There are way too many maps on osu! that have 2B and don't use it right, so I experimented with how the 2B system works and how to utilize it effectively.
I found out how to use 2B in a beatmap without fear of autofail and without having to constantly use trial and error.
Thanks for reading! I hope this helps anyone trying to map 2B
I found out how to use 2B in a beatmap without fear of autofail and without having to constantly use trial and error.
First to note is the constant for how long you have to worry about 2B.
To find this, highlight over the metadata for your beatmap. The "Approach Time" is the most important part of using 2B. In this map, my Approach Time is 600ms (milliseconds). Remember your Approach Time, as it's key to figuring out how long you have to reset your 2B.
Second to note is that 2B works best when the first object in the 2B sequence is a slider. This is because when deciding how long the first slider can be, osu! uses the first object in the sequence.
If you do as shown below, it'll treat the slider head of the highlighted object as the basis for how long the slider can be.
However, if you do as shown below instead, it'll treat the slider end of the highlighted object as the basis for how long the slider can be.
Notice that all I did was switch around the order of the objects. The arrangement is still exactly the same.
Third to note is that with each layer of 2B in the 2B sequence, the amount of circles you can put before you need a new slider increases.
This is a bit more complicated, so this explanation will use a few reference images.
Imagine the blue here is a slider and the red is a beat. With a regular 2B slider, you can have 1 beat before you have to worry about the timer.
Luckily you can stack the amount of beats by using a slider. Just make sure that the slider is the first thing in the sequence and that the slider end of the additional slider is close to your original slider by the amount listed in your Approach Time.
So a working double slider would look like this:
With each new slider, you can add an additional number of beats as long as a slider comes before it.
You can continue this for as long as you like and as long as the rhythm in the map supports it. Just remember that the slider end of the new slider is close to the slider end of the old slider by the amount of your Approach Time.
Last to note is that using a repeat on a slider will allow you to extend how long you have to worry about Approach Time.With all of this in mind, you can make what would otherwise seem unpassable playable by considering the effect autofail has. Like the picture below:
If you have a base slider that's huge like this picture and very long, but you want to use a smaller slider for either aesthetic or practical playing purposes,
you can actually use a repeat to make a smaller slider work in 2B.
Ordinarily, something like this wouldn't work since the slider end of the 2B slider is far away from the slider end of the base slider.
But by adding repeats to the 2B slider, you can extend the theoretical tail of the slider and cause it to still work well with short sliders!
This one doesn't autofail and should get you passing, though be sure to keep in mind practical issues with testplaying and making sure the placement feels right before proceeding.
Thanks for reading! I hope this helps anyone trying to map 2B