
**Post date:** [September 15, 2017, 10:58pm UTC](https://forums.unrealengine.com/t/unexpected-behavior-sin-time-seems-to-be-invisibly-remapped/404338/3 "2017-09-15T22:58:35Z")

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Hi, Deathrey! I agree that it totally seems intended, but my question is more with regard to the way that this is implemented – whether this happens only if the Time is directly hooked up to a Sin node or if Time → arbitrary node → Sin also works, whether there are other nodes that have custom behavior with Time input or sin output, and other things of that nature.

It’s obviously a nice convenience, but invisible behaviors like these can be dangerous if you don’t 100% understand them. Ultimately, I wish there was some documentation!