Fusing a mod using multiple mods (such as duplicates), what??

[NekoHaxor]

I'm fairly new to warframe and I've been trying to figure out how I should upgrade my mods by fusing. There is the regular pressing the plus button and then paying the fees, but people are talking about using duplicates for fusing and I have no idea how that works. There is the "select mods from the collection to contribute towards ranking up x", but how do I select mods to do that? Every mod in my collection is greyed out, even duplicates. I find this really confusing, it isn't explained in the tutorial either.

[Katinka]

Before you start fusing into a specific mod, select multiple mods and you'll see the options on the top right offer to either sell the mods for Credits or convert into Endo.  You can select as many mods as you want (middle mouse to select entire stacks of duplicates) and then click the option to convert into Endo to be able to then use that Endo to fuse into a single mod.

The terminology used and some of the in-game advice tool-tips are fairly misleading as it used to be that you selected one mod, clicked 'Fusion' and then selected every other mod that you wanted to fuse into it until you reached the level required.  Hence you could select your duplicates (which used to give more if they were exactly the same mod) while fusing.  Even the term 'fusion' made more sense as you were directly combining a set of mods with another to improve it.  Now you break down your duplicates into Endo and fuse the Endo into the mods.  It has made it a lot quicker to level mods when you want as you just click the arrow to bump it.  Then if you run low on Endo, or just feel like tidying your collection, you can 'Sort by: Duplicates' and melt down all the stacks of spares at once.

[derp215]

That's the old fusion system. Now all you need to do is take the duplicate mods, the ones that you don't need, then convert them into Endo. Once you have enough Endo, you can rank up your mods.

[GinKenshin]

duplicate fusing is an old thing now. you can only rank up your mods by using endo now. however, duplicates that you don't need can be converted into endo

[NekoHaxor]

4 minutes ago, Katinka said:

Before you start fusing into a specific mod, select multiple mods and you'll see the options on the top right offer to either sell the mods for Credits or convert into Endo.  You can select as many mods as you want (middle mouse to select entire stacks of duplicates) and then click the option to convert into Endo to be able to then use that Endo to fuse into a single mod.

The terminology used and some of the in-game advice tool-tips are fairly misleading as it used to be that you selected one mod, clicked 'Fusion' and then selected every other mod that you wanted to fuse into it until you reached the level required.  Hence you could select your duplicates (which used to give more if they were exactly the same mod) while fusing.  Even the term 'fusion' made more sense as you were directly combining a set of mods with another to improve it.  Now you break down your duplicates into Endo and fuse the Endo into the mods.  It has made it a lot quicker to level mods when you want as you just click the arrow to bump it.  Then if you run low on Endo, or just feel like tidying your collection, you can 'Sort by: Duplicates' and melt down all the stacks of spares at once.

Thank you for your rich answer. They should remove the  "select mods from the collection to contribute towards ranking up x" then I suppose. Good to know that I'm not missing out on anything important.